Effects of branched chain fatty acids of iso-C12:0 to iso-C16:0 on gastric secretion and experimental ulceration in rats.

We examined the inhibitory activities of branched-chain fatty acids of iso-C12:0 to iso-C16:0 on gastric secretion in rats. Consequently, iso-C13:0 and iso-C15:0 were found to have strong inhibitory activities on gastric secretion in rats. In the case of intraduodenal administration, iso-C15:0 also showed a significant inhibition of gastric juice secretion. Therefore, the effects of iso-C13:0 and iso-C15:0 on ulceration in pylorus-ligated rats and aspirin-induced ulcer were examined. At the doses of 10 and 25 mg/kg, iso-C13:0 and iso-C15:0 significantly decreased the ulcer index in pylorus-ligated rats, and aspirin-induced ulcer was also significantly inhibited at the doses of 25 and 50 mg/kg. Finally, effect of iso-C15:0 on pepsin, Mg++-ATPase and carbonic anhydrase, which are considered to play an important role in the mechanism of gastric juice secretion, was examined in vitro, centering around iso-C15:0 which showed a marked effect in gastric juice secretion inhibitory and anti-ulcerogenic activities. Iso-C15:0 showed inhibitory activity on pepsin and Mg++-ATPase, but entirely no activity on inhibiting carbonic anhydrase.