Modulation of rat gastric mucosal prostaglandin E₂ release by dietary linoleic acid: Effects on gastric acid secretion and stress-induced mucosal damage

We studied chronic intake of diets deficient in or supplemented with linoleic acid to determine whether it affects gastric acid secretion, release of prostaglandin E₂, and stress-induced lesions. For 8-10 wk rats were fed three dietary regimens supplying 3.5% (control group), 0.3%, and 10% of total calories as linoleic acid. We found that diets deficient in linoleic acid (0.3%) reduced release of prostaglandin E₂ into the gastric lumen (-77%) and increased basal (+133%) and pentagastrin-stimulated acid secretion (+93%) and the area of cold restraint-induced gastric mucosal lesions (+280%), when compared with the control group. Diets supplemented with linoleic acid (10%) increased prostaglandin E₂ release into the gastric lumen (+106%) and reduced basal (-44%) and pentagastrin-stimulated acid secretion (-78%) and the area of cold restraint-induced mucosal lesions (-80%). Prevention of these lesions by the 10% linoleic acid diet was confirmed by quantitative histology. Pretreatment with indomethacin (8 mg/kg intraperitoneally) abolished the effects of the 10% linoleic acid diet on prostaglandin formation, acid secretion, and mucosal injury. We conclude that in rats chronic intake of dietary linoleic acid reduces acid secretion and prevents cold restraint-induced mucosal lesions, possibly because of augmented synthesis of endogenous prostaglandins in the gastric mucosa.