[Effect of simultaneous administration of estradiol and progesterone on the proliferative pool of the uterine and vaginal epithelium in castrated rats].

By the method of autoradiography, the proliferative pool in the epithelia covering the vagina, uterine body and its glands was investigated in ovariectomized rats treated with oestradiol alone and in combination with progesterone, under repeated injections of 3H-thymedine for 24 h. None of the epithelia studied demonstrated the proliferative pool more than 80%. Oestradiol and oestradiol in combination with progesterone produced a considerable increase in the size of proliferating cell population in the vaginal and uterine epithlia in comparison with the control animals. In the vaginal epithelium, progesterone decreased the proliferative pool and inhibited migration of the labeled cells towards the superficial epithelial layer comparing with the injection of oestradiol alone. In the epithelium covering the uterus body, progesterone increased the size of proliferative cell population and delayed their rejection into the uterus cavity. In the epithelium of the uterus glands, there was no statistically significant differences in the amount of labeled cells by the end of the experiment both after oestradiol injection and after simultaneous injection of oestradiol and progesterone.