Dexamethasone reduces the postcastration gonadotropin rise in women

To investigate the influence of glucocorticoids on gonadotropin release in humans, we studied the effects of dexamethasone (DXM) administration on basal and GnRH-stimulated gonadotropin secretion in normal women after bilateral ovariectomy (OVR). From the 7th to the 14th day after OVR, 9 women received DXM (2.25 mg/day) and 13 women received placebo (control women). Plasma FSH and LH concentrations were measured before OVR and daily from the 7th to the 14th day after surgery. In addition, the FSH and LH responses to exogenous GnRH (10 micrograms, iv bolus dose) were determined in all DXM-treated women and in 5 control women on the 7th and 14th days after surgery. Plasma gonadotropin levels increased similarly in all women on the 7th day after OVR. DXM administration significantly limited (P less than 0.001) the progressive rise of basal LH and FSH levels from days 7 to 14. DXM treatment also blunted (P less than 0.005) the OVR-induced increase in the responsiveness of both LH and FSH to exogenous GnRH. These findings suggest that glucocorticoids inhibit the secretion of both gonadotropins at the pituitary level in ovariectomized women.