Studying the mechanisms involved in the male sexual behavior by testosterone
Testosterone released during the perinatal period plays a crucial role in the permanente organization of the nervous system, potentiating typically male functions. In adulthood, testosterone activate these responses. In nervous system, testosterone can act either directly through androgen receptors (AR) or indirectly estrogen receptors (ERα and ERβ) after conversion into estradiol. We generated mice line selectively lacking AR or ERβ in the nervous system using the conditional mutagenesis approach. Thus we could study the relative involvement of AR and ERβ in the regulation of sexual behavior by testosterone. All male mice mutants conditional have a complete urogenital tract and are fertile. Our results indicate that, the regulation of sexual behavior by testosterone involves the AR and ERα. Indeed, we have shown that in brain, the AR is not required for the organization during development. But it is essential to activate sexual behavior in adulthood. However, at the spinal level, the AR plays an important role in both the organization and activation of the spinal bulbocavernosus nucleus. The ERβ seems to play a role either in the organization or in the activation of male sexual behavior by testosterone. We have assessed to what extent the exposure to low doses of bisphenol A (BPA) can interfere with the organizational and activationnal effects of testosterone. In fact, BPA is considered as an endocrine disruptor. We have shown that sexual differentiation of neural circuits is not affected by perinatal exposure. But, BPA could disrupt the activation of the androgenic signalling pathway of testosterone in adulthood, necessary for the expression of male sexual behavior.