EFFECTS OF STRESS ON GASTRIC-MUCOSAL PROSTAGLANDIN GENERATION IN INTACT, ADRENALECTOMIZED, AND SHAM-OPERATED RATS

To study the effects of (a) cold restraint stress and (b) adrenalectomy in association with cold restraint stress on gastric mucosal ulceration and prostaglandin generation, we performed two experiments. In the first, 40 rats were divided into four groups of 10 rats each: (a) unstressed and (b) stressed for 0.5 h, (c) stressed for 2 h, and (d) stressed for 4 h. In the second experiment, another 80 rats were divided into four groups of 20 rats each: (a) adrenalectomy plus cold restraint stress for 2 h, (b) adrenalectomy plus no stress, (c) sham operated plus 2 h of stress, and (d) sham operated plus no stress. In both experiments we recorded an ulcer index and measured mucosal generation of prostaglandin E2 (PGE2) and prostaglandin I2 (6-keto-PGF1a). In conclusion: (a) Cold restraint stress is associated with a time-dependent decrease in gastric mucosal PGE2 generation, but no change in 6-keto-PGF1a generation, and an increase in mucosal injury that is maximal by 2h. (b) Adrenalectomy augments the effects of stress on mucosal injury but has no effect on prostaglandin generation; thus, the ulcerogenic effect of adrenalectomy appears to be independent of an effect on prostaglandin generation. © 1990 Raven Press, Ltd., New York.