[Effects of exercise on expression and phosphorylation of PI3K and PKB in insulin signaling in the skeletal muscles of type 2 diabetic rats].
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Cao
Shi-cheng
SC
Department of Sports Medicine, College of Basic Medical Sciences, China Medical University, Shenyang 110001, China. caoshicheng@tom.com
Zhao
Gang
G
Chang
Bo
B
Zhang
He
H
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010805:Physical Conditioning, Animal; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
D051275:Glucose Transporter Type 4; D007328:Insulin; C495694:Slc2a4 protein, rat; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt