Morphometric investigations on endocrine glands. VII. The influence of some estrogens on the formation of castration cells in the anterior pituitary of rats.

After ovarectomy there are observed changes in body weight increase, uterus weight and area size of the gonadotropic cells in the adenohypophysis. A replacement by estrogens may diminish such variations, but their extent is different for each of the single parameters; therefore no high correlation coefficients resulted in calculations on the basis of all data of a test. The administration of estradiol benzoate, estriol and estrone twice a week (about once per cyclus period) caused moderate changes in body weight increase and marked differences in uterus weights, but in the tested doses no alteration in the cell size of the gonadotropes, compared to ovarectomized animals without further treatment. Daily application of different doses of estradiol benzoate or estrone signify a higher efficacy of the first steroid. Different treatment conditions - starting shortly after excision of the ovaries or one week later - yielded only slight divergencies. Progesterone injected together with estrone caused no further significant deviations. Mestranol had only a moderate effect on the gonadotropes, but the uterus weight may increase under such a replacement up to values similar to those in untreated animals. On the other hand, there was observed a marked shrinking of the gonadotropes following higher doses of estriol, but in this case the uterus weight was less affected. In relation to equal doses of estrone, the uterus weights are similar following estrone cyanate, but in contrast to the parent compound, the effect on the gonadotropes was only low.