[Anti-ulcerogenic and cytoprotective effects of trimoprostil (Ro 21-6937), a trimethylprostaglandin E2 derivative].

Anti-ulcerogenic effects of trimoprostil, a prostaglandin E2 (PGE2) derivative, were studied in comparison with those of PGE2, cimetidine and sulpiride. Trimoprostil and PGE2 given p.o. prevented the formation of gastric lesions produced by absolute ethanol, 0.2N NaOH, 0.6N HCI and hypertonic NaCl solutions in rats and aspirin-induced fecal occult bleeding in dogs. Although both prostaglandins did not alter the gastric mucus content, they equivalently prevented the stress-induced decrease in the mucus content in rats. The duration of these effects of trimoprostil was longer than those of PGE2. Cimetidine and sulpiride did not exert such cytoprotective effects. Trimoprostil inhibited stress-induced gastric ulcer formation in rats more markedly than PGE2, cimetidine and sulpiride. Trimoprostil and PGE2 at the cytoprotective dose (30 micrograms/kg, p.o.) did not change the gastric blood flow in conscious rats. In Shay rats, trimoprostil at doses larger than the cytoprotective doses inhibited the gastric acid secretion when given p.o., but was not effective when given i.d. PGE2 exerted the similar action, but the potency was clearly weaker than that of trimoprostil. In Heidenhain-pouch dogs, trimoprostil also inhibited the gastric acid secretion stimulated by pentagastrin more markedly than did cimetidine. In conclusion, trimoprostil at doses smaller than the antisecretory doses exerted gastric cytoprotective action with a longer duration than that of PGE2, probably through the preservation of the mucus barrier. Such cytoprotection was not found with cimetidine and sulpiride.