Effects of exercise on expression and phosphorylation of PI3K and PKB in insulin signaling in the skeletal muscles of type 2 diabetic rats / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effect of exercise on the expressions of phosphatidylinositol 3 kinase (PI3K) and protein kinase B (PKB) phosphorylation, protein and glucose transport proteins (GLUT4) at both the protein and mRNA levels in the skeletal muscles of type 2 diabetic rats.</p><p><b>METHODS</b>Thirty male SD rats were randomly divided into control group with normal diet feeding, diabetic group and diabetic exercise group with high-fat diet feeding. After 8 weeks of the high-fat diet, each rat received an intraperitoneal injection of streptozotocin (STZ, 30 mg/kg). Three weeks after the injection, the rats were rated for the presence of diabetes, and the rats in the exercise groups took swimming training for 4 weeks; all the groups maintained their assigned diets. The gastrocnemius of all the rats were dissected 48 h after the last training session. Western blotting was applied to detect the phosphorylation and protein expression of PI3K and PKB and the protein expression of GLUT4. The expression of GLUT4 mRNA was determined by RT-PCR.</p><p><b>RESULTS</b>Compared with the diabetic group, the diabetic rats in the exercise group showed significantly increased protein expression and phosphorylation of PKB (P<0.05) and elevated GLUT4 protein and mRNA expressions in the skeletal muscles (P<0.01, P<0.05).</p><p><b>CONCLUSION</b>Exercise training can modulates insulin signal transduction through the protein expression and phosphorylation of the protein kinase to promote glucose uptake in the skeletal muscle of type 2 diabetic rats.</p>