Abstract: Objective: To investigate the effect of recombinant leptin on plasma ghrelin levels and the expression of ghrelin mRNA in the stomach of streptozotocin(STZ)-induced diabetic rats. Methods: Wistar rats were divided into four groups: the control group, the diabetes group(the DM group), the DM leptin group(the DM-LEP group) and the DM-LEP pair-fed group(the DMPF group). DM-LEP rats were subjected to leptin at a dosage of 4?mg/kg sc daily for 7 days. The body weight, blood glucose, insulin, leptin and ghrelin were determined. Furthermore, leptin mRNA expression in the adipose tissues and ghrelin mRNA expression in the stomach were determined. Results: Food intake in the DM-LEP group significantly decreased compared with the DM group (P＜0.05). The plasma glucose significantly decreased in the DMLEP group compared with the DM and the DM-PF groups (P＜0.05). The serum leptin and leptin mRNA expressions in adipose tissues were lower in the DM-LEP group than those in the DM group(P＜0.05),　but were significantly higher than those in the control group. The plasma ghrelin and ghrelin mRNA expressions in the stomach were also markedly decreased in the DM-LEP group compared with the DM group. Conclusion: Leptin can reverse elevated plasma ghrelin levels and ghrelin mRNA expression in the stomach independent of the fasting insulin concentration and food intake.

Key words: Diabetes mellitus, Streptozotocin, Leptin, Ghrelin