Stressor specificity of sex differences in hypothalamo-pituitary-adrenal axis activity: Cortisol responses to exercise, endotoxin, wetting, and isolation/restraint stress in gonadectomized male and female sheep

Abstract

Sex differences in the stress-induced activity of the hypothalamo- pituitary-adrenal axis in sheep appear to be dependent on the stressor encountered and occur irrespective of the presence of gonadal steroids. Wetested the hypotheses that cortisol responses to exercise, endotoxin, wetting (experiment 1), and isolation/restraint (experiment 2) stress differ between gonadectomized male and female sheep. At weekly intervals (in experiment 1), we subjected gonadectomized rams and ewes (n = 6/group) to control conditions, to exercise stress, to iv injection of endotoxin, and to wetting stress. In a second experiment (experiment 2), we subjected gonadectomized rams and ewes (n = 5/group) to contro..