Effect of glucose and insulin on triacylglycerol metabolism in isolated normal and diabetic skeletal muscle.

The effects of insulin and glucose on triacylglycerol (TG) metabolism in normal and diabetic isolated skeletal muscle were investigated in this study. Intracellular TG was continuously synthesized and hydrolyzed in both normal and diabetic skeletal muscle. In the absence of insulin and glucose, normal and diabetic skeletal muscle TG content and synthesis were decreased. In contrast, in the presence of insulin and glucose, the normal and diabetic TG contents were unchanged and triacylglycerol synthesis was increased as compared with the respective control values. However, insulin and glucose increased intramuscular TG content to a greater extent than could be accounted for by their stimulation of TG synthesis, indicating that insulin and glucose appear to inhibit TG hydrolysis in diabetic muscle, as well as in normal muscle. In addition, these data suggest that diabetes causes a defect in the ability of insulin and glucose to stimulate TG synthesis, as the increase in diabetic muscle TG synthesis in the presence of insulin and glucose was less than in normal muscle.