Effects of Diazoxide-Mediated Insulin Suppression on Glucose and Lipid Metabolism in Nondiabetic Obese Men

Effects of Diazoxide-Mediated Insulin Suppression on Glucose and Lipid Metabolism in Nondiabetic... Abstract Context It has been suggested that stimulation of lipolysis by diazoxide (DZX)-mediated insulin suppression may be useful in treating obesity. However, the optimal dose to promote lipolysis without causing hyperglycemia is unknown. Objective To assess the effects of DZX in nondiabetic obese men on lipid and glucose metabolism. Design Double-blind, placebo (PL)-controlled, 6-month trial in men with a body mass index of 30 to 37.5 kg/m2 treated with a combination of caloric restriction, a standardized exercise program, and DZX or PL dose escalation. Results The mean maximal tolerated dose of DZX was 422 ± 44 mg/d (range, 200 to 700 mg/d). Dose-limiting events were edema (n = 11), hyperglycemia (n = 6), and nausea (n = 2). After dose reduction to a level free of clinical side effects, DZX treatment was associated with a markedly greater decrease in fasting insulin levels than PL (−72.3 ± 3.5% vs −23.0 ± 12.6%; P < 0.001) and a significant improvement of blood pressure and plasma lipid levels. The decline in insulin levels occurred at the cost of a small increase in plasma glucose (0.6 ± 0.2 mmol/L vs −0.1 ± 0.1 mmol/L; P = 0.04) and hemoglobin A1C (0.2 ± 0.1% vs 0.0 ± 0.1%; P = 0.17). Conclusion In nondiabetic obese men, insulin levels can be reduced up to 70% without major metabolic side effects. The marked intersubject variation in maximal tolerated dose indicates that DZX dose titration needs to be individualized. Hyperinsulinism is a major characteristic of obesity (1). It is generally regarded as the result of a compensatory β-cell response to overcome resistance to the glucose-lowering actions of insulin. Although this increased insulin secretion may help to maintain normoglycemia, it has adverse effects on body composition (2). Insulin not only promotes glucose uptake; it also increases intracellular fat storage by stimulating lipogenesis and inhibition of lipolysis (3–5). This may be life saving when energy availability is limited, but, in a setting of caloric abundance, these fat-storing actions of insulin can be detrimental. It has been shown that obese subjects remain relatively sensitive to the lipogenic and antilipolytic actions of insulin despite marked resistance to its glucose-lowering effects, and this may explain to some extent why it is difficult to lose excess fat (6). The potent obesogenic effects of excess insulin are well known in patients with type 2 diabetes mellitus starting insulin treatment, whereas the marked loss of fat that occurs in de novo type 1 diabetes mellitus illustrates the potential effects of insulin lowering on body fat mass (7). In view of these observations, it is not surprising that the concept of diazoxide (DZX)-mediated, controlled insulin suppression has emerged as an approach to support weight loss (8). Although DZX is a well-known inhibitor of glucose-stimulated insulin secretion, clinical data are limited, and the therapeutic window of DZX treatment is largely unknown. Alemzadeh et al. (8) demonstrated the effect of DZX-mediated insulin suppression in an 8-week, placebo (PL)-controlled study in obese adults (mainly women) with a mean body mass index (BMI) of 40 ± 2 kg/m2. DZX at 200 mg/d induced a 5-kg PL-subtracted weight loss without deleterious effects on glucose metabolism. Long-term studies have not been performed in women, probably because of the risk of hypertrichosis, a well-known side effect of DZX. A short-term, dose-response study in men revealed that the insulin-suppressive effects are dose dependent and that obese men require substantially higher doses to obtain the same degree of insulin suppression as achieved in nonobese men (9). The markedly lower efficacy in obese men was explained by lower plasma DZX levels as a result of weight-dependent differences in distribution volume. The efficacy of high-dose DZX–mediated insulin suppression in nondiabetic obese men has been explored in a 6-month, open, uncontrolled pilot study using DZX at a gradually increasing dose up to 900 mg/d in combination with moderate caloric restriction and increased physical activity (10). This regimen induced a 65% suppression of insulin levels and a mean decrease in fat mass of 23%. The degree of fat loss was inversely related to fasting insulin levels achieved at 6 months, and the data indicated that fat mass decreased by ≥10 kg if fasting insulin levels were reduced to ≤4.5 mU/L. This insulin level may be the target of treatment in future studies. However, further research is needed to define the therapeutic window of DZX-medicated insulin suppression to avoid the metabolic complications of excessive insulin suppression (11). The current study was designed to explore the efficacy and adverse effects of high-dose DZX–mediated insulin suppression in men in a PL-controlled setting. In this report we focus on the consequences of insulin suppression on glucose and lipid metabolism. The effects on body composition are discussed in a separate paper. In a subgroup of subjects, metformin (MTF) was added to assess its efficacy in preventing DZX-induced hyperglycemia. Subjects and Methods Subjects Obese but otherwise healthy men (age, 20 to 55 years; BMI, 30 to 37.5 kg/m2) were recruited by advertisement in local newspapers. All subjects received a general physical examination and a laboratory screening after an overnight fast. Men with a fasting serum glucose level ≤6 mmol/L, a hemoglobin A1C (HbA1c) level ≤6.0% (42 mmol/mol), a fasting C-peptide level ≥1.0 nmol/L, and a stable body weight for at least 3 months were eligible for inclusion. Women were excluded because of the risk of hypertrichosis. Exclusion criteria were any endocrine disease, serum creatinine >120 µmol/L, liver enzymes >2 times the upper limit of normal, continued use of medication affecting blood pressure or glucose and lipid metabolism, drug abuse, gout, use of alcohol >2 U/d, and cessation of smoking in the past 6 months. Antihypertensive or lipid-lowering drugs were discontinued 4 weeks prior to start of the study. The study was approved by the Institutional Review Board. All participating subjects gave written informed consent. Study design Patients were randomized in a double-blind manner to one of three treatment arms: DZX + PL (DZX+PL), DZX + MTF, and double PL (PL+PL). DZX was started at a dose of 100 mg twice daily with monthly increments of 100 mg/d until side effects or hyperglycemia occurred or until the maximum dose of 700 mg/d at 6 months was reached. The dose escalation schedule is summarized in Table 1. Tablets were taken at breakfast, at lunch, at dinner, and prior to bedtime. MTF was started in a dose of 850 mg once daily with weekly increments of 850 mg/d up to a maximum dose of 3 × 850 mg or until gastrointestinal side effects occurred. Prior to the study, caloric intake was assessed by a dietician. At the start of the study, diet and physical exercise were standardized. A mild hypocaloric diet was prescribed consisting of 75% of the calories required to maintain ideal body weight, as calculated by the Harris-Benedict equation (12). All subjects were instructed to eat only three meals a day with a carbohydrate-fat-protein content of 50%, 30%, and 20%, respectively. Subjects were instructed to walk for 30 minutes after lunch and dinner and to aim for 10,000 steps a day. In addition, they were instructed to visit the sports center (Physique, Arnhem, Netherlands) three times a week to receive standardized training by two physiotherapists. Attendance to the sport center was recorded. Table 1. DZX and PL Dose Escalation Schedule Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 View Large Table 1. DZX and PL Dose Escalation Schedule Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 View Large Measurements Baseline measurements included height, weight, blood pressure, home glucose measurements for 2 days, and the number of steps per week measured by pedometer (Omron Healthcare Europe, Hoofddorp, The Netherlands). A 24-hour urine sample was collected to measure total volume, creatinine, and glucose excretion. A fasting blood sample was obtained between 8:00 and 9:00 am to measure total blood count, plasma glucose, insulin, C-peptide, HbA1c, creatinine, sodium, potassium, uric acid, lactic acid, liver enzymes, lipid profile, β-hydroxybutyric acid, aceto-acetate, and free fatty acid (FFA) levels. In addition, a standardized 500 kcal meal test was performed to document the glucose and insulin level response as described previously (9). During this test, venous blood samples were taken at −30, 0, 30, 45, 60, 90, 120, 180, 240, and 300 minutes from a catheter inserted in a forearm vein. All baseline measurements were repeated at 