Endocrine Reactions in Female Rats after X-Ray Treatment of the Ovaries. ∗

Abstract

X-ray sterilized rats with completely destroyed germ cells but well preserved somatic elements of the testis, fully maintain their secondary sex characters. 1 They react like total castrates when united in parabiosis with untreated females. This was taken as evidence that the X-ray sterilized male, like the castrate, produces large amounts of follicle stimulating hormone of the anterior pituitary. So-called castrate cells are found in the hypophyses of X-rayed males, though in smaller numbers than in surgical castrates. Parkes 2 first observed that X-ray sterilized female mice in many instances maintain fully their secondary sex characters including the cyclical oestrus changes. Ford and Drips 3 later reported experiments on rats which led to similar general conclusions. We endeavored to correlate the ovarial changes with the hypophyseal reactions. The main results and conclusions can be summarized as follows:

According to the extent of damage of ovarial structures observed at 4 to 7 months after irradiation the females can be divided into 2 groups. In both the germ cells have completely disappeared but the follicular apparatus—cystic follicles, corpora lutea—is partly preserved in the ovaries of the first group and completely destroyed in those of the second group. Ovaries of the second group show a profuse proliferation of epithelial cells from the germinal epithelium which never become organized into follicular structures. In addition, small “anovular follicles” may arise from the same source, though they soon disintegrate without ever exhibiting cystic transformations.

Females of Group I, 12 cases, observed over periods up to 7 months after irradiation, maintained fairly well the cyclical oestral changes observed in vaginal smears. Periods of 3 to 6 cycles of normal lengths usually were alternating with periods of prolonged oestrus or, less frequently, by prolonged dioestrus.