Effect of 16,16-dimethyl prostaglandin E2 on ethanol-induced damage to canine oxyntic mucosa

Previous reports have demonstrated that the synthetic prostaglandin analogue, 16,16-dimethyl prostaglandin E 2 (dm PGE 2 ), protects the rat gastric mucosa against the damaging effects of a variety of ulcerogenic agents, including alcohol. The effects of dm PGE 2 on alcohol-induced gastric mucosal injury in the dog has not been investigated. Using the canine Heidenhain pouch, the present study examined the action of dm PGE 2 on gastric mucosal damage induced by 15% ethanol, both in the presence and absence of HCl. Ethanol by itself damaged the pouches as evidenced by large net fluxes of Na + and K + into the pouch. The combination of ethanol and 100 mn HCl produced the same effects on Na + and K + and also increased pepsin secretion into the pouch and the loss of H + from the bathing solution. Intravenous injection of dm PGE 2 in the doses 0.01, 0.1, and 1.0 μg per kg, one-half hour before administration of ethanol in acid solution, significantly reduced the net loss of H + from the pouch and the gain of Na + , K + , and pepsin. The most effective doses for protection were 0.1 and 1.0 μg per kg. The increases in Na + and K + efflux elicited by ethanol in the absence of HCl were also significantly reduced by dm PGE 2 . It is concluded that dm PGE 2 effectively protects the canine gastric mucosa against the damaging effects of alcohol and that this protection is dose-related. Although the mechanism underlying this protection is not apparent from this study, it appears to be independent of inhibition of acid secretion because equal protection against ethanol was observed both in the presence and absence of HCl.