EFFECTS OF 15(R)-15-METHYL PROSTAGLANDIN-E2 (ARBAPROSTIL) ON GASTRIC-SECRETION AND VARIOUS GASTRIC-LESIONS INDUCED IN RATS

We studied the effects of 15(R)-15-methyl prostaglandin E2 (arbaprostil) on gastric secretion and various acute and chronic gastric lesions produced in rats. Arbaprostil significantly inhibited gastric secretion in 4 hr-pylorus-ligated preparations when given intraduodenally in a dose of 30 or 100 .mu.g/kg. The agent, however, significantly stimulated gastric secretion of rats with either a ligated or intact pylorus when given orally in doses of 3-100 .mu.g/kg. Orally administered arbaprostil dose-dependently prevented the development of HCl-ethanol-histamine-, water-immersion stress-, or indomethacin-induced gastric erosions. Intraduodenally administered arbaprostil also dose-dependently prevented the development of aspirin-induced gastric erosions in pylorus-ligated rats. Arbaprostil, given orally in doses of 1-100 .mu.g/kg twice daily for 2 weeks, had little or no effect on the healing of acetic acid-induced gastric ulcers. However, oral administration of the agent in a dose of 3 or 10 .mu.g/kg twice daily for 4 weeks significantly accelerated the healing of acetic acid-induced gastric ulcers. The increase in doses up to 100 .mu.g/kg twice daily for 4 weeks had no effect on ulcer healing. These results indicate that arbaprostil, at either antisecretory or even acid stimulating doses, is effective in preventing the development of acute gastric erosions and in accelerating the healing of chronic gastric ulcers.