Short-term exercise enhances insulin-stimulated GLUT-4 translocation and glucose transport in adipose cells

This investigation examined the effects of short-term exercise training on ea insulin-stimulated GLUT-4 glucose transporter translocation and glucose transport activity in rat adipose cells. Male Wistar rats were randomly ass igned to a sedentary (Sed) or swim training group (Sw, 4 days; final 3 days : 2 x 3 h/day). Adipose cell size decreased significantly but minimally (si milar to 20%), whereas total GLUT-4 increased by 30% in Sw vs. Sed rats. Ba sal 3-O-methyl-D-[C-14]glucose transport was reduced by 62%, whereas maxima lly insulin-stimulated (MIS) glucose transport was increased by 36% in Sw v s. Sed rats. MIS cell surface GLUT-4 photolabeling was 44% higher in the Sw vs. Sed animals, similar to the increases observed in MIS glucose transpor t activity and total GLUT-4. These results suggest that increases in total GLUT-4 and GLUT-4 translocation to the cell surface contribute to the incre ase in MIS glucose transport with short-term exercise training. In addition , the results suggest that the exercise training-induced adaptations in glu cose transport occur more rapidly than previously thought and with minimal changes in adipose cell size.