Anti-estrogen inhibition of androgen induced sexual receptivity in rats

Abstract

It has been known for some time that the administration of testosterone propionate or testosterone propionate plus progesterone can induce lordosis behavior in female rats much as can estrogen treatment. It has been suggested that this phenomenon reflects an androgen to estrogen metabolism of the administered testosterone. In the present study it was argued that if this hypothesis were true it should be possible to block androgen induced lordosis with an anti-estrogen which is known to block estrogen induced lordosis. Ovariectomized female rats were administered either testosterone propionate plus progesterone or testosterone propionate plus anti-estrogen plus progesterone. Androgen treatment led to the display of lordosis; anti-estrogen blocked androgen induced lordosis. The anti-estrogen used was CI-628 (CN 55,945-27, Parke, Davis). When this anti-estrogen was administered to male rats it failed to block androgen maintained seminal vesicle weight, or normal male mating patterns suggesting that this agent does not possess anti-androgenic properties. The data are consistent with the hypothesis that androgen induces female lordosis patterns by first being converted to estrogen.