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Exercise and insulin cause GLUT-4 translocation in human skeletal muscle

Exercise and insulin cause GLUT-4 translocation in human skeletal muscle Abstract Studies in rodents have established that GLUT-4 translocation is the major mechanism by which insulin and exercise increase glucose uptake in skeletal muscle. In contrast, much less is known about the translocation phenomenon in human skeletal muscle. In the current study, nine healthy volunteers were studied on two different days. On one day, biopsies of vastus lateralis muscle were taken before and after a 2-h euglycemic-hyperinsulinemic clamp (0.8 mU ⋅ kg −1 ⋅ min −1 ). On another day, subjects exercised for 60 min at 70% of maximal oxygen consumption (V˙ o 2 max ), a biopsy was obtained, and the same clamp and biopsy procedure was performed as that during the previous experiment. Compared with insulin treatment alone, glucose infusion rates were significantly increased during the postexercise clamp for the periods 0–30 min, 30–60 min, and 60–90 min, but not during the last 30 min of the clamp. Plasma membrane GLUT-4 content was significantly increased in response to physiological hyperinsulinemia (32% above rest), exercise (35%), and the combination of exercise plus insulin (44%). Phosphorylation of Akt, a putative signaling intermediary for GLUT-4 translocation, was increased in response to insulin (640% above rest), exercise (280%), and exercise plus insulin (1,000%). These data demonstrate that two normal physiological conditions, moderate intensity exercise and physiological hyperinsulinemia ∼56 μU/ml, cause GLUT-4 translocation and Akt phosphorylation in human skeletal muscle. glucose transporters glucose uptake Akt glucose disposal muscle contraction Footnotes The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. §1734 solely to indicate this fact. Copyright © 1999 the American Physiological Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Endocrinology and Metabolism The American Physiological Society

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Publisher
The American Physiological Society
Copyright
Copyright © 2011 the American Physiological Society
ISSN
0193-1849
eISSN
1522-1555
Publisher site
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Abstract

Abstract Studies in rodents have established that GLUT-4 translocation is the major mechanism by which insulin and exercise increase glucose uptake in skeletal muscle. In contrast, much less is known about the translocation phenomenon in human skeletal muscle. In the current study, nine healthy volunteers were studied on two different days. On one day, biopsies of vastus lateralis muscle were taken before and after a 2-h euglycemic-hyperinsulinemic clamp (0.8 mU ⋅ kg −1 ⋅ min −1 ). On another day, subjects exercised for 60 min at 70% of maximal oxygen consumption (V˙ o 2 max ), a biopsy was obtained, and the same clamp and biopsy procedure was performed as that during the previous experiment. Compared with insulin treatment alone, glucose infusion rates were significantly increased during the postexercise clamp for the periods 0–30 min, 30–60 min, and 60–90 min, but not during the last 30 min of the clamp. Plasma membrane GLUT-4 content was significantly increased in response to physiological hyperinsulinemia (32% above rest), exercise (35%), and the combination of exercise plus insulin (44%). Phosphorylation of Akt, a putative signaling intermediary for GLUT-4 translocation, was increased in response to insulin (640% above rest), exercise (280%), and exercise plus insulin (1,000%). These data demonstrate that two normal physiological conditions, moderate intensity exercise and physiological hyperinsulinemia ∼56 μU/ml, cause GLUT-4 translocation and Akt phosphorylation in human skeletal muscle. glucose transporters glucose uptake Akt glucose disposal muscle contraction Footnotes The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. §1734 solely to indicate this fact. Copyright © 1999 the American Physiological Society

Journal

AJP - Endocrinology and MetabolismThe American Physiological Society

Published: Oct 1, 1999

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