EFFECT OF DEXAMETHASONE ON LUTEINIZING-HORMONE AND FOLLICLE-STIMULATING HORMONE RESPONSES TO LHRH AND TO CLOMIPHENE IN THE FOLLICULAR PHASE OF WOMEN WITH NORMAL MENSTRUAL CYCLES

In an attempt to elucidate the mechanism of suppressive action of glucocorticoids on the hypothalamo-pituitary-ovarian axis, we studied the effects of short-term high dose dexamethasone administration on the LH and FSH responses to LHRH and to clomiphene in healthy women with normal menstrual cycles. Seven women, 21-35 years of age, received 100 μg of LHRH i.v. on day 6 of two consecutive menstrual cycles, once with and once without pre-treatment with dexamethasone 2 mg orally every 6 hrs. on days 2 through 5 of the menstrual cycle. Seven other women (ages 21-35 years) received clomiphene citrate 100 mg on days 2 through 5 of their menstrual cycle, once with and once without simultaneous administration of dexamethasone 2 mg orally every 6 hr. The administration of dexamethasone suppressed baseline serum levels of LH and FSH and blunted LH and FSH responses to both LHRH and clomiphene. The results indicate that short-term administration of pharmacological doses of glucocorticoids suppress the secretion of LH and FSH by a direct effect on the anterior pituitary and possibly by an effect at the hypothalamic level with inhibition of the release of LHRH.