6 months. The main outcome measurements were insulin, glucose, HbA1c, lipid levels, and reported side effects. A homeostatic model assessment of insulin resistance (HOMA-IR) was performed (13). Patients visited the outpatient clinic monthly for measurement of body weight, blood pressure, abdominal circumference, and blood glucose levels. Blood pressure was measured in the upright position with an automatic device (Omron M3) (Omron Healthcare Europe) after a 5-minute rest. Laboratory assays Commercially available methods were used to measure plasma glucose (enzymatic colorimetric assay, p800; Roche Diagnostics, Mannheim, Germany), plasma insulin (electrochemiluminescence immunoassay, Elecsys 2010; Roche Diagnostics), plasma C-peptide concentrations (competitive chemiluminescent enzyme immunoassay; DPC, Los Angeles, CA, manufacturer’s reference for fasting levels in nonobese subjects: 0.15 to 1.00 nmol/L), and HbA1c (reversed-phase cation exchange chromatography, ADAMS HA-8160; Menarini, Florence, Italy). Fasting FFA levels, fasting β-hydroxy butric acid, and aceto-acetate were measured enzymatically by spectrophotometric assays (ABX Pentra 400; Horiba ABX Diagnostics, Kyoto, Japan). Plasma DZX levels were analyzed by high-pressure liquid chromatography with ultraviolet detection as described previously (9). Lactic acid was measured potentiometrically (Cobas b 221; Roche Diagnostics). Safety monitoring All subjects were instructed to perform an eight-point home glucose measurement in the week preceding the monthly outpatient clinic visit (Accu-check; Roche Diagnostics), with blood samples taken in the fasting state, 2 hours after breakfast, just before lunch, 2 hours after lunch, before dinner, 2 hours after dinner, at bedtime, and at 3:00 am. Subjects were instructed to contact the trial investigators prior to the planned visits if side effects or hyperglycemia occurred. Hyperglycemia was defined as a fasting home glucose level >7 or >11 mmol/L 2 hours after a meal. Every 4 weeks, fasting glucose, insulin, and blood pressure were measured, and a 24-hour urine sample was collected to quantify glucosuria. In the case of DZX-related side effects (e.g., edema, hyperglycemia, glucosuria, systolic blood pressure <110 mm Hg, or diastolic blood pressure <70 mm Hg), the DZX dose was reduced 100 mg/d every 2 to 4 weeks until all side effects disappeared. In the case of persisting edema, an additional blood sample was taken to measure N-terminal prohormone of brain natriuretic peptide (NT-pro-BNP). Statistical analysis All data are shown as mean ± standard error of the mean. The results were analyzed as per protocol. Data from patients on active treatment were excluded if plasma DZX levels were undetectable because this suggested noncompliance. Differences between the three groups were analyzed by one-way analysis of variance with Bonferroni correction for post hoc multiple comparisons testing. Differences within groups were analyzed by paired t test. In the case of a non–Gaussian distribution, the Kruskal-Wallis and Wilcoxon matched pairs tests were used. To calculate correlations, Pearson’s correlation test was used. A P value <0.05 was considered statistically significant. Results Forty-four men were included in this study (Fig. 1). Nine men dropped out during the initial 4 weeks of the study: three for personal reasons unrelated to the trial, two because of side effects (MTF-related gastrointestinal symptoms and MTF-induced rash), and four because of early-onset motivational problems and/or inability to adhere to the physical exercise protocol. Thirty-five men completed the 6-month study according to protocol: 12 in the PL+PL arm, 10 in the DZX+PL arm, and 13 in the DZX+MTF arm. Figure 1. View largeDownload slide Randomization and study completion. Figure 1. View largeDownload slide Randomization and study completion. Baseline results Mean age at baseline was 44.7 ± 1.2 years (range, 22.9 to 54.3 years), and mean BMI was 35.1 ± 0.4 kg/m2. Fasting C-peptide and insulin levels ranged from 1.0 to 1.9 nmol/L and from 8.5 to 34.5 mU/L, respectively. Two men had obstructive sleep apnea syndrome requiring continuous positive airway pressure (DZX+MTF arm), three men used antihypertensive medication (low-dose β-blocker, diuretic, and angiotensin-converting enzyme inhibitor, respectively; one patient in each arm), and three men used a statin (one patient in each arm). Antihypertensives and statins had been discontinued 4 weeks prior to start of the study, according to protocol. At baseline, the three groups were well matched for all parameters except for a slightly higher low-density lipoprotein cholesterol (LDL-C) level in the DZX+PL group (Table 1). The reported caloric intake prior to the study was 2428 ± 102 kcal/d. The recommended intake during the study was 1627 ± 37 kcal/d, which represents a reduction of 30.9% ± 2.8% compared with the prestudy intake (P < 0.001). DZX dose and side effects The most frequently reported side effects during dose escalation were transient nausea (n = 11 in the DZX+MTF arm, n = 1 in the DZX+PL and PL+PL arms), loose stools (n = 2 in the DZX+MTF arm and n = 1 in the DZX+PL and PL+PL arms), edema (n = 8 in the DZX+MTF arm, n = 3 in the DZX+PL arm, and n = 1 in the PL+PL arm), hypertrichosis (n = 2 in both DZX arms and n = 1 in the PL+PL arm), and palpitations (n = 3 in the DZX+PL arm). The dose-limiting events were hyperglycemia (n = 3 in both DZX arms), edema (n = 8 in the DZX+MTF arm, n = 3 in the DZX+PL arm, and n = 1 in the PL+PL arm), and nausea (n = 1 in both DZX arms). Transient glucosuria was detected in three men at 2, 3, and 5 months, respectively (one in the DZX+PL arm and two in the DZX+MTF arm). All side effects disappeared after dose reduction, and none of the patients had side effects or glucosuria at 6 months. The achieved mean daily DZX dose was 422 ± 62 mg in the DZX+PL arm and 442 ± 34 mg in the DZX+MTF arm (Fig. 2). Only two men reached the maximum dose of 700 mg/d. The plasma DZX levels at 6 months were 37.9 ± 8.8 mg/L and 38.8 ± 5.1 mg/L (P = 0.85), respectively. DZX was not detectable in the PL+PL group. All but one subject tolerated MTF at a dose of 2250 mg/d. Figure 2. View largeDownload slide Mean diazoxide dose (left) and plasma levels (right) during the study in the DZX-MTF arm (black bars and filled circle), DZX-PL arm (open bars and open circle), and PL+PL arm (hexagon). Figure 2. View largeDownload slide Mean diazoxide dose (left) and plasma levels (right) during the study in the DZX-MTF arm (black bars and filled circle), DZX-PL arm (open bars and open circle), and PL+PL arm (hexagon). Effects on serum insulin and glucose levels After 6 months, PL+PL treatment was associated with a 23% reduction in fasting insulin, without a change in glucose levels. DZX treatment reduced fasting insulin levels by >70% (P < 0.001), from 15.5 ± 2.6 to 5.6 ± 1.7 mU/L (P < 0.01) and from 14.6 ± 1.9 to 4.1 ± 09 mU/L (P < 0.001) in the DZX+PL and DZX+MTF groups, respectively. Postmeal peak insulin and area under the curve insulin (AUC)Ins decreased by 67% (Fig. 3). This reduction in insulin levels was associated with a small but significant increase in fasting glucose levels in both DZX groups: 0.7 ± 0.2 mmol/L [95% confidence interval (CI), 0.1 to 1.2] in the DZX+PL arm and 0.6 ± 0.3 mmol/L (95% CI, 0.0 to 1.1) in the DZX+MTF arm (Table 1). Postmeal peak glucose levels increased by 1.5 ± 0.4 and 1.1 ± 0.6 mmol/L, and AUCGluc increased by 16% in both groups. HbA1c increased by 0.3 ± 0.1% (95% CI, 0.0 to 0.7) and 0.2 ± 0.1% (95% CI, 0.0 to 0.4), respectively. Effects on lipids In the PL+PL arm, high-density lipoprotein cholesterol (HDL-C) and LDL-C did not change significantly, whereas triglycerides (TGs) decreased by 14% (P < 0.05). Both DZX groups had significant improvements in TG, HDL-C, and LDL-C levels as compared with PL (P < 0.001). DZX treatment increased HDL-C by 36% and 25%, and plasma (TG) decreased by 58% and 43% in the DZX+PL and DZX+MTF arms, respectively (Fig. 4). LDL-C decreased by 20% in both DZX groups. HDL-C levels were inversely related to fasting insulin levels, AUCins, and HOMA-IR (r = −0.46, r = −0.44, and r = −0.40, respectively; P < 0.001 for all). TG levels were positively correlated with fasting insulin levels (r = 0.23; P = 0.02). Levels of FFA, β-hydroxybutyric acid, and aceto-acetate showed no significant change within or between the three treatment arms (data not shown). Figure 3. View largeDownload slide Serum insulin and glucose responses to a standardized test meal before (open symbols) and after (filled symbols) 6 months of treatment. Figure 3. View largeDownload slide Serum insulin and glucose responses to a standardized test meal before (open symbols) and after (filled symbols) 6 months of treatment. Figure 4. View largeDownload slide Change in plasma TGs, HDL-C, and LDL-C after 6 months in