Pituitary responses to synthetic corticotropin-releasing hormone: absence of modulatory effects by estrogen and progestin.

To determine if the activity of the adrenocorticotropic hormonal-adrenal axis is modulated in part by estrogens and progestins, we have compared pituitary and adrenal responses to corticotrophin-releasing hormone in normal women during the early follicular, late follicular, and midluteal phases of the menstrual cycle and in four women undergoing ovariectomy who received estradiol (E2) implants alone or in combination with oral medroxyprogesterone acetate administration. Basal adrenocorticotropic hormone and cortisol levels (9:00 AM) and responses to ovine CRH were unaffected by variations in E2 and progesterone during each phase of the menstrual cycle. In women undergoing ovariectomy who received E2 replacement therapy, basal concentrations of adrenocorticotropic hormone and cortisol (9:00 AM) and the responses to human corticotrophin-releasing hormone were not altered by administration of E2 alone or E2 with medroxyprogesterone acetate. Under these experimental conditions, our findings suggest that physiologic changes in E2 and progesterone levels during the menstrual cycle and replacement doses of estrogen and progestin commonly used clinically do not significantly influence basal adrenocorticotropic hormone and cortisol levels or responsiveness to corticotrophin-releasing hormone.