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

Objective : To explore the effect of increase in Galanin release induced by exercise onInsulin sensitivity in the Rats and its possible mechanism.Method: the rats were divided into four groups: rest control group and exercises controlgroup were injected by saline through abdominal; rest drug group and exercises druggroup were injected by galantide, a galanin antagonist. The rats in both exercise controland exercise drug group swim in advance for three days, 15, 30, 50 minutes respectively;then swim officially for 10 days, 60 minutes every day. We investigated insulinsensitivity of the four group rats by the euglycemic clamp, measured the insulin plasmalevel in fasting rat by Radioimmunoassay and glucose plasma level by fast plasma glucoseinstrumental, measured the insulin sensitive indexes by divided the product of the plasmainsulin and the plasma glucose in fasting rat by 22.5 or calculated the natural logarithm ofthe product reciprocal, tested the level of glucose transportation protein 4 (Glut4) inskeletal muscle by Western blot method.Results: The insulin sensitivity in both exercise control and exercise drug groupsignificantly increases(P＜0.01). Galantide makes the insulin sensitivity remarkablydrop (P＜0.01), exercises may remarkably alleviate this drop (P＜0.05). Both plasmaglucose and plasma insulin levels of fasting rats in the rest drug group increase after theexperiment(P＜0.05). The plasma insulin level in the exercise drug group increasesafter the experiment also(P＜0.05). The insulin sensitive index in rest drug groupextremely remarkably drops after the experiment (P＜0.01). The skeletal muscleGLUT4 protein level in exercises control group increases by 26% compared to the restcontrol group (P＜0.01), while in the exercise drug group increases by 17.8% comparedto rest drug group (P＜0.05).Conclusion: The endogenous Gal is an essential important attribute to maintenance theinsulin sensitivity in whether rest or exercise conditions. Exercises may enhance theinsulin sensitivity by increasing the GLUT4 quantity and promoting transportation ofGLUT4 onto the cell membrane. However, Gal mainly promotes transportation ofGLUT4 onto the cell membrane or improves the activity of GLUT4 to increase theinsulin sensitivity, but not increases the GLUT4 quantity.