Effect of ghrelin on gastric emptying, motilin and cholecystokinin levels in plasma in rats

Objective To investigate the effects of ghrelin on gastric emptying and expression of motilin and cholecystokinin (CCK) in plasma,and the action mechanism.Methods Sixty rats were randomly divided into six groups (intraperitoneal injection of ghrelin 0.5,1.0,1.5,2.0,2.5 nmol/kg,and control gorup),10 rats in each group.All rats were given intraperitoneal injection ghrelin,45 min later,they were given intragastric application of semisolid.They were killed after 30 min and gastric emptying was measured.Motilin and CCK levels in plasma in rats were assessed by using radioimmunoassay (RIA).Results After intraperitoneal injection of ghrelin,gastric emptying were significantly faster than controls [(38.24 ±7.15)％ vs.(27.18 ±2.37)％].Ghrelin accelerated gastric emptying in rats in a dose-dependent manner.Low dose of ghrelin could not acceleralte gastric emptying,but medium and high doses of ghrelin could accelerate gastric emptying.Meanwhiles,motilin and CCK levels were increased after intraperitoneal injection of ghrelin in rats.Conclusion Intraperitoneal injection of medium and high doses of ghrelin can acceleralte gastric emptying in rats,which might be regulated by motilin and CCK. Key words: Ghrelin;  Motilin ;  Cholecystokinin ;  Gastric emptying