Danazol Suppression of Luteinizing Hormone in the Rat: Evidence for Mediation by both Androgen and Estrogen Receptors

Previous studies had indicated that the effects of danazol on rat peripheral tissues were mediated through both androgen and estrogen receptors. The purpose of this study was to examine the role of androgen and estrogen receptors in danazol suppression of luteinizing hormone (LH) in the rat. The estrogen receptor antagonist, LY 156758, partially antagonized the suppressed levels of LH observed 3-5 hr after administration of danazol to ovariectomized rats. In contrast, the androgen receptor antagonist, flutamide, had no effect on suppressed LH levels 3-5 hr after danazol, but did partially reverse the inhibition of LH 24 hr after danazol administration to ovariectomized rats. Danazol also increased pituitary progesterone receptor levels, an estrogen-sensitive end point. These data indicate that the suppressed levels of LH following danazol treatment resulted from the functional activation of both androgen and estrogen receptors.