Role of secretin on postprandial gastrin release in the dog: a further study.

To determine the physiologic role of secretin on gastric secretory function, the effects of secretin in a physiologic dose on gastrin release and gastric acid secretion were studied in four dogs with vagally innervated fundic pouches. Three sets of experiments were performed in each dog: (1) meal alone, (2) meal after intravenous cimetidine to suppress acid secretion and release of secretin, and (3) meal after intravenous cimetidine with simultaneous intravenous secretin, 0.03 clinical unit (CU)/kg-hr. A significant increase in plasma secretin concentration occurred after ingestion of a meal. The postprandial increase in the secretin level was abolished by intravenous cimetidine 200 mg, whereas intravenous cimetidine resulted in a marked increase in the postprandial plasma gastrin concentration which was significantly greater than that after a meal alone. A plasma secretin level comparable to that of the postprandial period could be achieved in the same fasting dogs by intravenous secretin, 0.03 U/kg-hr in 2% dog albumin solution. The postprandial plasma gastrin concentration and acid secretion following intravenous cimetidine were significantly decreased by simultaneous intravenous secretin at a dose of 0.03 U/kg-hr. The observations indicate that secretin plays a significant role in the regulation of release of gastrin and gastric secretion of acid in the postprandial state in dogs.