title: Effects of acute exposure to increased plasma branched-chain amino acid concentrations on insulin-mediated plasma glucose turnover in healthy young subjects.
abstract: BACKGROUND
  Plasma 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.
  
  
  OBJECTIVE
  To determine the effects of acute exposure to increased plasma BCAA concentrations on insulin-mediated plasma glucose turnover in humans.
  
  
  METHODS
  Ten 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.
  
  
  RESULTS
  Insulin 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).
  
  
  CONCLUSIONS
  Short-term exposure of young healthy subjects to increased plasma BCAA concentrations does not alter the insulin sensitivity of glucose metabolism.
authors.affiliation: Center for Metabolic and Vascular Biology, Arizona State University/Mayo Clinic in Arizona, Scottsdale, Arizona, United States of America.
authors.forename: Sarah
authors.initials: S
authors.lastname: Everman
authors.affiliation: Center for Metabolic and Vascular Biology, Arizona State University/Mayo Clinic in Arizona, Scottsdale, Arizona, United States of America; School of Life Sciences, Arizona State University,Tempe, Arizona, United States of America.
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Mandarino
authors.affiliation: Department of Physiology, Midwestern University, Glendale, Arizona, United States of America.
authors.forename: Chad C
authors.initials: CC
authors.lastname: Carroll
authors.affiliation: Center for Metabolic and Vascular Biology, Arizona State University/Mayo Clinic in Arizona, Scottsdale, Arizona, United States of America; School of Life Sciences, Arizona State University,Tempe, Arizona, United States of America.
authors.forename: Christos S
authors.initials: CS
authors.lastname: Katsanos
mesh_terms: D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000008:administration & dosage*; D001786:Blood Glucose / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000008:administration & dosage*; D008297:Male
chemical_list: D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D007328:Insulin