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Interrelationships between the renin-angiotensin-aldosterone and calcium homeostatic systems

Interrelationships between the renin-angiotensin-aldosterone and calcium homeostatic systems Abstract Blood pressure is affected by both sodium and calcium intake. To determine if there is an interaction between the regulatory mechanisms for these two cations, eight normal male volunteers received the following 1-h infusions on three different days: 1) angiotensin II (AII), 2) the synthetic 1-34 amino terminal fragment of human PTH [hPTH(1-34)], and 3) AII and hPTH(1-34) together. Blood samples were obtained at t = 0 and every 20 min during each infusion and urine was collected for 3 h both before and after the start of each infusion. Infusion of AII produced an increase in intact PTH from 18 +/- 2 to 31 +/- 4 ng/L (P < 0.05), most likely in response to a small decrease in serum ionized calcium (1.25 +/- 0.01 to 1.23 +/- 0.01 mmol/L, P < 0.05). Urinary excretion of calcium was unchanged. Infusion of hPTH(1-34) at 200 U/h increased N-terminal PTH levels (18 +/- 3 to 268 +/- 42 ng/L, P < 0.05), decreased tubular reabsorption of phosphate (0.92 +/- 0.03 to 0.82 +/- 0.11, P < 0.05), and increased urinary cAMP (0.18 +/- 0.02 to 0.53 +/- 0.05 nmol/L of glomerular filtrate, P = 0.0001). hPTH(1-34) infusion suppressed endogenous intact PTH (18 +/- 3 to 14 +/- 2 ng/L, P < 0.005) and increased PRA from 0.14 +/- 0.02 to 0.32 +/- 0.05 ng/(L.s) (P < 0.05) without a change in serum ionized calcium which suggests direct effects of hPTH(1-34) on the parathyroid glands and the juxtaglomerular apparatus. The effects of AII and hPTH(1-34) were antagonistic with little change in serum ionized calcium, intact PTH, or PRA when both were infused together. These interrelationships between the major hormonal systems controlling sodium and calcium homeostasis suggest a mechanism underlying the close association of calcium and sodium in the regulation of blood pressure. This content is only available as a PDF. Copyright © 1992 by The Endocrine Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Clinical Endocrinology and Metabolism Oxford University Press

Interrelationships between the renin-angiotensin-aldosterone and calcium homeostatic systems

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References (22)

Publisher
Oxford University Press
Copyright
Copyright © 1992 by The Endocrine Society
ISSN
0021-972X
eISSN
1945-7197
DOI
10.1210/jcem.75.4.1400892
Publisher site
See Article on Publisher Site

Abstract

Abstract Blood pressure is affected by both sodium and calcium intake. To determine if there is an interaction between the regulatory mechanisms for these two cations, eight normal male volunteers received the following 1-h infusions on three different days: 1) angiotensin II (AII), 2) the synthetic 1-34 amino terminal fragment of human PTH [hPTH(1-34)], and 3) AII and hPTH(1-34) together. Blood samples were obtained at t = 0 and every 20 min during each infusion and urine was collected for 3 h both before and after the start of each infusion. Infusion of AII produced an increase in intact PTH from 18 +/- 2 to 31 +/- 4 ng/L (P < 0.05), most likely in response to a small decrease in serum ionized calcium (1.25 +/- 0.01 to 1.23 +/- 0.01 mmol/L, P < 0.05). Urinary excretion of calcium was unchanged. Infusion of hPTH(1-34) at 200 U/h increased N-terminal PTH levels (18 +/- 3 to 268 +/- 42 ng/L, P < 0.05), decreased tubular reabsorption of phosphate (0.92 +/- 0.03 to 0.82 +/- 0.11, P < 0.05), and increased urinary cAMP (0.18 +/- 0.02 to 0.53 +/- 0.05 nmol/L of glomerular filtrate, P = 0.0001). hPTH(1-34) infusion suppressed endogenous intact PTH (18 +/- 3 to 14 +/- 2 ng/L, P < 0.005) and increased PRA from 0.14 +/- 0.02 to 0.32 +/- 0.05 ng/(L.s) (P < 0.05) without a change in serum ionized calcium which suggests direct effects of hPTH(1-34) on the parathyroid glands and the juxtaglomerular apparatus. The effects of AII and hPTH(1-34) were antagonistic with little change in serum ionized calcium, intact PTH, or PRA when both were infused together. These interrelationships between the major hormonal systems controlling sodium and calcium homeostasis suggest a mechanism underlying the close association of calcium and sodium in the regulation of blood pressure. This content is only available as a PDF. Copyright © 1992 by The Endocrine Society

Journal

Journal of Clinical Endocrinology and Metabolism – Oxford University Press

Published: Oct 1, 1992

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