Abstract
Bombesin has both direct and indirect effects on pancreatic exocrine secretion in mammals. The latter is mediated through the release of cholecystokinin (CCK) . In rats, however, it is unclear whether bombesin's effects are direct or are mediated via release of CCK. This study was undertaken to determine the role of CCK in bombesin-stimulated pancreatic enzyme secretion in conscious rats. Pancreatic flow and protein output were increased significantly, two to three-fold over the basal secretion at 30 minutes after administration of 0.25 μg/kg/h and 0.5 μg/kg/h of bombesin in rats. Plasma CCK levels were not changed during that period in which pancreatic secretion was stimulated by bombesin. CR 1505, a CCK receptor antagonist, at 50 mg/kg, did not suppress pancreatic exocrine secretion stimulated by bombesin. It is concluded that the effect of bombesin on pancreatic secretion is a direct effect, and not mediated via release of CCK in rats.
