title: Carbohydrate depletion has profound effects on the muscle amino acid and glucose metabolism during hyperinsulinaemia.
abstract: OBJECTIVE
  We investigated the effect of carbohydrate availability and euglycaemic hyperinsulinaemia on intramuscular and plasma amino acids in 14 healthy men (age 26.5 +/- 0.9 years, b.m.i. 22.9 +/- 0.5 kg/m2).
  
  
  METHODS
  Insulin was infused (1.5 mU/kg/min) for 240 min both after a carbohydrate depleting exercise and after carbohydrate loading. Muscle samples were taken before and after hyperinsulinaemia. Plasma and intramuscular amino acid concentrations were measured.
  
  
  RESULTS
  Insulin-mediated glucose disposal was similar after carbohydrate depletion (65.2 +/- 1.9 micromol/kg/min) and loading (66.9 +/- 2.8 micromol/kg/min). Carbohydrate depletion was associated with decreased alanine and increased branched chain amino acid (BCAA) concentrations in muscle and plasma. Blood lactate was lower after carbohydrate depletion (477 +/- 25 micromol/l) than loading (850 +/- 76 micromol/l, p < 0.001). In carbohydrate depletion, hyperinsulinaemia resulted in a greater increase in intramuscular (from 927 +/- 48 nmol/g muscle to 2029 +/- 104 nmol/g muscle, p < 0.001), than plasma (from 197 +/- 6.7 micromol/l to 267 +/- 11 micromol/l, p < 0.001) alanine. After carbohydrate loading muscle alanine did not rise significantly (from 1546 +/- 112 nmol/g muscle to 1781 +/- 71 nmol/g muscle) whereas plasma alanine decreased (from 339 +/- 26 micromol/l to 272 +/- 13 micromol/l, p < 0.05).
  
  
  CONCLUSIONS
  (1) Carbohydrate availability has profound effects on the interrelationship between glucose and amino acid metabolism and on the form of storage for glucose-derived carbons. (2) For most amino acids changes in plasma levels of amino acids are not related to changes in concentrations of intramuscular amino acids during hyperinsulinaemia.
authors: Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland. pertti_ebeling@yahoo.com
authors: P
authors: P
authors: Ebeling
authors: J A
authors: JA
authors: Tuominen
authors: M L
authors: ML
authors: Laipio
authors: M A
authors: MA
authors: Virtanen
authors: E
authors: E
authors: Koivisto
authors: V A
authors: VA
authors: Koivisto
mesh_terms: D000328:Adult; D000409:Alanine / Q000097:blood / Q000378:metabolism; D000596:Amino Acids / Q000097:blood / Q000378:metabolism*; D000597:Amino Acids, Branched-Chain / Q000097:blood / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D002241:Carbohydrates / Q000172:deficiency*; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D006946:Hyperinsulinism / Q000378:metabolism*; D007328:Insulin / Q000008:administration & dosage; D019344:Lactic Acid / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D002241:Carbohydrates; D004040:Dietary Carbohydrates; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D019344:Lactic Acid; D005947:Glucose; D000409:Alanine