Abstract: To investigate the effects of insulin, metformin and pioglitazone on plasma ghrelin and the expression level of ghrelin in stomach tissues of type 2 diabetic rats and to explore the correlation between ghrelin and insulin sensitivity. MethodsType 2 diabetic rat model was established by feeding with high glucose and high fat diets and injecting a low dosage of streptozotocin(STZ). Then the diabetic rats were divided into four groups: the diabetic control group(DC), the insulintreatment group(INS), the metformintreatment group(MET) and the pioglitazonetreatment group(PIO). 8 weeks later, the plasma ghrelin and the ghrelin expression levels in the stomach were determined by enzymelinked immunoassay(EIA) and immunohistochemistry. ResultsThe ghrelin levels of the plasma and stomach were increased in the INS group compared with the DC group, but the difference was not significant. The ghrelin levels of the plasma and stomach in the MET and PIO groups were significantly increased compared with the DC group(P＜0.01). The plasma ghrelin level was negatively correlated with FINS, but positively with ISI in the DC, MET and PIO groups. Multiple linear regression analysis showed that FINS and ISI were independent factors for the plasma ghrelin level. Conclusion Metformin and pioglitazone can increase the ghrelin levels of the plasma and stomach tissues and the insulin sensitivity in type 2 diabetic rats.

Key words: Diabetes mellitus, Type 2, Ghrelin, Insulin sensitivity, Rats, Wistar