THE ANTIREPRODUCTIVE ROLE OF CORTICOTROPIN-RELEASING HORMONE AND INTERLEUKIN-1 IN THE FEMALE RHESUS-MONKEY

Interleukin-1 alpha (IL-1 alpha) exerts numerous neuroendocrinological and immunological actions. In the ovariectomized (OVX) monkey, intracerebroventricular (icv) infusion of IL-1 alpha stimulates the hypothalamo-pituitary-adrenal (HPA) axis and inhibits pulsatile LH and FSH secretion. This inhibitory effect of IL-1 alpha on the gonadotropins is prevented by coadministration of corticotropin releasing hormone (CRN) and vasopressin (AVP) antagonists, suggesting a role of these two HPA neuropeptides. In order to understand the central mechanisms by which <<stress>> interrupts the menstrual cycle, we have also investigated the modulatory role of estradiol. When early follicular phase estradiol concentrations are reproduced, there was a complete prevention of HPA activation and of the consequent inhibition of gonadotropin by IL-1 alpha. The mechanisms regulating this unexpected action remain to be elucidated. In contrast, in the presence of late follicular phase estradiol concentr ations, the HPA response to IL-1 alpha is restored, but there is a stimulation of LH release. These data demonstrate interactions between the adrenal and gonadal endocrine axes, and highlight the role of estradiol in modulating these effects.