Effect Of Exercise On Glucose Transporter 4 In Adipocyte Of Rats With Insulin Resistance

Background and Objective: Insulin resistance is one of important pathological characters in type 2 diabetes mellitus, which may take place in many links such as pro-receptor, receptor and post-receptor. Signal transduction will cause a series of reactions in intracellular when insulin and corresponding receptor are combined in plasma membrane. Some recent researches manifested that the expression and translocation of glucose transporter 4 (GLUT4) were the key to appellant reactions in intracellular. In our research rats were fed with the high-energy diets to induce insulin resistance and then subject to swim for treatment. Comparing the expression and translocation of GLUT4 in the two conditions, we investigated the effect of exercise on expression and translocation of GLUT4 in adipocyte of rats with insulin resistance and the relations between GLUT4 and insulin resistance.Methods: Experimental rats were randomized into there groups: a control group (n=10), a model group (n=10) and an exercise group (n=10). The model and exercise group were fed with the diets enriched with sucrose (20%, w/w), lard (10%, w/w), cholesterol (2.5%, w/w) and cholic acid (1%, w/w) to induce insulin resistance. The exercise group was subject to swim for 6 weeks. After the plasma membranes and the intracellular membranes of adipocyte were prepared and separated, GLUT4 protein was detected by Western blot analysis. Body weight, serum triglyceride and cholesterol, fasting plasma glucose and serum insulin concentration were detected termly. And the insulin sensitivity index was also calculated.Results: (1) Intracellular membranes GLUT4 protein in adipocyte of the model group rats decreased by 38.72% (p<0.05) and plasma membranes GLUT4 protein decreased by 21.91% (p<0.05) as compared with those of the control group rats. (2) Intracellular membranes GLUT4 protein of the exercise group rats did not change and plasma membranes GLUT4 protein increased 14.01% (p<0.05) as compared with that of the model group rats. (3) Intracellular membranes GLUT4 protein of the exercise group rats decreased by 41.67% (p<0.05) and plasma membranes GLUT4 protein decreased by 7.90% (p<0.05) as compared with those of the control group rats.Conclusion: Diets enriched with sugar and fattiness may induce insulin resistance in rats via with decreasing amount and translocation of GLUT4 in adipocyte. Exercise training can raise the amount of plasma membranes GLUT4 protein in adipocyte of rats with insulin resistance, enhancing the ingestion and utilization of glucose.