Although galanin has been shown to increase GLUT4 expression in the cardiac muscle of rats, there is no literature available about the effect of GalR1 on GLUT4 expression in the cardiac muscle of type 2 diabetic rats. The aim of this study was to determine whether intracerebroventricular injection of GalR1 agonist M617 would elevate GLUT4 expression in the cardiac muscle of type 2 diabetic rats. The rats tested were divided into four groups: rats from healthy and type 2 diabetic drug groups were injected with 10nM/kg/d M617 in 5μl artificial cerebrospinal fluid for 21days, while control received 5μl vehicle injections. The blood samples were analyzed for glucose and insulin concentration. Cardiac muscle was collected and processed for determination of GLUT4 mRNA expression and GLUT4 protein levels. The present findings showed that fasting blood glucose levels in both M617 treatment groups were lower compared with each control. The insulin levels in both M617 treatment groups were decreased compared with each control. Moreover, the GLUT4 content in the cardiac muscle in both drug groups was higher compared with each control. M617 treatment increased GLUT4 mRNA expression and GLUT4 protein levels compared with each control group. These observations suggest that GalR1 agonist M617, acting through its central GalR1, can promote GLUT4 expression and enhance GLUT4 content in the cardiac muscle of type 2 diabetic rats. Central GalR1 may play a significant role in regulation of glucose metabolic homeostasis in the cardiac muscle of type 2 diabetic rats.
Keywords: Cardiac muscle; GLUT4; Galanin; M617.
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