Effect of trimoprostil on gastric secretion in man

The effect of trimoprostil, an analogue of prostaglandin E2, on gastric secretion was studied in healthy volunteers in comparison with that of cimetidine. Graded doses of 50, 250, 500 and 750 micrograms were given p.o. for trimoprostil and 200 mg for cimetidine. Basal secretion was significantly depressed at doses larger than 500 micrograms of trimoprostil but not by 200 mg of cimetidine probably due to the method of gastric analysis adopted in the study. In amyl-oxy-carbonyl (AOC)-tetragastrin stimulated gastric secretion, 500 micrograms of trimoprostil depressed acid output significantly, but did not affect pepsin output which was depressed, however, at 750 micrograms. On the other hand cimetidine markedly inhibited AOC-tetragastrin stimulated acid and pepsin secretion. Some difference was also recognized between trimoprostil and cimetidine concerning the mechanism of inhibitory action. Serum concentration of trimoprostil measured at 60 min after oral administration varied dose-dependently and antisecretory effects were also found to be dose-related. Serum gastrin and pepsinogen I were not affected either by trimoprostil or cimetidine. These results indicate that trimoprostil showed inhibitory effect on gastric secretion at doses larger than 500 micrograms for acid, and at doses larger than 750 micrograms for pepsin.