Neuronal death in the developing sexually dimorphic periventricular nucleus of the preoptic area in the female rat: effect of neonatal androgen treatment.

Neonatal treatment of female rats with androgen decreases the nuclear volume of the anteroventral periventricular nucleus of the preoptic area (AVPv-POA). In order to examine the effect of androgen on the neural substrates in the developing AVPv-POA which show a sexual dimorphism in nuclear volume, the cell death pattern in the AVPv-POA was compared between normal females and androgenized females. Wistar female rats were treated with 50 micrograms of testosterone propionate (TP) for 5 days from the day of birth. Degenerating cells (pyenotic cells) and normal cells were counted in every third section from days 1 to 13 of life. The rate of pycnotic cells to 1000 cells in TP-treated females sacrificed at days 7 and 10 was significantly higher than that in normal females. These results may suggest that neonatal androgen regulates neuronal death in the AVPv-POA, decreasing the number of neurons in the nucleus.