Acute and chronic stress-like levels of cortisol inhibit the oestradiol stimulus to induce sexual receptivity but have no effect on sexual attractivity or proceptivity in female sheep

Abstract

Stress-like levels of cortisol inhibit sexual receptivity in ewes but the mechanism of this action is not understood. One possibility is that cortisol interferes with the actions of oestradiol to induce sexual receptivity. We tested this hypothesis in 2 experiments with ovariectomised ewes that were artificially induced into oestrus by 12. days of i.m. injections of progesterone followed by an i.m. injection of oestradiol benzoate (ODB) 48. h later. In Experiment 1, ewes were randomly allocated to the following groups: saline infusion + 25 μg ODB, saline infusion + 50 μg ODB, cortisol infusion + 25 μg ODB or cortisol infusion + 50 μg ODB (n = 5 per group). Saline or cortisol was infused i.v...