Glucose Uptake in Muscle Cell Cultures from Endurance-Trained Men

Abstract

To examine noninsulin- (basal) and insulin-mediated glucose uptake in human skeletal muscle cells from endurance-trained and sedentary individuals. Muscle biopsies (vastus lateralis) were obtained from competitive, endurance-trained athletes (N=12; VO2peak 64.9+/-2.3 mL.kg-1.min-1) and their sedentary counterparts (N=8; VO2peak 51.8+/-2.2 mL.kg-1.min-1), and isolated satellite cells allowed to proceed to myotubes. The myotubes exhibited a dose response for glucose uptake with increasing insulin concentrations; maximal glucose uptake was approximately 1.5-fold over basal. In relation to exercise training status, basal glucose uptake was significantly (P<0.05) elevated by approximately 75% in the endurance-trained versus sedentary men (20.1+/-2.1 vs 11.9+/-1.9 pmol.mg protein-1.min-1, respectively). This difference persisted at insulin concentrations of 10 and 1000 etaM, although the relative increase in insulin-mediated glucose uptake (fold increase over basal) did not differ between the sedentary and endurance-trained cells. These data suggest that cultured skeletal muscle cells from endurance-trained athletes may differ in respect to basal glucose uptake.