Effects of peptides on gastric emptying.

The effects of peptides on gastric emptying of a liquid meal were studied in rats. Gastric emptying was found to be delayed following intraperitoneal injection of the octapeptide of cholecystokinin (CCK-8). Vasoactive intestinal peptide did not effect emptying, while substance P and neurotensin caused a moderate acceleration in gastric emptying. After oral administration of a solution containing the amino acids tryptophan and phenylalanine, but not glycine, a statistically significant inhibition of gastric emptying was observed. Our results suggest an involvement of CCK in the regulation of gastric emptying.