EFFECT OF ELECTRICAL-STIMULATION PATTERNS ON GLUCOSE-TRANSPORT IN RATMUSCLES

Transport of 2-[H-3]deoxy-D-glucose (2-DG) was investigated during sup ramaximal stimulations of different muscles. In addition, we varied th e net stimulation time (NST). In different treatments, NST occupied ei ther 5, 7.5, 10, 15, 20, 30, or 50% of a 20-min stimulation period. Af ter a bolus injection of H-3-labeled 2-DG, the greatest transport occu rred in the extensor digitorum long-us. In red gastrocnemius (RG; type IIa fibers) and white gastrocnemius (WG; type IIb fibers), the 2-DG t ransport rate was highest at 10% NST (8- to 12-fold increase) and decr eased thereafter. In soleus (type I fibers), the 2-DG transport increa sed from 5 to 50% NST Below 30% NST, 2-DG transport was greater in RG and WG muscles than in soleus (P < 0.05). GLUT-4 and 2-DG transport we re not correlated during the contractions. Therefore, the percent NST affects 2-DG transport differentially in muscles of varying fiber type s, and the transport rate is not related to the GLUT-4 content of the muscles.