Termination of the hormone-sensitive period for differentiation of the sexually dimorphic nucleus of the preoptic area in male and female rats.

摘要: Abstract The volume of the sexually dimorphic nucleus preoptic area (SDN-POA) in rat brain is several-fold larger males than females. SDN-POA can be influenced significantly by hormone milieu during early postnatal life. purpose present study was to identify when termination sensitive period occurs which exogenous androgen administration influences gonadectomized on first day life (fales) or intact Analysis fales showed that testosterone propionate (TP, 500 μg) treatment days 2, 3, 4, 5, increased its over values from oil-treated fales. In contrast, TP 6, 7, 8, failed increase volume. A similar pattern observed females treated with TP. Females (500 a significant compared oil-injected animals, while same resulted no such enhancement. absolute and relative change following greater We conclude (1) development action through 5 then abruptly becomes insensitive this dosage TP, (2) although temporal response females, exposure postnatally results consistently male female's. This may due prenatally endogenous males.