Effects of various gastrointestinal peptides on gastric somatostatin release

Effects of various gastrointestinal peptides on gastric somatostatin release from the isolated perfused rat stomach were studied. After isolation of the stomach in a fasted rat by the method of Lefébvre and preperfusion with 4.6% dextran-Krebs-Ringer bicarbonate buffer containing 5.5 mM glucose, each peptide was infused into the left gastric artery at a constant rate for 15 min. Secretin and bombesin caused a significant increase of gastric somatostatin release in a dose-related manner (10(-8)-10(-6) M). Gastric somatostatin release was also stimulated after the administration of pentagastrin (10(-8)-10(-6) M). In contrast, both methionine-enkephalin and substance P decreased gastric somatostatin release in a dose-related manner (10(-8)-10(-6) M), whereas neurotensin (10(-8)-10(-6) M) failed to change it significantly. The present results suggest that these various gastrointestinal peptides may regulate gastric somatostatin secretion.