Increased Susceptibility of Rabbits to Brown-Pearce Epithelioma Induced by Estrogens in Human Pregnancy Urine

Numerous investigators have studied the role played by sex hormones in the pathogenesis of various kinds of new growths of animals. The data that have been obtained, however, do not lead to concordant conclusions. Bischoff and Maxwell (1) tested the influences of physiological doses of prolan, estrin, and placental and pituitary gonadotropic extracts upon the rate of growth of the R-10 tumor in rats, and reported negative results. Tanzer (2) has stated that mouse sarcoma 180, after being exposed to prolan in vitro prior to inoculation, showed no evidence of inhibition or acceleration in growth. Sugiura and Benedict (3) observed that theelin, theelol and emmenin exerted no stimulating or retarding effects on the growth of carcinoma, sarcoma and melanoma in mice. Emge and Murphy (4) found that the growth rate of mammary adenofibroma of white rats was not materially altered by repeated pregnancies. Lacassagne (5) and others (6) demonstrated that the administration of estrin favored the production of cancer in mice. Gross (7) observed that pregnancy urine hastened the development of sarcoma in mice, and induced the formation of metastases. Perry and Ginzton (8) and Gilmour (9) found that the susceptibility of the skin to the development of cancer in response to carcinogenic agents of the hydrocarbon group was enhanced by theelin.