PHYSIOLOGICAL-ROLE OF CHOLECYSTOKININ ON GASTRIC-EMPTYING AND ACID OUTPUT IN DOGS

We investigated the physiological role of cholecystokinin (CCK) on gas tric emptying and acid secretion in seven conscious dogs with gastric cannulae. Two hundred milliliters of a 4% amino acid meal was given vi a the cannula, and both gastric emptying and acid output were measured concurrently using a dye-dilution technique. Gastric emptying of the liquid amino acid meal was exponential, and the acid output and plasma concentrations of CCK, gastrin, and somatostatin peaked within 30 min after the meal. Intravenous infusion of CCK-8 at 28 and 56 pmol/kg/hr but not 14 pmol/kg/hr increased plasma levels of the peptide and inhi bited gastric emptying as well as acid output. Plasma gastrin was not affected significantly by the CCK infusion, whereas plasma somatostati n increased significantly in response to 56 pmol/kg/hr of CCK-8. Loxig lumide, 22 mu mol/kg/hr, significantly enhanced gastric emptying and a ugmented acid output, as well as plasma gastrin response, whereas it a bolished the postprandial rise in plasma somatostatin. We concluded th at in dogs, CCK plays an important role in the physiologic regulation of postprandial gastric emptying of a liquid caloric meal and acid out put. Its inhibitory effect on gastric acid secretion appears to be med iated, at least in part, by somatostatin.