Effects of adrenalectomy on the stress-induced changes in ovarian sympathetic tone in the rat

Abstract

A 3-wk period of stress promotes the development of ovarian cysts in rats apparently mediated by increased sympathetic nerve activity and ovarian steroid secretion. After 11 wk of stress, these parameters are indistinguishable from nonstressed control rats. To study adrenal contribution, we adrenalectomized rats and studied the effect of 3-wk of cold/restraint stress (1.5 h/d) on them compared to intact animals. Adrenalectomy (ADX) increased ovarian norepinephrine (NE) release, the content of beta-adrenergic receptors (BAR) and basal, but not isoproterenol (Iso)-induced, androgen secretion. Stress to intact animals increased NE release, decreased beta AR content, and Iso-induced, but not basal, androgen secretion from the ovary. ADX did not modify the response to stress. We propose a tonic inhibition by the adrenal gland on nerve activity of ovarian nerves. Stress overrides this inhibitory effect, and nerve activity downregulates beta AR, decreasing ovarian steroid secretion.