Role of androgens in the regulation of sexual behavior in the female musk shrew.

These experiments were conducted to determine whether androgens are involved in the regulation of female sexual behavior in the musk shrew (Suncus murinus). In the musk shrew, sexual behavior can be reinstated after ovariectomy by the administration of supraphysiological doses of either estradiol (E2) or testosterone. However, physiological doses of E2 are not effective in this regard. To examine the role of androgens, ovariectomized (OVX) females received testosterone-filled hormone implants. These implants reinstated sexual behavior in a dose-dependent manner. To determine whether the aromatization of androgen is essential for restoration of sexual behavior, the nonaromatizable androgen, dihydrotestosterone (DHT), was administered to OVX females either alone or with an implant containing E2; sexual behavior was not restored. In the third experiment, gonadally intact females, treated with the aromatization inhibitor 1,4,6-androstatriene-3,17-dione (ATD) exhibited no sexual behavior and had significantly lower levels of aromatase activity in the medial basal hypothalamus/preoptic area than control females. In the last experiment, OVX females implanted with testosterone and given concurrent ATD treatment demonstrated significantly less sexual behavior as compared with controls. These results suggest that either estrogens produced via androgen aromatization in the brain and/or an intermediate product in the aromatization process are involved in the regulation of sexual behavior in the female musk shrew.