[Influence of neonatally administered gonadotropin on the sexual function of adult rats].

Male and female rats were daily injected with 10 IU HCG plus 10 IU FSH from the 1st to 14th day of life in order to investigate the influence of neonatal gonadotrophin administration on the sex-specific differentiation of the brain. When adult, the males showed hypogonadism associated with approximately normal sexual activity. In the females, precocious puberty, indicated by premature vaginal opening and spontaneous estrus, occurred. Furthermore, bisexuality with a tendency towards more male behavioural patterns was observed, but no impairment of ovarian cyclicity. Thus, hypergonadotrophic hypergonadism during the hypothalamic differentiation phase gave rise to bisexual behaviour in adult female rats associated with normal ovarian cycles. The question of a direct or indirect influence of gonadotrophins on the sex-specific brain differentiation is discussed.