the PL+PL (open bar), DZX+PL (dashed bar), and DZX+MTF (filled bar) arm. *P < 0.05 compared with PL+PL. Figure 4. View largeDownload slide Change in plasma TGs, HDL-C, and LDL-C after 6 months in the PL+PL (open bar), DZX+PL (dashed bar), and DZX+MTF (filled bar) arm. *P < 0.05 compared with PL+PL. Effects on other parameters A PL-subtracted decline in systolic blood pressure of 10.4 mm Hg (P = 0.09) and a PL-subtracted decline in diastolic blood pressure of 6.3 mm Hg (P = 0.19) were observed in the DZX arms. When both DZX arms were combined, the PL-subtracted declines in systolic and diastolic blood pressure reached statistical significance (P = 0.02 and P = 0.05, respectively). No significant changes were observed between the three arms regarding hemoglobin, leukocyte and thrombocyte count, plasma creatinine or electrolyte levels, uric acid, or thyroid and gonadal hormones. In the case of persistent edema (n = 10), NT-pro-BNP levels were measured. Levels ranged from 1 to 18 pmol/L and did not exceed the upper limit of normal (<21 pmol/L). DZX with or without MTF The results of DZX treatment with or without MTF are shown in Table 2. The declines in body weight, blood pressure, and insulin levels and the changes in glucose and lipid levels were of similar magnitude in both groups. MTF use was associated with a slightly lower postmeal peak glucose but had no significant effect on other parameters of glucose control. Gastrointestinal side effects were much more common in patients using DZX+MTF. Table 2. Baseline Characteristics and Changes After 6 Months PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f Abbreviations: BP, blood pressure; ND, not detectable. a Significance of changes within groups: P < 0.001. b P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and DZX+PL vs PL+PL. c Significance of changes within groups: P < 0.01. d Significance of changes within groups: P < 0.05. e P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and PL+PL vs DZX+PL. f P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+PL and PL+PL. View Large Table 2. Baseline Characteristics and Changes After 6 Months PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f Abbreviations: BP, blood pressure; ND, not detectable. a Significance of changes within groups: P < 0.001. b P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and DZX+PL vs PL+PL. c Significance of changes within groups: P < 0.01. d Significance of changes within groups: P < 0.05. e P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and PL+PL vs DZX+PL. f P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+PL and PL+PL. View Large Discussion The present study focused on the safety aspects of DZX as monotherapy or in combination with MTF as a treatment of obesity in nondiabetic men and describes the effects of DZX on glucose and lipid metabolism. DZX treatment for 6 months lowered insulin levels by >70%, compared with a 24% reduction in the PL+PL arm. This decrease in insulin levels was associated with a large improvement in plasma lipid levels at the cost of a small rise in glucose levels. Insulin resistance evaluated by HOMA-IR showed a 70% improvement in insulin sensitivity. Obesity-related hyperinsulinemia is generally viewed as a compensatory β-cell response to overcome the resistance to the glucose-lowering actions of insulin. However, sustained hyperinsulinism can also cause insulin resistance by a decline in insulin receptors and/or postreceptor defects (14–17). In contrast, forced DZX-mediated insulin suppression has been shown to increase insulin sensitivity in animals and in humans (8, 18). The marked improvement in insulin sensitivity explains why a 70% decrease in insulin levels did not lead to overt diabetes mellitus but only caused mild glucose intolerance. It is conceivable that glucose intolerance as a result of forced insulin lowering can be avoided by individualized DZX dose adjustment. The main aim of the current study was to find the optimal DZX dose to achieve maximal insulin suppression without causing metabolic harm that would outweigh the beneficial effects of weight loss. At 6 months, fasting glucose levels had increased slightly in the DZX+PL group as compared with the PL+PL arm. Fasting glucose levels >5.0 mmol/L are associated with a higher risk for cardiovascular disease. The hazard ratio adjusted for age, smoking status, alcohol, exercise, BMI, and systolic blood pressure in men with a fasting glucose level between 6.1 and 6.4 mmol/L is 5% to 12% higher when compared with a fasting glucose of 5 mmol/L (19, 20). To determine the total cost/benefit ratio, the adverse effects on glucose metabolism should be weighed against the beneficial effects on lipid levels and blood pressure. Compared with the PL+PL group, DZX caused a fourfold increase in HDL-C and a fourfold higher decline in LDL-C and TG levels, which has been shown to substantially reduce the risk of cardiovascular disease (21, 22). In addition, the PL-subtracted 10 mm Hg decline in systolic blood pressure may have a positive effect on cardiovascular risk (23). The improvements in blood pressure and lipid levels are likely to outweigh the risks associated with a modest deterioration in glucose metabolism. These expectations are supported by findings in recent rodent studies demonstrating that insulin lowering had no prolonged adverse effects on glucose homeostasis but was associated with reduced adiposity and substantial lifespan extension (24). The design of the current study included a treatment arm with the combination of DZX and MTF. MTF was added to reduce the risk of hyperglycemia and because of its potential effects on weight loss (25–28). PL-controlled trials in obese hyperinsulinemic adolescents or adults without diabetes have shown that MTF at 1000 to 1700 mg/d for 2 to 6 months induces a 3-kg PL-subtracted weight loss and an increase in insulin sensitivity (26–28). In our study, adding MTF to DZX did not increase weight loss, had no protective effect on fasting and peak glucose levels, and had no additional beneficial effects on lipid levels. The beneficial effects of DZX on lipid levels were in line with expectations based on previous observations documenting the central role of insulin in the control of lipid metabolism and body fat mass (16, 29–31). Insulin suppresses intracellular lipolysis by inhibition of the adipocyte’s hormone-sensitive lipase, promotes hepatic and adipocyte lipogenesis by increasing FFA uptake by stimulation of lipoprotein lipase–mediated release of FFA from lipoprotein TGs, and increases glycerol-3 phosphate availability by stimulation of glucose uptake (16, 30–32). The reverse occurs with DZX-mediated insulin suppression. The decline in plasma TGs and LDL-C is due to decreased production and increased catabolism of TG-rich lipoproteins, and the rise in HDL-C can be attributed to a decrease in HDL-C catabolism (31, 32). Hyperglycemia and edema were the main dose-limiting effects of DZX treatment. Both effects disappeared after dose reduction. Edema was not related to changes in plasma albumin. The minor decrease in albumin levels during DZX treatment (–1.2 ± 0.7 g/L for both DZX arms; P = 0.43) was too small to explain the onset of edema. DZX is known to produce vasodilation and causes sodium and water retention that is probably secondary to the decrease in intravascular pressure (33, 34). Increased capillary permeability might be an additional explanation. We found no evidence of congestive heart failure. NT-pro-BNP levels were well within the normal range. Our study has limitations. Because of its small numbers, it should be regarded as an explorative study that requires confirmation by larger studies. Furthermore, the present data cannot be extrapolated to women. It appears that women are more sensitive to the insulin-suppressive effects of DZX than men (9). In summary, DZX treatment, combined with increased physical exercise and moderate caloric restriction, reduces insulin levels by 70% without causing major increases in glucose levels and has beneficial effects on lipid levels and blood pressure. The large interindividual variation in maximal tolerated dose of DZX underscores the need for individualized dose titration. The main dose-limiting effects were hyperglycemia and edema; both were reversible after dose reduction. Abbreviations: Abbreviations: AUC area under the curve BMI body mass index CI confidence interval DZX diazoxide FFA free fatty acid HbA1c hemoglobin A1C HDL-C high-density lipoprotein cholesterol HOMA-IR homeostatic model assessment of insulin resistance LDL-C low-density lipoprotein cholesterol MTF metformin NT-pro-BNP N-terminal prohormone of brain natriuretic peptide PL placebo TG triglyceride Acknowledgments Clinical Trial Information: ClinicalTrials.gov no. NCT00631033 (registered November 2004). Current Affiliation: S. Loves’ current affiliation is Treant Health Care Group, 7824 AA Emmen, Boermarkeweg 60, The Netherlands. Disclosure Summary: The authors have nothing to disclose. References 1. Polonsky KS , Given BD , Van Cauter E . Twenty-four-hour profiles and pulsatile patterns of insulin secretion in normal and obese subjects . J Clin Invest . 