Sex differences and gonadal hormones influence susceptibility to the activity-stress paradigm.

The present study investigated the effect of gonadal hormones on activity, food consumption, severity of ulceration, weight loss, and survival duration in male and female rats exposed to the activity-stress (A-S) paradigm. Animals received either sham surgery or gonadectomy and were housed in activity wheels or standard suspended cages. Results indicated that gonadectomized animals were more likely to engage in high running levels in the A-S paradigm; in addition, castrated males developed significantly more ulceration than the other groups. Neither sex nor gonadectomy affected the survival duration of A-S animals.