Influence of endogenous prostaglandins on secretin-mediated inhibition of gastric acid secretion in dogs.

The influence of endogenous prostaglandins on secretin-mediated inhibition of gastric acid secretion was examined in 6 mongrel dogs with Thomas gastric and Herrera pancreatic cannulas. The dogs were given intravenous pentagastrin (1 microgram/kg.h) during the 180-min experiment, and graded doses of secretin (0.3-1.5 micrograms/kg.h) (1-5 CU/kg.h) were infused intravenously between 60 and 120 min. In alternate, otherwise identical experiments, a prostaglandin synthesis inhibitor, either indomethacin or meclofenamate, was also administered throughout the experiment. Increasing doses of secretin led to increasing inhibition of gastric acid output with the maximum inhibition at 1 microgram/kg.h (3.3 CU/kg.h) of secretin. Both indomethacin and meclofenamate abolished the inhibitory effects of secretin on gastric acid secretion. The inhibitors of prostaglandin generation had no effect on the serotonin system. We concluded that secretin mediates its inhibitory action on gastric acid secretion, at least in part, through endogenous prostaglandins.