INFLUENCE OF INSULIN ON PERIPHERAL UPTAKE OF BRANCHED-CHAIN AMINO-ACIDS IN THE 60-HOUR FASTED STATE

The influence of insulin on branched chain amino acid (BCAA) metabolis m was investigated in healthy subjects fasted for 60-64 h, using the e uglycemic insulin clamp technique and hepatic venous catheterization. As compared to the postabsorptive state, fasting resulted in a 50-80% decrease in glucose disposal during the clamps, indicating insulin res istance. However, the arterial concentrations of BCAA, which were incr eased by 200-220% after the fast, decreased to a similar extent during hyperinsulinemia, regardless of the fasting situation. The splanchnic exchange of BCAA was unaltered both in response to fasting itself and to fasting and hyperinsulinemia. The results suggest that insulin res istance during fasting does not influence BCAA metabolism. Furthermore , the changes in BCAA concentrations after a prolonged fast are due to altered peripheral metabolism of BCAA.