BLOOD-FLOW AND GLUCOSE-UPTAKE IN DENERVATED, INSULIN-RESISTANT MUSCLES

To investigate whether changes in blood flow contribute to the insulin resistance in denervated muscles, basal and insulin-stimulated 2-deox y-D-glucose (2-DG) uptake in vivo and blood flow were measured in sole us (slow twitch), plantaris (fast twitch), and gastrocnemius (fast twi tch) muscles at 1 and 3 days after a right hindlimb denervation in the rat. Muscles of the contralateral sham hindlimb served as an internal control. Sham plantaris and gastrocnemius muscles showed 32 and 60% l ower basal 2-DG uptake, 46 and 66% lower insulin-stimulated 2-DG uptak e, and 79 and 81% lower blood flow, respectively, compared with sham s oleus muscle. At 1 day after denervation, soleus, plantaris, and gastr ocnemius muscles exhibited an 80, 64, and 42% decrease in insulin-stim ulated 2-DG uptake, respectively, in the presence of 63, 323, and 304% higher blood flow, respectively. At 3 days after denervation, soleus muscle showed a 60% decrease in basal 2-DG uptake, complete unresponsi veness to insulin, and an 86% decrease in blood flow. In contrast, the denervated plantaris and gastrocnemius muscles exhibited a 262 and 10 5% increase in basal 2-DG uptake, respectively, no change in insulin-s timulated 2-DC uptake, and no change in blood flow compared with corre sponding contralateral sham muscles. The results demonstrate that musc le blood flow is influenced by muscle fiber population and time after denervation and that changes in blood flow do not contribute to the in sulin resistance in the denervated muscles.