Effects of Acute Exposure to Increased Plasma Branched-Chain Amino Acid Concentrations on Insulin-Mediated Plasma Glucose Turnover in Healthy Young Subjects |
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Authors: | Sarah Everman Lawrence J Mandarino Chad C Carroll Christos S Katsanos |
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Institution: | 1. Center for Metabolic and Vascular Biology, Arizona State University/Mayo Clinic in Arizona, Scottsdale, Arizona, United States of America.; 2. School of Life Sciences, Arizona State University,Tempe, Arizona, United States of America.; 3. Department of Physiology, Midwestern University, Glendale, Arizona, United States of America.; INSERM/UMR 1048, FRANCE, |
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Abstract: | BackgroundPlasma branched-chain amino acids (BCAA) are inversely related to insulin sensitivity of glucose metabolism in humans. However, currently, it is not known whether there is a cause-and-effect relationship between increased plasma BCAA concentrations and decreased insulin sensitivity.ObjectiveTo determine the effects of acute exposure to increased plasma BCAA concentrations on insulin-mediated plasma glucose turnover in humans.MethodsTen healthy subjects were randomly assigned to an experiment where insulin was infused at 40 mU/m2/min (40U) during the second half of a 6-hour intravenous infusion of a BCAA mixture (i.e., BCAA; N = 5) to stimulate plasma glucose turnover or under the same conditions without BCAA infusion (Control; N = 5). In a separate experiment, seven healthy subjects were randomly assigned to receive insulin infusion at 80 mU/m2/min (80U) in association with the above BCAA infusion (N = 4) or under the same conditions without BCAA infusion (N = 3). Plasma glucose turnover was measured prior to and during insulin infusion.ResultsInsulin infusion completely suppressed the endogenous glucose production (EGP) across all groups. The percent suppression of EGP was not different between Control and BCAA in either the 40U or 80U experiments (P > 0.05). Insulin infusion stimulated whole-body glucose disposal rate (GDR) across all groups. However, the increase (%) in GDR was not different median (1st quartile – 3rd quartile)] between Control and BCAA in either the 40U (199 (167–278) vs. 186 (94–308)] or 80 U (491 (414–548) vs. 478 (409–857)] experiments (P > 0.05). Likewise, insulin stimulated the glucose metabolic clearance in all experiments (P < 0.05) with no differences between Control and BCAA in either of the experiments (P > 0.05).ConclusionShort-term exposure of young healthy subjects to increased plasma BCAA concentrations does not alter the insulin sensitivity of glucose metabolism. |
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