Involvement of Cholecystokinin (CCK) Receptor in the Adaptation of Gastric Emptying Induced by Adrenocorticotropin (ACTH) in Male Rats

Abstract

It has been shown that gastric emptying is delayed in stressed animals. This investigation was to study the effect of adrenocorticotropin (ACTH), a stress hormone, on the gastric emptying and intestinal transit in rats. Fasted male rats were injected intraperitoneally (i.p.) with saline, ACTH (10 or 20 μg/ml/kg), lorglumide (a selective potent cholecystokinin A receptor antagonist, 10 μg/ml/ kg) or ACTH (20 μg/ml/kg) and lorglumide (10 μg/ml/kg) at 30 min before decapitation. All rats were orally ingested with liquid meal containing radioactive Na_2 ^(51)CrO_4 (0.5 μCi/ml) and 10% charcoal at 15 min before decapitation, and blood samples were collected. Administration of ACTH significantly increased the concentrations of plasma corticosterone, but decreased the levels of plasma cholecystokinin (CCK) and gastric emptying as well as intestinal transit in rats. The decreased gastric emptying, but not intestinal transit, was reversed by the treatment of lorglumide. These results suggested that CCKA receptor was involved in the inhibitory effect of ACTH on the gastric emptying in rats.