1988 ; 81 ( 2 ): 442 – 448 . Google Scholar CrossRef Search ADS PubMed 2. Le Stunff C , Bougnères P . Early changes in postprandial insulin secretion, not in insulin sensitivity, characterize juvenile obesity . Diabetes . 1994 ; 43 ( 5 ): 696 – 702 . Google Scholar CrossRef Search ADS PubMed 3. Cusin I , Terrettaz J , Rohner-Jeanrenaud F , Jeanrenaud B . Metabolic consequences of hyperinsulinaemia imposed on normal rats on glucose handling by white adipose tissue, muscles and liver . Biochem J . 1990 ; 267 ( 1 ): 99 – 103 . Google Scholar CrossRef Search ADS PubMed 4. Rizza RA , Mandarino LJ , Genest J , Baker BA , Gerich JE . Production of insulin resistance by hyperinsulinaemia in man . Diabetologia . 1985 ; 28 ( 2 ): 70 – 75 . Google Scholar PubMed 5. Arner P , Bolinder J , Engfeldt P , Hellmér J , Ostman J . Influence of obesity on the antilipolytic effect of insulin in isolated human fat cells obtained before and after glucose ingestion . J Clin Invest . 1984 ; 73 ( 3 ): 673 – 680 . Google Scholar CrossRef Search ADS PubMed 6. Howard BV , Klimes I , Vasquez B , Brady D , Nagulesparan M , Unger RH . The antilipolytic action of insulin in obese subjects with resistance to its glucoregulatory action . J Clin Endocrinol Metab . 1984 ; 58 ( 3 ): 544 – 548 . Google Scholar CrossRef Search ADS PubMed 7. Templeman NM , Skovsø S , Page MM , Lim GE , Johnson JD . A causal role for hyperinsulinemia in obesity . J Endocrinol . 2017 ; 232 ( 3 ): R173 – R183 . Google Scholar CrossRef Search ADS PubMed 8. Alemzadeh R , Langley G , Upchurch L , Smith P , Slonim AE . Beneficial effect of diazoxide in obese hyperinsulinemic adults . J Clin Endocrinol Metab . 1998 ; 83 ( 6 ): 1911 – 1915 . Google Scholar PubMed 9. Schreuder T , Karreman M , Rennings A , Ruinemans-Koerts J , Jansen M , de Boer H . Diazoxide-mediated insulin suppression in obese men: a dose-response study . Diabetes Obes Metab . 2005 ; 7 ( 3 ): 239 – 245 . Google Scholar CrossRef Search ADS PubMed 10. van Boekel G , Loves S , van Sorge A , Ruinemans-Koerts J , Rijnders T , de Boer H . Weight loss in obese men by caloric restriction and high-dose diazoxide-mediated insulin suppression . Diabetes Obes Metab . 2008 ; 10 ( 12 ): 1195 – 1203 . Google Scholar PubMed 11. Lewis GF , Carpentier A , Adeli K , Giacca A . Disordered fat storage and mobilization in the pathogenesis of insulin resistance and type 2 diabetes . Endocr Rev . 2002 ; 23 ( 2 ): 201 – 229 . Google Scholar CrossRef Search ADS PubMed 12. Harris JA , Benedict FG . A biometric study of human basal metabolism on men . Proc Natl Acad Sci USA . 1918 ; 4 ( 12 ): 370 – 373 . Google Scholar CrossRef Search ADS PubMed 13. Matthews DR , Hosker JP , Rudenski AS , Naylor BA , Treacher DF , Turner RC . Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man . Diabetologia . 1985 ; 28 ( 7 ): 412 – 419 . Google Scholar CrossRef Search ADS PubMed 14. Shanik MH , Xu Y , Skrha J , Dankner R , Zick Y , Roth J . Insulin resistance and hyperinsulinemia: is hyperinsulinemia the cart or the horse ? Diabetes Care . 2008 ; 31 ( Suppl 2 ): S262 – S268 . Google Scholar CrossRef Search ADS PubMed 15. Koopmans SJ , Ohman L , Haywood JR , Mandarino LJ , DeFronzo RA . Seven days of euglycemic hyperinsulinemia induces insulin resistance for glucose metabolism but not hypertension, elevated catecholamine levels, or increased sodium retention in conscious normal rats . Diabetes . 1997 ; 46 ( 10 ): 1572 – 1578 . Google Scholar CrossRef Search ADS PubMed 16. Samuel VT , Shulman GI . The pathogenesis of insulin resistance: integrating signaling pathways and substrate flux . J Clin Invest . 2016 ; 126 ( 1 ): 12 – 22 . Google Scholar CrossRef Search ADS PubMed 17. Wigand JP , Blackard WG . Downregulation of insulin receptors in obese man . Diabetes . 1979 ; 28 ( 4 ): 287 – 291 . Google Scholar CrossRef Search ADS PubMed 18. Alemzadeh R , Jacobs W , Pitukcheewanont P . Antiobesity effect of diazoxide in obese Zucker rats . Metabolism . 1996 ; 45 ( 3 ): 334 – 341 . Google Scholar CrossRef Search ADS PubMed 19. Park C , Guallar E , Linton JA , Lee DC , Jang Y , Son DK , Han EJ , Baek SJ , Yun YD , Jee SH , Samet JM . Fasting glucose level and the risk of incident atherosclerotic cardiovascular diseases . Diabetes Care . 2013 ; 36 ( 7 ): 1988 – 1993 . Google Scholar CrossRef Search ADS PubMed 20. Sung J , Song YM , Ebrahim S , Lawlor DA . Fasting blood glucose and the risk of stroke and myocardial infarction . Circulation . 2009 ; 119 ( 6 ): 812 – 819 . Google Scholar CrossRef Search ADS PubMed 21. Gordon DJ , Probstfield JL , Garrison RJ , Neaton JD , Castelli WP , Knoke JD , Jacobs DR Jr , Bangdiwala S , Tyroler HA . High-density lipoprotein cholesterol and cardiovascular disease. Four prospective American studies . Circulation . 1989 ; 79 ( 1 ): 8 – 15 . Google Scholar CrossRef Search ADS PubMed 22. Baigent C , Keech A , Kearney PM , Blackwell L , Buck G , Pollicino C , Kirby A , Sourjina T , Peto R , Collins R , Simes R ; Cholesterol Treatment Trialists’ (CTT) Collaborators . Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90,056 participants in 14 randomised trials of statins . Lancet . 2005 ; 366 ( 9493 ): 1267 – 1278 . Google Scholar CrossRef Search ADS PubMed 23. Borghi C , Dormi A , L’Italien G , Lapuerta P , Franklin SS , Collatina S , Gaddi A . The relationship between systolic blood pressure and cardiovascular risk: results of the Brisighella Heart Study . J Clin Hypertens (Greenwich) . 2003 ; 5 ( 1 ): 47 – 52 . Google Scholar CrossRef Search ADS PubMed 24. Templeman NM , Flibotte S , Chik JHL , Sinha S , Lim GE , Foster LJ , Nislow C , Johnson JD . Reduced circulating insulin enhances insulin sensitivity in old mice and extends lifespan . Cell Reports . 2017 ; 20 ( 2 ): 451 – 463 . Google Scholar CrossRef Search ADS PubMed 25. Aroda VR , Knowler WC , Crandall JP , Perreault L , Edelstein SL , Jeffries SL , Molitch ME , Pi-Sunyer X , Darwin C , Heckman-Stoddard BM , Temprosa M , Kahn SE , Nathan DM ; Diabetes Prevention Program Research Group . Metformin for diabetes prevention: insights gained from the Diabetes Prevention Program/Diabetes Prevention Program Outcomes Study . Diabetologia . 2017 ; 60 ( 9 ): 1601 – 1611 . Google Scholar CrossRef Search ADS PubMed 26. Kay JP , Alemzadeh R , Langley G , D’Angelo L , Smith P , Holshouser S . Beneficial effects of metformin in normoglycemic morbidly obese adolescents . Metabolism . 2001 ; 50 ( 12 ): 1457 – 1461 . Google Scholar CrossRef Search ADS PubMed 27. Atabek ME , Pirgon O . Use of metformin in obese adolescents with hyperinsulinemia: a 6-month, randomized, double-blind, placebo-controlled clinical trial . J Pediatr Endocrinol Metab . 2008 ; 21 ( 4 ): 339 – 348 . Google Scholar CrossRef Search ADS PubMed 28. Stumvoll M , Nurjhan N , Perriello G , Dailey G , Gerich JE . Metabolic effects of metformin in non-insulin-dependent diabetes mellitus . N Engl J Med . 1995 ; 333 ( 9 ): 550 – 554 . Google Scholar CrossRef Search ADS PubMed 29. Olefsky JM , Farquhar JW , Reaven GM . Reappraisal of the role of insulin in hypertriglyceridemia . Am J Med . 1974 ; 57 ( 4 ): 551 – 560 . Google Scholar CrossRef Search ADS PubMed 30. Farese RV Jr , Yost TJ , Eckel RH . Tissue-specific regulation of lipoprotein lipase activity by insulin/glucose in normal-weight humans . Metabolism . 1991 ; 40 ( 2 ): 214 – 216 . Google Scholar CrossRef Search ADS PubMed 31. Vergès B . Pathophysiology of diabetic dyslipidaemia: where are we ? Diabetologia . 2015 ; 58 ( 5 ): 886 – 899 . Google Scholar CrossRef Search ADS PubMed 32. Czech MP , Tencerova M , Pedersen DJ , Aouadi M . Insulin signalling mechanisms for triacylglycerol storage . Diabetologia . 2013 ; 56 ( 5 ): 949 – 964 . Google Scholar CrossRef Search ADS PubMed 33. van Hamersvelt HW , Kloke HJ , de Jong DJ , Koene RA , Huysmans FT . Oedema formation with the vasodilators nifedipine and diazoxide: direct local effect or sodium retention ? J Hypertens . 1996 ; 14 ( 8 ): 1041 – 1045 . Google Scholar CrossRef Search ADS PubMed 34. Koch-Weser J . Diazoxide . N Engl J Med . 1976 ; 294 ( 23 ): 1271 – 1273 . Copyright © 2018 Endocrine Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Clinical Endocrinology and Metabolism Oxford University Press

Effects of Diazoxide-Mediated Insulin Suppression on Glucose and Lipid Metabolism in Nondiabetic Obese Men

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Endocrine Society
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Copyright © 2018 Endocrine Society
ISSN
0021-972X
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1945-7197
D.O.I.
