The synthesis of estradiol and progesterone receptors in relation to the biological effects of sex hormones in ovariectomized rats

: The concentration of the estradiol and progesterone receptors in cytosol increased within a week after ovariectomy in rats, the nucleic concentration of receptors sharply diminishing. The uterus atrophy following ovariectomy in associated with a reduction of both nucleic and cytosol receptors in the organ. Administration of estradiol (1 mg) restored the organ mass and the character of hormonal reception within a week. Progesterone and clomyphen exerted some uterotropic effect. Ovariectomy reduced the creatinkinase activity by 2.9 times and the peroxydase activity by 13 times. Two types of synthesis of female sex hormones receptors seem to exist in the rat uterus: the constitutional type depending on no hormonal effects and the induced one depending on the sex steroids, estradiol in particular.