[Gonadal endocrine function indicators during initial stages of postnatal ontogenesis of the female sable]

By means of radioimmunoassay, 17 beta-estradiol-, androgen- (testosterone and dihydrotestosterone) and progesterone contents were determined in the peripheral blood of the female sables, aged 2 to 27 months, during postnatal ontogenesis initial stage. Under the action of seasonal factors steroid level was sharply decreased in the animals of the all ages within the autumnal period, whereas the gonadal function activation lowered over a period of February and March, when "the spring animation" of wild stables is seen. An increase in the sex hormone level was more pronounced in females over one year old. The compared concentrations of hormones, studied in the 5-months' females (the growth stopping). 14 to 17-months' animals (the 1st year reproductive period) and 27-months' stables (the 2nd year reproductive period) were close to those of 17 beta-estradiol and progesterone contents in fertile animals. It is suggested that the sexual system of the 5-months' females is ready for the reproductive processes but their secretory activity is sharply reduced, probably under the seasonal factor influence.