10.1210/jc.2018-00161
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Abstract

Abstract Context It has been suggested that stimulation of lipolysis by diazoxide (DZX)-mediated insulin suppression may be useful in treating obesity. However, the optimal dose to promote lipolysis without causing hyperglycemia is unknown. Objective To assess the effects of DZX in nondiabetic obese men on lipid and glucose metabolism. Design Double-blind, placebo (PL)-controlled, 6-month trial in men with a body mass index of 30 to 37.5 kg/m2 treated with a combination of caloric restriction, a standardized exercise program, and DZX or PL dose escalation. Results The mean maximal tolerated dose of DZX was 422 ± 44 mg/d (range, 200 to 700 mg/d). Dose-limiting events were edema (n = 11), hyperglycemia (n = 6), and nausea (n = 2). After dose reduction to a level free of clinical side effects, DZX treatment was associated with a markedly greater decrease in fasting insulin levels than PL (−72.3 ± 3.5% vs −23.0 ± 12.6%; P < 0.001) and a significant improvement of blood pressure and plasma lipid levels. The decline in insulin levels occurred at the cost of a small increase in plasma glucose (0.6 ± 0.2 mmol/L vs −0.1 ± 0.1 mmol/L; P = 0.04) and hemoglobin A1C (0.2 ± 0.1% vs 0.0 ± 0.1%; P = 0.17). Conclusion In nondiabetic obese men, insulin levels can be reduced up to 70% without major metabolic side effects. The marked intersubject variation in maximal tolerated dose indicates that DZX dose titration needs to be individualized. Hyperinsulinism is a major characteristic of obesity (1). It is generally regarded as the result of a compensatory β-cell response to overcome resistance to the glucose-lowering actions of insulin. Although this increased insulin secretion may help to maintain normoglycemia, it has adverse effects on body composition (2). Insulin not only promotes glucose uptake; it also increases intracellular fat storage by stimulating lipogenesis and inhibition of lipolysis (3–5). This may be life saving when energy availability is limited, but, in a setting of caloric abundance, these fat-storing actions of insulin can be detrimental. It has been shown that obese subjects remain relatively sensitive to the lipogenic and antilipolytic actions of insulin despite marked resistance to its glucose-lowering effects, and this may explain to some extent why it is difficult to lose excess fat (6). The potent obesogenic effects of excess insulin are well known in patients with type 2 diabetes mellitus starting insulin treatment, whereas the marked loss of fat that occurs in de novo type 1 diabetes mellitus illustrates the potential effects of insulin lowering on body fat mass (7). In view of these observations, it is not surprising that the concept of diazoxide (DZX)-mediated, controlled insulin suppression has emerged as an approach to support weight loss (8). Although DZX is a well-known inhibitor of glucose-stimulated insulin secretion, clinical data are limited, and the therapeutic window of DZX treatment is largely unknown. Alemzadeh et al. (8) demonstrated the effect of DZX-mediated insulin suppression in an 8-week, placebo (PL)-controlled study in obese adults (mainly women) with a mean body mass index (BMI) of 40 ± 2 kg/m2. DZX at 200 mg/d induced a 5-kg PL-subtracted weight loss without deleterious effects on glucose metabolism. Long-term studies have not been performed in women, probably because of the risk of hypertrichosis, a well-known side effect of DZX. A short-term, dose-response study in men revealed that the insulin-suppressive effects are dose dependent and that obese men require substantially higher doses to obtain the same degree of insulin suppression as achieved in nonobese men (9). The markedly lower efficacy in obese men was explained by lower plasma DZX levels as a result of weight-dependent differences in distribution volume. The efficacy of high-dose DZX–mediated insulin suppression in nondiabetic obese men has been explored in a 6-month, open, uncontrolled pilot study using DZX at a gradually increasing dose up to 900 mg/d in combination with moderate caloric restriction and increased physical activity (10). This regimen induced a 65% suppression of insulin levels and a mean decrease in fat mass of 23%. The degree of fat loss was inversely related to fasting insulin levels achieved at 6 months, and the data indicated that fat mass decreased by ≥10 kg if fasting insulin levels were reduced to ≤4.5 mU/L. This insulin level may be the target of treatment in future studies. However, further research is needed to define the therapeutic window of DZX-medicated insulin suppression to avoid the metabolic complications of excessive insulin suppression (11). The current study was designed to explore the efficacy and adverse effects of high-dose DZX–mediated insulin suppression in men in a PL-controlled setting. In this report we focus on the consequences of insulin suppression on glucose and lipid metabolism. The effects on body composition are discussed in a separate paper. In a subgroup of subjects, metformin (MTF) was added to assess its efficacy in preventing DZX-induced hyperglycemia. Subjects and Methods Subjects Obese but otherwise healthy men (age, 20 to 55 years; BMI, 30 to 37.5 kg/m2) were recruited by advertisement in local newspapers. All subjects received a general physical examination and a laboratory screening after an overnight fast. Men with a fasting serum glucose level ≤6 mmol/L, a hemoglobin A1C (HbA1c) level ≤6.0% (42 mmol/mol), a fasting C-peptide level ≥1.0 nmol/L, and a stable body weight for at least 3 months were eligible for inclusion. Women were excluded because of the risk of hypertrichosis. Exclusion criteria were any endocrine disease, serum creatinine >120 µmol/L, liver enzymes >2 times the upper limit of normal, continued use of medication affecting blood pressure or glucose and lipid metabolism, drug abuse, gout, use of alcohol >2 U/d, and cessation of smoking in the past 6 months. Antihypertensive or lipid-lowering drugs were discontinued 4 weeks prior to start of the study. The study was approved by the Institutional Review Board. All participating subjects gave written informed consent. Study design Patients were randomized in a double-blind manner to one of three treatment arms: DZX + PL (DZX+PL), DZX + MTF, and double PL (PL+PL). DZX was started at a dose of 100 mg twice daily with monthly increments of 100 mg/d until side effects or hyperglycemia occurred or until the maximum dose of 700 mg/d at 6 months was reached. The dose escalation schedule is summarized in Table 1. Tablets were taken at breakfast, at lunch, at dinner, and prior to bedtime. MTF was started in a dose of 850 mg once daily with weekly increments of 850 mg/d up to a maximum dose of 3 × 850 mg or until gastrointestinal side effects occurred. Prior to the study, caloric intake was assessed by a dietician. At the start of the study, diet and physical exercise were standardized. A mild hypocaloric diet was prescribed consisting of 75% of the calories required to maintain ideal body weight, as calculated by the Harris-Benedict equation (12). All subjects were instructed to eat only three meals a day with a carbohydrate-fat-protein content of 50%, 30%, and 20%, respectively. Subjects were instructed to walk for 30 minutes after lunch and dinner and to aim for 10,000 steps a day. In addition, they were instructed to visit the sports center (Physique, Arnhem, Netherlands) three times a week to receive standardized training by two physiotherapists. Attendance to the sport center was recorded. Table 1. DZX and PL Dose Escalation Schedule Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 View Large Table 1. DZX and PL Dose Escalation Schedule Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 Study Duration (wk) No. of Tablets (100 mg) Breakfast Lunch Dinner Bedtime 0–4 1 0 1 0 4–8 1 1 1 0 8–12 1 1 1 1 12–16 2 1 1 1 16–20 2 1 2 1 20–24 2 2 2 1 View Large Measurements Baseline measurements included height, weight, blood pressure, home glucose measurements for 2 days, and the number of steps per week measured by pedometer (Omron Healthcare Europe, Hoofddorp, The Netherlands). A 24-hour urine sample was collected to measure total volume, creatinine, and glucose excretion. A fasting blood sample was obtained between 8:00 and 9:00 am to measure total blood count, plasma glucose, insulin, C-peptide, HbA1c, creatinine, sodium, potassium, uric acid, lactic acid, liver enzymes, lipid profile, β-hydroxybutyric acid, aceto-acetate, and free fatty acid (FFA) levels. In addition, a standardized 500 kcal meal test was performed to document the glucose and insulin level response as described previously (9). During this test, venous blood samples were taken at −30, 0, 30, 45, 60, 90, 120, 180, 240, and 300 minutes from a catheter inserted in a forearm vein. All baseline measurements were repeated at 6 months. The main outcome measurements were insulin, glucose, HbA1c, lipid levels, and reported side effects. A homeostatic model assessment of insulin resistance (HOMA-IR) was performed (13). Patients visited the outpatient clinic monthly for measurement of body weight, blood pressure, abdominal circumference, and blood glucose levels. Blood pressure was measured in the upright position with an automatic