Effects of 15(S)-15-methyl prostaglandin E2 methyl ester on phospholipid metabolism in rat gastric mucosa.

The effects of 15(S)-15-methyl prostaglandin E2 (PGE2) methyl ester on gastric mucosal metabolism of phospholipids in intact rats and rats injured by intragastric instillation of acidified taurocholic acid were examined by using radioisotope-labeled precursors. The incorporation of palmitic, oleic and arachidonic acids into phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was reduced by treatment with 15(S)-15-methyl PGE2 methyl ester in the intact rats, but the incorporation of glycerol was unaffected or affected only slightly. Instillation of acidified taurocholic acid resulted in decreased incorporation of palmitic acid and glycerol into PC and PE, whereas pretreatment with 15(S)-15-methyl PGE2 methyl ester caused the incorporations of these precursors to be maintained after acidified taurocholic acid treatment. These results suggest that 15(S)-15-methyl PGE2 methyl ester may reduce the incorporation of fatty acids into PC and PE by inhibition of the deacylation-reacylation cycle either directly or indirectly, whereas acidified taurocholic acid decreases de novo synthesis of PC and PE, and probably also the reacylation of fatty acid into phospholipids. Pretreatment with 15(S)-15-methyl PGE2 methyl ester protected the PC- and PE-synthesizing activity against the injury induced by acidified taurocholic acid, and this effect may be involved in the prevention of mucosal damage.