[Sex differences in the secretory activity of the gonads and in their sensitivity to gonadotropins in early ontogenesis of rats].

The secretion of estrogens by the ovaries of foetal (15-19 days of gestation) and newborn rats in organ cultures was not detected by fluorimetry when the ovary was taken prior to the onset of folliculogenesis. The time schedule of the process of folliculogenesis in organ culture corresponded to that in vivo. Estrogens were detected in the medium when folliculogenesis was fully established in organ cultures. The secretion began spontaneously and was not affected by the addition of gonadotropins to the medium. On the contrary, the secretion of androgens by the testes of foetal (17-19 days of gestation) and newborn rats in organ cultures was constantly detected by the competitive protein-binding assay. The addition of gonadotropins to the culture medium increased the level of androgen secretion by foetal and newborn rats.