Effects of minipuberty disruption on the expression of sexual behavior in female mice.

Sex steroids influence early organization of neural structures involved in expression of sexual behavior. A critical perinatal period during which testosterone surges occur has been identified in male rodents. Data are lacking for females, whose ovarian activity starts later in the postnatal period. Minipuberty has been described in female as a first postnatal period of gonadotropic axis activation. We transiently disrupted the minipubertal period, using daily injections of GnRH antagonist or aromatase inhibitor. The results showed unchanged puberty initiation and mild disturbance of estrus cyclicity. Minor modifications of some components of sexual behavior (olfactory preference, ability to attract male) were observed, but had no impact on lordosis behavior. Interestingly, letrozole-treated female mice showed increased anxiety state level at adulthood. This period therefore does not seem to be a key organizational window for female sexual behavior but appears to participate in the organization of neural structures involved in anxiety-related behavior.