device (Omron M3) (Omron Healthcare Europe) after a 5-minute rest. Laboratory assays Commercially available methods were used to measure plasma glucose (enzymatic colorimetric assay, p800; Roche Diagnostics, Mannheim, Germany), plasma insulin (electrochemiluminescence immunoassay, Elecsys 2010; Roche Diagnostics), plasma C-peptide concentrations (competitive chemiluminescent enzyme immunoassay; DPC, Los Angeles, CA, manufacturer’s reference for fasting levels in nonobese subjects: 0.15 to 1.00 nmol/L), and HbA1c (reversed-phase cation exchange chromatography, ADAMS HA-8160; Menarini, Florence, Italy). Fasting FFA levels, fasting β-hydroxy butric acid, and aceto-acetate were measured enzymatically by spectrophotometric assays (ABX Pentra 400; Horiba ABX Diagnostics, Kyoto, Japan). Plasma DZX levels were analyzed by high-pressure liquid chromatography with ultraviolet detection as described previously (9). Lactic acid was measured potentiometrically (Cobas b 221; Roche Diagnostics). Safety monitoring All subjects were instructed to perform an eight-point home glucose measurement in the week preceding the monthly outpatient clinic visit (Accu-check; Roche Diagnostics), with blood samples taken in the fasting state, 2 hours after breakfast, just before lunch, 2 hours after lunch, before dinner, 2 hours after dinner, at bedtime, and at 3:00 am. Subjects were instructed to contact the trial investigators prior to the planned visits if side effects or hyperglycemia occurred. Hyperglycemia was defined as a fasting home glucose level >7 or >11 mmol/L 2 hours after a meal. Every 4 weeks, fasting glucose, insulin, and blood pressure were measured, and a 24-hour urine sample was collected to quantify glucosuria. In the case of DZX-related side effects (e.g., edema, hyperglycemia, glucosuria, systolic blood pressure <110 mm Hg, or diastolic blood pressure <70 mm Hg), the DZX dose was reduced 100 mg/d every 2 to 4 weeks until all side effects disappeared. In the case of persisting edema, an additional blood sample was taken to measure N-terminal prohormone of brain natriuretic peptide (NT-pro-BNP). Statistical analysis All data are shown as mean ± standard error of the mean. The results were analyzed as per protocol. Data from patients on active treatment were excluded if plasma DZX levels were undetectable because this suggested noncompliance. Differences between the three groups were analyzed by one-way analysis of variance with Bonferroni correction for post hoc multiple comparisons testing. Differences within groups were analyzed by paired t test. In the case of a non–Gaussian distribution, the Kruskal-Wallis and Wilcoxon matched pairs tests were used. To calculate correlations, Pearson’s correlation test was used. A P value <0.05 was considered statistically significant. Results Forty-four men were included in this study (Fig. 1). Nine men dropped out during the initial 4 weeks of the study: three for personal reasons unrelated to the trial, two because of side effects (MTF-related gastrointestinal symptoms and MTF-induced rash), and four because of early-onset motivational problems and/or inability to adhere to the physical exercise protocol. Thirty-five men completed the 6-month study according to protocol: 12 in the PL+PL arm, 10 in the DZX+PL arm, and 13 in the DZX+MTF arm. Figure 1. View largeDownload slide Randomization and study completion. Figure 1. View largeDownload slide Randomization and study completion. Baseline results Mean age at baseline was 44.7 ± 1.2 years (range, 22.9 to 54.3 years), and mean BMI was 35.1 ± 0.4 kg/m2. Fasting C-peptide and insulin levels ranged from 1.0 to 1.9 nmol/L and from 8.5 to 34.5 mU/L, respectively. Two men had obstructive sleep apnea syndrome requiring continuous positive airway pressure (DZX+MTF arm), three men used antihypertensive medication (low-dose β-blocker, diuretic, and angiotensin-converting enzyme inhibitor, respectively; one patient in each arm), and three men used a statin (one patient in each arm). Antihypertensives and statins had been discontinued 4 weeks prior to start of the study, according to protocol. At baseline, the three groups were well matched for all parameters except for a slightly higher low-density lipoprotein cholesterol (LDL-C) level in the DZX+PL group (Table 1). The reported caloric intake prior to the study was 2428 ± 102 kcal/d. The recommended intake during the study was 1627 ± 37 kcal/d, which represents a reduction of 30.9% ± 2.8% compared with the prestudy intake (P < 0.001). DZX dose and side effects The most frequently reported side effects during dose escalation were transient nausea (n = 11 in the DZX+MTF arm, n = 1 in the DZX+PL and PL+PL arms), loose stools (n = 2 in the DZX+MTF arm and n = 1 in the DZX+PL and PL+PL arms), edema (n = 8 in the DZX+MTF arm, n = 3 in the DZX+PL arm, and n = 1 in the PL+PL arm), hypertrichosis (n = 2 in both DZX arms and n = 1 in the PL+PL arm), and palpitations (n = 3 in the DZX+PL arm). The dose-limiting events were hyperglycemia (n = 3 in both DZX arms), edema (n = 8 in the DZX+MTF arm, n = 3 in the DZX+PL arm, and n = 1 in the PL+PL arm), and nausea (n = 1 in both DZX arms). Transient glucosuria was detected in three men at 2, 3, and 5 months, respectively (one in the DZX+PL arm and two in the DZX+MTF arm). All side effects disappeared after dose reduction, and none of the patients had side effects or glucosuria at 6 months. The achieved mean daily DZX dose was 422 ± 62 mg in the DZX+PL arm and 442 ± 34 mg in the DZX+MTF arm (Fig. 2). Only two men reached the maximum dose of 700 mg/d. The plasma DZX levels at 6 months were 37.9 ± 8.8 mg/L and 38.8 ± 5.1 mg/L (P = 0.85), respectively. DZX was not detectable in the PL+PL group. All but one subject tolerated MTF at a dose of 2250 mg/d. Figure 2. View largeDownload slide Mean diazoxide dose (left) and plasma levels (right) during the study in the DZX-MTF arm (black bars and filled circle), DZX-PL arm (open bars and open circle), and PL+PL arm (hexagon). Figure 2. View largeDownload slide Mean diazoxide dose (left) and plasma levels (right) during the study in the DZX-MTF arm (black bars and filled circle), DZX-PL arm (open bars and open circle), and PL+PL arm (hexagon). Effects on serum insulin and glucose levels After 6 months, PL+PL treatment was associated with a 23% reduction in fasting insulin, without a change in glucose levels. DZX treatment reduced fasting insulin levels by >70% (P < 0.001), from 15.5 ± 2.6 to 5.6 ± 1.7 mU/L (P < 0.01) and from 14.6 ± 1.9 to 4.1 ± 09 mU/L (P < 0.001) in the DZX+PL and DZX+MTF groups, respectively. Postmeal peak insulin and area under the curve insulin (AUC)Ins decreased by 67% (Fig. 3). This reduction in insulin levels was associated with a small but significant increase in fasting glucose levels in both DZX groups: 0.7 ± 0.2 mmol/L [95% confidence interval (CI), 0.1 to 1.2] in the DZX+PL arm and 0.6 ± 0.3 mmol/L (95% CI, 0.0 to 1.1) in the DZX+MTF arm (Table 1). Postmeal peak glucose levels increased by 1.5 ± 0.4 and 1.1 ± 0.6 mmol/L, and AUCGluc increased by 16% in both groups. HbA1c increased by 0.3 ± 0.1% (95% CI, 0.0 to 0.7) and 0.2 ± 0.1% (95% CI, 0.0 to 0.4), respectively. Effects on lipids In the PL+PL arm, high-density lipoprotein cholesterol (HDL-C) and LDL-C did not change significantly, whereas triglycerides (TGs) decreased by 14% (P < 0.05). Both DZX groups had significant improvements in TG, HDL-C, and LDL-C levels as compared with PL (P < 0.001). DZX treatment increased HDL-C by 36% and 25%, and plasma (TG) decreased by 58% and 43% in the DZX+PL and DZX+MTF arms, respectively (Fig. 4). LDL-C decreased by 20% in both DZX groups. HDL-C levels were inversely related to fasting insulin levels, AUCins, and HOMA-IR (r = −0.46, r = −0.44, and r = −0.40, respectively; P < 0.001 for all). TG levels were positively correlated with fasting insulin levels (r = 0.23; P = 0.02). Levels of FFA, β-hydroxybutyric acid, and aceto-acetate showed no significant change within or between the three treatment arms (data not shown). Figure 3. View largeDownload slide Serum insulin and glucose responses to a standardized test meal before (open symbols) and after (filled symbols) 6 months of treatment. Figure 3. View largeDownload slide Serum insulin and glucose responses to a standardized test meal before (open symbols) and after (filled symbols) 6 months of treatment. Figure 4. View largeDownload slide Change in plasma TGs, HDL-C, and LDL-C after 6 months in the PL+PL (open bar), DZX+PL (dashed bar), and DZX+MTF (filled bar) arm. *P < 0.05 compared with PL+PL. Figure 4. View largeDownload slide Change in plasma TGs, HDL-C, and LDL-C after 6 months in the PL+PL (open bar), DZX+PL (dashed bar), and DZX+MTF (filled bar) arm. *P < 0.05 compared with PL+PL. Effects on other parameters A PL-subtracted decline in systolic blood pressure of 10.4 mm Hg (P = 0.09) and a PL-subtracted decline in diastolic blood pressure of 6.3 mm Hg (P = 0.19) were observed in the DZX arms. When both DZX arms were combined, the PL-subtracted declines in systolic and diastolic blood pressure reached statistical significance (P = 0.02 and P = 0.05, respectively). No significant changes were observed between the three arms regarding hemoglobin, leukocyte and thrombocyte count, plasma creatinine or electrolyte levels, uric