Carbohydrate depletion has profound effects on the muscle amino acid and glucose metabolism during hyperinsulinaemia

SUMMARY Aim 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 μmol/kg/min) and loading (66.9 ± 2.8 μmol/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 μmol/l) than loading (850 ± 76 μmol/l, p