ROLE OF GASTRIC-MUCOSAL PROSTAGLANDIN-E(2) IN THE INHIBITORY-ACTION OF SECRETIN AND SOMATOSTATIN ON GASTRIC-ACID SECRETION IN THE RAT

We investigated the effect of indomethacin on secretin- and somatostat in-induced inhibition of gastric acid secretion stimulated by intraven ous infusion of pentagastrin (0.3 mug/kg.h) in anesthetized rats. Intr avenous administration of a prostaglandin synthesis inhibitor, indomet hacin (2 mg/kg + 1 mg/kg.h), completely abolished the inhibition of ga stric acid secretion induced by intravenous infusion of secretin (0.05 CU/kg.h). The inhibitory effect of intravenous infusion of somatostat in (Sandostatin; 0.2 mug/kg.h) on the gastric acid was not significant ly changed by indomethacin. Secretin significantly increased the gastr ic mucosal content of prostaglandin E2, and the increase was completel y blocked by indomethacin. Somatostatin, however, had no significant e ffect on gastric mucosal prostaglandin E2. The results suggest that en dogenous prostaglandin is involved in the mechanism of inhibition of g astric acid secretion by secretin, but not by somatostatin.