acid, or thyroid and gonadal hormones. In the case of persistent edema (n = 10), NT-pro-BNP levels were measured. Levels ranged from 1 to 18 pmol/L and did not exceed the upper limit of normal (<21 pmol/L). DZX with or without MTF The results of DZX treatment with or without MTF are shown in Table 2. The declines in body weight, blood pressure, and insulin levels and the changes in glucose and lipid levels were of similar magnitude in both groups. MTF use was associated with a slightly lower postmeal peak glucose but had no significant effect on other parameters of glucose control. Gastrointestinal side effects were much more common in patients using DZX+MTF. Table 2. Baseline Characteristics and Changes After 6 Months PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f Abbreviations: BP, blood pressure; ND, not detectable. a Significance of changes within groups: P < 0.001. b P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and DZX+PL vs PL+PL. c Significance of changes within groups: P < 0.01. d Significance of changes within groups: P < 0.05. e P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and PL+PL vs DZX+PL. f P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+PL and PL+PL. View Large Table 2. Baseline Characteristics and Changes After 6 Months PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f PL+PL (n = 12) DZX (all) (n = 12) DZX+PL (n = 9) DZX+MTF (n = 12) P Value Age, y 46.6 ± 1.9 42.3 ± 1.7 41.9 ± 3.1 42.5 ± 2.0 0.29 Intake, kcal/d 2468.4 ± 186.7 2540.1 ± 160.1 2671.2 ± 178.1 2269.3 ± 165.0 0.31 DZX dose, mg/d 435 ± 33 422 ± 62 442 ± 34 0.61 DZX serum level, mg/L ND 37.2 ± 4.7 37.9 ± 8.8 38.8 ± 5.1 0.62 Weight, kg  Baseline 118.5 ± 2.4 119.9 ± 2.9 124.5 ± 4.9 116.7 ± 3.4 0.58  Change −8.3 ± 0.8a −12.4 ± 1.6a −12.3 ± 1.6a −12.4 ± 1.3a 0.03b Systolic BP  Baseline 137.8 ± 4.8 142 ± 2.2 145.8 ± 4.2 138.0 ± 4.7 0.56  Change −1.4 ± 4.3 −11.8 ± 2.7a −15.2 ± 3.7c −9.7 ± 3.7d 0.09 Diastolic BP  Baseline 87.9 ± 3.3 88.2 ± 2.3 86.4 ± 1.7 87.0 ± 2.2 0.97  Change −2.4 ± 3.1 −8.7 ± 2.2d −3.0 ± 3.1 −11.2 ± 2.9d 0.19 HbA1c, %  Baseline 5.5 ± 0.1 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.13  Change 0.0 ± 0.1 0.2 ± 0.1 0.3 ± 0.1 0.2 ± 0.1 0.17 Fasting insulin, mU/L  Baseline 13.1 ± 1.7 15.0 ± 1.5 15.5 ± 2.6 14.6 ± 1.8 0.43  Change −3.4 ± 1.7 −11.5 ± 1.2a −12.5 ± 2.3c −10.8 ± 1.3a <0.01b Peak insulin, mU/L  Baseline 125.3 ± 18.6 119.9 ± 13.7 124.8 ± 24.0 115.5 ± 6.7 0.92  Change −37.2 ± 17.8 −79.9 ± 14.2 −77.3 ± 27.3 −81.9 ± 15.8 0.19 Fasting glucose, mmol/L  Baseline 5.6 ± 0.2 5.7 ± 0.1 5.6 ± 0.1 5.7 ± 0.1 0.53  Change −0.1 ± 0.1 0.6 ± 0.2c 0.7 ± 0.2d 0.6 ± 0.3d 0.04b Peak glucose, mmol/L  Baseline 8.5 ± 0.4 8.5 ± 0.3 8.3 ± 0.4 8.7 ± 0.4 0.81  Change −0.4 ± 0.4 1.2 ± 0.4 1.5 ± 0.4 1.1 ± 0.6 0.01b HOMA-IR  Baseline 3.2 ± 0.4 4.1 ± 0.4 4.5 ± 0.7 3.8 ± 0.5 0.24  Change −0.8 ± 0.5 −2.9 ± 0.3a −3.2 ± 0.6c −2.7 ± 0.4a 0.004b HDL-C, mmol/L  Baseline 1.0 ± 0.1 1.1 ± 0.0 1.1 ± 0.1 1.2 ± 0.1 0.33  Change 0.1 ± 0.1 0.4 ± 0.1a 0.4 ± 0.1a 0.3 ± 0.1a 0.04b LDL-C, mmol/L  Baseline 3.2 ± 0.2 3.4 ± 0.2 3.8 ± 0.3 3.0 ± 0.2 0.03e  Change −0.2 ± 0.2 −0.8 ± 0.2a −0.9 ± 0.4d −0.6 ± 0.1a 0.02f TG, mmol/L  Baseline 2.2 ± 0.4 1.9 ± 0.4 2.4 ± 0.4 1.6 ± 0.3 0.16  Change −0.3 ± 0.1d −1.0 ± 0.2a −1.4 ± 0.4d −0.7 ± 0.2c 0.03f Abbreviations: BP, blood pressure; ND, not detectable. a Significance of changes within groups: P < 0.001. b P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and DZX+PL vs PL+PL. c Significance of changes within groups: P < 0.01. d Significance of changes within groups: P < 0.05. e P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+MTF and PL+PL vs DZX+PL. f P value represents the significance of differences between the three groups as evaluated by analysis of variance: P < 0.05 between DZX+PL and PL+PL. View Large Discussion The present study focused on the safety aspects of DZX as monotherapy or in combination with MTF as a treatment of obesity in nondiabetic men and describes the effects of DZX on glucose and lipid metabolism. DZX treatment for 6 months lowered insulin levels by >70%, compared with a 24% reduction in the PL+PL arm. This decrease in insulin levels was associated with a large improvement in plasma lipid levels at the cost of a small rise in glucose levels. Insulin resistance evaluated by HOMA-IR showed a 70% improvement in insulin sensitivity. Obesity-related hyperinsulinemia is generally viewed as a compensatory β-cell response to overcome the resistance to the glucose-lowering actions of insulin. However, sustained hyperinsulinism can also cause insulin resistance by a decline in insulin receptors and/or postreceptor defects (14–17). In contrast, forced DZX-mediated insulin suppression has been shown to increase insulin sensitivity in animals and in humans (8, 18). The marked improvement in insulin sensitivity explains why a 70% decrease in insulin levels did not lead to overt diabetes mellitus but only caused mild glucose intolerance. It is conceivable that glucose intolerance as a result of forced insulin lowering can be avoided by individualized DZX dose adjustment. The main aim of the current study was to find the optimal DZX dose to achieve maximal insulin suppression without causing metabolic harm that would outweigh the beneficial effects of weight loss. At 6 months, fasting glucose levels had increased slightly in the DZX+PL group as compared with the PL+PL arm. Fasting glucose levels >5.0 mmol/L are associated with a higher risk for cardiovascular disease. The hazard ratio adjusted for age, smoking status, alcohol, exercise, BMI, and systolic blood pressure in men with a fasting glucose level between 6.1 and 6.4 mmol/L is 5% to 12% higher when compared with a fasting glucose of 5 mmol/L (19, 20). To determine the total cost/benefit ratio, the adverse effects on glucose metabolism should be weighed against the beneficial effects on lipid levels and blood pressure. Compared with the PL+PL group, DZX caused a fourfold increase in HDL-C and a fourfold higher decline in LDL-C and TG levels, which has been shown to substantially reduce the risk of cardiovascular disease (21, 22). In addition, the PL-subtracted 10 mm Hg decline in systolic blood pressure may have a positive effect on cardiovascular risk (23). The improvements in blood pressure and lipid levels are likely to outweigh the risks associated with a modest deterioration in glucose metabolism. These expectations are supported by findings in recent rodent studies demonstrating that insulin lowering had no prolonged adverse effects on glucose homeostasis but was associated with reduced adiposity and substantial lifespan extension (24). The design of the current study included a treatment arm with the combination of DZX and MTF. MTF was added to reduce the risk of hyperglycemia and because of its potential effects on weight loss (25–28). PL-controlled trials in obese hyperinsulinemic adolescents or adults without diabetes have shown that MTF at 1000 to 1700 mg/d for 2 to 6 months induces a 3-kg PL-subtracted weight loss and an increase in insulin sensitivity (26–28). In our study, adding MTF to DZX did not increase weight loss, had no protective effect on fasting and peak glucose levels, and had no additional beneficial effects on lipid levels. The beneficial effects of DZX on lipid levels were in line with expectations based on previous observations documenting the central role of insulin in the control of lipid metabolism and body fat mass (16, 29–31). Insulin suppresses intracellular lipolysis by inhibition of the adipocyte’s hormone-sensitive lipase, promotes hepatic and adipocyte lipogenesis by increasing FFA uptake by stimulation of lipoprotein lipase–mediated release of FFA from lipoprotein TGs, and increases glycerol-3 phosphate availability by stimulation of glucose uptake (16, 30–32). The reverse occurs with DZX-mediated insulin suppression. The decline in plasma TGs and LDL-C is due to decreased production and increased catabolism of TG-rich lipoproteins, and the rise in HDL-C can be attributed to a decrease in HDL-C catabolism (31, 32). Hyperglycemia and edema were the main dose-limiting effects of DZX treatment. Both effects disappeared after dose reduction. Edema was not related to changes in plasma albumin. The minor decrease in albumin levels during DZX treatment (–1.2 ± 0.7 g/L for both DZX arms; P = 0.43) was too small to explain the onset of edema. DZX is known to produce vasodilation and causes sodium and water retention that is probably secondary to the decrease in intravascular pressure (33, 34). Increased capillary permeability might be an additional explanation. We found no evidence of congestive heart failure. NT-pro-BNP levels were well within the normal range. Our study has limitations. Because of its small numbers, it should be regarded as an explorative study that requires confirmation by larger studies. Furthermore, the present data cannot be extrapolated to women. It appears that women are more sensitive to the insulin-suppressive effects of DZX than men (9). In summary, DZX treatment, combined with increased physical exercise and moderate caloric restriction, reduces insulin levels by 70% without causing major increases in glucose levels and has beneficial effects on lipid levels and blood pressure. The large interindividual variation in maximal tolerated dose of DZX underscores the need for individualized dose titration. The main dose-limiting effects were hyperglycemia and edema; both were reversible after dose reduction. Abbreviations: Abbreviations: AUC area under the curve BMI body mass index CI confidence interval DZX diazoxide FFA free fatty acid HbA1c hemoglobin A1C HDL-C high-density lipoprotein cholesterol HOMA-IR homeostatic model assessment of insulin resistance LDL-C low-density lipoprotein cholesterol MTF metformin NT-pro-BNP N-terminal prohormone of brain natriuretic peptide PL placebo TG triglyceride Acknowledgments Clinical Trial Information: ClinicalTrials.gov no. NCT00631033 (registered November 2004). Current Affiliation: S. Loves’ current affiliation is Treant Health Care Group, 7824 AA Emmen, Boermarkeweg 60, The Netherlands. Disclosure Summary: The authors have nothing to disclose. References 1. Polonsky KS , Given BD , Van Cauter E . Twenty-four-hour profiles and pulsatile patterns of insulin secretion in normal and obese subjects . J Clin Invest . 