No accumulation of glucose in human skeletal muscle during euglycemic hyperinsulinemia.

Abstract

It has been recently suggested that high glucose infusion rates during euglycemic hyperinsulinemia result in accumulation of free glucose in human skeletal muscle (J. Clin. Invest. 76: 357, 1985). To examine this possibility, we performed a euglycemic, hyperinsulinemic clamp together with biopsies from the quadriceps femoris muscle on seven healthy men. Insulin was infused at successive rates of 40 and 400 mU. m-2.min-1, resulting in mean plasma insulin concentrations of 69 +/- 3 and 1,285 +/- 115 (SE) microU/ml, respectively. Glucose infusion rates averaged 7.79 +/- 0.86 and 12.01 +/- 0.77 mg.kg body wt-1.min-1. The total glucose content in muscle averaged 1.72 +/- 0.26, 1.37 +/- 0.21, and 1.65 +/- 0.35 mmol/kg dry wt at rest, and after the low- and high-dose insulin infusions, respectively (P greater than 0.05). Assuming that the plasma glucose concentration reflects the glucose concentration in the extracellular space and that there are 0.3 liters of extracellular water per kilogram dry weight, the intracellular glucose contents are calculated to be 0.15 +/- 0.25, -0.35 +/- 0.21, and -0.06 +/- 0.34 mmol/kg dry wt at rest, and after the low- and high-dose infusions, respectively. None of these values is significantly different from zero. Thus euglycemic hyperinsulinemia does not result in appreciable accumulation of glucose in the muscle of insulin-sensitive men.