Arachidonic acid protection of rat gastric mucosa against ethanol injury.
AA, an essential dietary fatty acid, is a precursor for synthesis of prostaglandins. The ability of prostaglandins to protect the gastric mucosa against ethanol injury prompted us to investigate the possibility of AA providing similar protection in the rat. AA or its solubilizer were instilled intragastrically 60 min prior to absolute ethanol. The gastric lining was examined at 3 and 15 hr after the administration of ethanol. The extent of damage was assessed both macroscopically and histologically. AA administration 30 or 60 min prior to ethanol ingestion protected the gastric mucosa against macroscopic and histological damage for 3 to 15 hr. The intragastric concentration of prostaglandin E2 was 5,000 to 13,000 times higher in the animals pretreated with AA than in the controls. The protective action of AA was markedly diminished by indomethacin pretreatment. Intrajejunal administration of AA did not protect the gastric mucosa. These experiments demonstrate that a dietary constitutent--arachidonic acid--can protect the gastric mucosa against alcohol injury by inducing the synthesis of prostaglandins by the gastric mucosa.