The Effect Of Increase Of Galanin Induced By Exercise On Insulin Sensitivity In Type 2 Diabetic Rats

Objective : In order to explore the effect of increase in Galanin release induced by exercise on Insulin sensitivity in the type 2 diabetic rats and its possible mechanism. Method :Female Sprague-Dawley rats were used to this experiment After high-fat diet for 8 weeks.Rats were subjected to establish 2 type diabetic model by injection of streptozotocin. (30mg/kg). When the models of diabetic rats were formed,Diabetic rats were randomly divided into four groups: rest control group and exercise control group were injected by saline into the abdominal cavity; rest drug and exercise drug groups by galantide,a galanin antagonist. The rats of both exercise groups swam in advance for three days, 15, 30, 50 minutes respectively; then swam formally for 10d, 60 min/d; We investigated insulin sensitivity of the four group rats by the euglycemic clamp, measured the insulin plasma level in fasting rat by Radioimmunoassay and glucose plasma level by fast plasma glucose instrumental,measured the insulin sensitive indexes by divided the product of the plasma insulin and the plasma glucose in fasting rat by 22.5 or calculated the natural logarithm of the product reciprocal,tested the glucose transportation protein 4(GLUT4) level in skeletal muscle by Western blot method.Results: The results showed that the glucose infusing speed in exercise control group and exercise drug group increase significantly(P<0.05) in the euglycemic clamp test,while in both drug groups significantly drop(P<0.05) vs respective control groups. Both plasma glucose and plasma insulin levels of fasting rats in the rest drug group increase after the experiment(P<0.05). The plasma insulin level in the exercise drug group also increases after the experiment (P<0.05). The insulin sensitive index in rest drug group extremely remarkably drops after the experiment (P<0.01). The skeletal muscle GLUT4 protein level in exercises control group extremely remarkably increases compared to the rest control group (P<0.01), while in the exercise drug group increases significantly compared to rest drug group (P<0.05). while in both drug groups significantly drop(P<0.05) vs respective control groups. The skeletal muscle GLUT4 protein level has no significant significance.Conclusion: These results suggest that the endogenous galanin is an essential important attribute to maintenance the insulin sensitivity in both of rest and exercise conditions. Exercise may enhance the insulin sensitivity by both ways,including increasing the GLUT4 quantity and promoting the GLUT4 transportation onto the cell membrane. However, galanin may be mainly through increasing the GLUT4 transportation onto the cell membrane or improving the activity of GLUT4.