Objective: 

Ghrelin, an orexigenic peptide produced in the stomach is increased in streptozotocin (STZ)-induced diabetic rats. In rodents, intracerebroventricular or peripheral administration of ghrelin stimulated food intake and body weight gain. This study clarifies the regulation of ghrelin by insulin in STZ- induced diabetic rats.

Methods: 

Adult male Wistar rats were divided into control and three experimental groups as each group had 7 rats (n=28). To investigate the role of ghrelin in the hyperphagic response to uncontrolled diabetes, rats in each group were studied for 7 days. Rats were injected once daily for 7 days with either PBS or insulin subcutaneous injection (5-7 U). Body weight and food intake were measured before and after the experimental procedure. Plasma insulin, ghrelin and glucose concentrations were also measured.

Results: 

Streptozotocin (STZ)-induced diabetic rats were markedly hyperphagic. This hyperphagia was accompanied by hyperglycemia and hypoinsulinemia. Treatment of diabetic rats with insulin reversed these changes. STZ- diabetic rats had higher plasma ghrelin concentrations than control rats. Changes in ghrelin levels were attenuated by the subcutaneous injection of insulin (5–7 U over 7 days). Insulin treatment also partially reversed hyperphagia observed in STZ- induced diabetic rats and there was a decrease in plasma ghrelin concentrations compared with STZ-INS pair fed rat.

Conclusions: 

The results indicate that insulin treatment reverses elevated plasma ghrelin concentrations in STZ- induced diabetic rats. So this shows the pathophysiological significance of ghrelin in diabetes.