1988 ; 81 ( 2 ): 442 – 448 . Google Scholar CrossRef Search ADS PubMed 2. Le Stunff C , Bougnères P . Early changes in postprandial insulin secretion, not in insulin sensitivity, characterize juvenile obesity . Diabetes . 1994 ; 43 ( 5 ): 696 – 702 . Google Scholar CrossRef Search ADS PubMed 3. Cusin I , Terrettaz J , Rohner-Jeanrenaud F , Jeanrenaud B . Metabolic consequences of hyperinsulinaemia imposed on normal rats on glucose handling by white adipose tissue, muscles and liver . Biochem J . 1990 ; 267 ( 1 ): 99 – 103 . Google Scholar CrossRef Search ADS PubMed 4. Rizza RA , Mandarino LJ , Genest J , Baker BA , Gerich JE . Production of insulin resistance by hyperinsulinaemia in man . Diabetologia . 1985 ; 28 ( 2 ): 70 – 75 . Google Scholar PubMed 5. Arner P , Bolinder J , Engfeldt P , Hellmér J , Ostman J . Influence of obesity on the antilipolytic effect of insulin in isolated human fat cells obtained before and after glucose ingestion . J Clin Invest . 1984 ; 73 ( 3 ): 673 – 680 . Google Scholar CrossRef Search ADS PubMed 6. Howard BV , Klimes I , Vasquez B , Brady D , Nagulesparan M , Unger RH . The antilipolytic action of insulin in obese subjects with resistance to its glucoregulatory action . J Clin Endocrinol Metab . 1984 ; 58 ( 3 ): 544 – 548 . Google Scholar CrossRef Search ADS PubMed 7. Templeman NM , Skovsø S , Page MM , Lim GE , Johnson JD . A causal role for hyperinsulinemia in obesity . J Endocrinol . 2017 ; 232 ( 3 ): R173 – R183 . Google Scholar CrossRef Search ADS PubMed 8. Alemzadeh R , Langley G , Upchurch L , Smith P , Slonim AE . Beneficial effect of diazoxide in obese hyperinsulinemic adults . J Clin Endocrinol Metab . 1998 ; 83 ( 6 ): 1911 – 1915 . Google Scholar PubMed 9. Schreuder T , Karreman M , Rennings A , Ruinemans-Koerts J , Jansen M , de Boer H . Diazoxide-mediated insulin suppression in obese men: a dose-response study . Diabetes Obes Metab . 2005 ; 7 ( 3 ): 239 – 245 . Google Scholar CrossRef Search ADS PubMed 10. van Boekel G , Loves S , van Sorge A , Ruinemans-Koerts J , Rijnders T , de Boer H . Weight loss in obese men by caloric restriction and high-dose diazoxide-mediated insulin suppression . Diabetes Obes Metab . 2008 ; 10 ( 12 ): 1195 – 1203 . Google Scholar PubMed 11. Lewis GF , Carpentier A , Adeli K , Giacca A . Disordered fat storage and mobilization in the pathogenesis of insulin resistance and type 2 diabetes . Endocr Rev . 2002 ; 23 ( 2 ): 201 – 229 . Google Scholar CrossRef Search ADS PubMed 12. Harris JA , Benedict FG . A biometric study of human basal metabolism on men . Proc Natl Acad Sci USA . 1918 ; 4 ( 12 ): 370 – 373 . Google Scholar CrossRef Search ADS PubMed 13. Matthews DR , Hosker JP , Rudenski AS , Naylor BA , Treacher DF , Turner RC . Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man . Diabetologia . 1985 ; 28 ( 7 ): 412 – 419 . Google Scholar CrossRef Search ADS PubMed 14. Shanik MH , Xu Y , Skrha J , Dankner R , Zick Y , Roth J . Insulin resistance and hyperinsulinemia: is hyperinsulinemia the cart or the horse ? Diabetes Care . 2008 ; 31 ( Suppl 2 ): S262 – S268 . Google Scholar CrossRef Search ADS PubMed 15. Koopmans SJ , Ohman L , Haywood JR , Mandarino LJ , DeFronzo RA . Seven days of euglycemic hyperinsulinemia induces insulin resistance for glucose metabolism but not hypertension, elevated catecholamine levels, or increased sodium retention in conscious normal rats . Diabetes . 1997 ; 46 ( 10 ): 1572 – 1578 . Google Scholar CrossRef Search ADS PubMed 16. Samuel VT , Shulman GI . The pathogenesis of insulin resistance: integrating signaling pathways and substrate flux . J Clin Invest . 2016 ; 126 ( 1 ): 12 – 22 . Google Scholar CrossRef Search ADS PubMed 17. Wigand JP , Blackard WG . Downregulation of insulin receptors in obese man . Diabetes . 1979 ; 28 ( 4 ): 287 – 291 . Google Scholar CrossRef Search ADS PubMed 18. Alemzadeh R , Jacobs W , Pitukcheewanont P . Antiobesity effect of diazoxide in obese Zucker rats . Metabolism . 1996 ; 45 ( 3 ): 334 – 341 . Google Scholar CrossRef Search ADS PubMed 19. Park C , Guallar E , Linton JA , Lee DC , Jang Y , Son DK , Han EJ , Baek SJ , Yun YD , Jee SH , Samet JM . Fasting glucose level and the risk of incident atherosclerotic cardiovascular diseases . Diabetes Care . 2013 ; 36 ( 7 ): 1988 – 1993 . Google Scholar CrossRef Search ADS PubMed 20. Sung J , Song YM , Ebrahim S , Lawlor DA . Fasting blood glucose and the risk of stroke and myocardial infarction . Circulation . 2009 ; 119 ( 6 ): 812 – 819 . Google Scholar CrossRef Search ADS PubMed 21. Gordon DJ , Probstfield JL , Garrison RJ , Neaton JD , Castelli WP , Knoke JD , Jacobs DR Jr , Bangdiwala S , Tyroler HA . High-density lipoprotein cholesterol and cardiovascular disease. Four prospective American studies . Circulation . 1989 ; 79 ( 1 ): 8 – 15 . Google Scholar CrossRef Search ADS PubMed 22. Baigent C , Keech A , Kearney PM , Blackwell L , Buck G , Pollicino C , Kirby A , Sourjina T , Peto R , Collins R , Simes R ; Cholesterol Treatment Trialists’ (CTT) Collaborators . Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90,056 participants in 14 randomised trials of statins . Lancet . 2005 ; 366 ( 9493 ): 1267 – 1278 . Google Scholar CrossRef Search ADS PubMed 23. Borghi C , Dormi A , L’Italien G , Lapuerta P , Franklin SS , Collatina S , Gaddi A . The relationship between systolic blood pressure and cardiovascular risk: results of the Brisighella Heart Study . J Clin Hypertens (Greenwich) . 2003 ; 5 ( 1 ): 47 – 52 . Google Scholar CrossRef Search ADS PubMed 24. Templeman NM , Flibotte S , Chik JHL , Sinha S , Lim GE , Foster LJ , Nislow C , Johnson JD . Reduced circulating insulin enhances insulin sensitivity in old mice and extends lifespan . Cell Reports . 2017 ; 20 ( 2 ): 451 – 463 . Google Scholar CrossRef Search ADS PubMed 25. Aroda VR , Knowler WC , Crandall JP , Perreault L , Edelstein SL , Jeffries SL , Molitch ME , Pi-Sunyer X , Darwin C , Heckman-Stoddard BM , Temprosa M , Kahn SE , Nathan DM ; Diabetes Prevention Program Research Group . Metformin for diabetes prevention: insights gained from the Diabetes Prevention Program/Diabetes Prevention Program Outcomes Study . Diabetologia . 2017 ; 60 ( 9 ): 1601 – 1611 . Google Scholar CrossRef Search ADS PubMed 26. Kay JP , Alemzadeh R , Langley G , D’Angelo L , Smith P , Holshouser S . Beneficial effects of metformin in normoglycemic morbidly obese adolescents . Metabolism . 2001 ; 50 ( 12 ): 1457 – 1461 . Google Scholar CrossRef Search ADS PubMed 27. Atabek ME , Pirgon O . Use of metformin in obese adolescents with hyperinsulinemia: a 6-month, randomized, double-blind, placebo-controlled clinical trial . J Pediatr Endocrinol Metab . 2008 ; 21 ( 4 ): 339 – 348 . Google Scholar CrossRef Search ADS PubMed 28. Stumvoll M , Nurjhan N , Perriello G , Dailey G , Gerich JE . Metabolic effects of metformin in non-insulin-dependent diabetes mellitus . N Engl J Med . 1995 ; 333 ( 9 ): 550 – 554 . Google Scholar CrossRef Search ADS PubMed 29. Olefsky JM , Farquhar JW , Reaven GM . Reappraisal of the role of insulin in hypertriglyceridemia . Am J Med . 1974 ; 57 ( 4 ): 551 – 560 . Google Scholar CrossRef Search ADS PubMed 30. Farese RV Jr , Yost TJ , Eckel RH . Tissue-specific regulation of lipoprotein lipase activity by insulin/glucose in normal-weight humans . Metabolism . 1991 ; 40 ( 2 ): 214 – 216 . Google Scholar CrossRef Search ADS PubMed 31. Vergès B . Pathophysiology of diabetic dyslipidaemia: where are we ? Diabetologia . 2015 ; 58 ( 5 ): 886 – 899 . Google Scholar CrossRef Search ADS PubMed 32. Czech MP , Tencerova M , Pedersen DJ , Aouadi M . Insulin signalling mechanisms for triacylglycerol storage . Diabetologia . 2013 ; 56 ( 5 ): 949 – 964 . Google Scholar CrossRef Search ADS PubMed 33. van Hamersvelt HW , Kloke HJ , de Jong DJ , Koene RA , Huysmans FT . Oedema formation with the vasodilators nifedipine and diazoxide: direct local effect or sodium retention ? J Hypertens . 1996 ; 14 ( 8 ): 1041 – 1045 . Google Scholar CrossRef Search ADS PubMed 34. Koch-Weser J . Diazoxide . N Engl J Med . 1976 ; 294 ( 23 ): 1271 – 1273 . Copyright © 2018 Endocrine Society

Journal

Journal of Clinical Endocrinology and MetabolismOxford University Press

Published: Mar 29, 2018

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