The Influence of Hormones on Breast Hyperplasia and Tumor Growths in White Rats

Abstract

Listen

Translate article

In a previous communication (1) dealing with benign fibro-adenomata of the rat's breast, morphologic changes appearing in the transplanted tumors were described. From time to time there occurred variations in the rate of growth, and in the size and consistency of the growing transplants. Differences in the proliferative ratio of stroma and glandular substance also appeared. These changes seemed to be associated with factors relating to sex, to the age of the animal at the time of inoculation, and to pregnancy. The relationship of age, sex, and other factors to the origin and growth of spontaneous and transplanted malignant tumors in mice is discussed by Woglom (2). He quotes Gierke (3) to the effect that young mice (before puberty had supervened) were as suitable as older animals for transplanting tumors, and mentions Loeb (4), Ehrlich (5), Gierke (3), and Lewin (6) as finding no difference in susceptibility between males and females. The influence of gestation and lactation is also mentioned, but here the observations are contradictory. No reference is made to the role of the above factors in benign tumor growth. The present report attempts, in the first place, to determine whether endogenous hormonal factors play a role in experimentally produced benign fibro-adenomata of the rat's breast, growing in animals of different age groups, different sexes, and during pregnancy and lactation. A further study deals with results in male and female castrates, while other series of experiments were undertaken to determine the effect on transplanted tumors and on normal breast tissue of exogenous hormones injected subcutaneously in white rats. I. Endogenous Hormonal Factors The Age Factor: As previously mentioned, the age of the animal at the time of tumor inoculation influences the morphology of the implanted benign fibro-adenoma. The age of the animal from which the tumor is derived and the age of the tumor must also be taken into consideration.