ANTI-ULCER ACTIVITY OF HYPERTONIC SOLUTIONS IN THE RAT - POSSIBLE ROLE OF PROSTAGLANDINS

The effects of hypertonic solutions on gastric acidity and on experimental gastric and duodenal ulcers and on gastric prostaglandins (PG) were studied in the rat. The oral administration of a 10% NaCl solution caused complete absence of free acidity and very significant reductions in total acidity 24 h after pyloric ligation. The antiulcer effect of hypertonic saline was studied in 3 experimental models. In pyloric-ligated rats, both the incidence and the severity of gastric ulcers were remarkably reduced by hypertonic saline treatment. Indomethacin-induced gastric erosions were significantly reduced by hypertonic NaCl or sorbitol and completely prevented by hypertonic xylitol. Cysteamine-induced duodenal ulcers were significantly reduced by hypertonic solutions of NaCl, xylitol or sorbitol. In the later model, indomethacin potentiated the ulcerogenic effect of cysteamine and reduced the efficacy of the hypertonic NaCl gavage. The possible contribution of PG to these effects was studied by analyzing PGE in the gastric mucosa and juice. Rats treated orally with hypertonic NaCl solutions had several-fold higher PGE contents in their gastric mucosa and higher PGE levels in the gastric juice. Hypertonic solutions may stimulate endogenous PGE biosynthesis and exert profound antiulcer effects in the rat. A causal relationship between the 2 phenomena is suggested.