The relationship between the thymus and the sexual organs

Abstract

In male and female albino rats, castrated during their prepuberal period (30 days of age), the thymus was heavier than in the controls during the period between 45 and 250 days of age. The weight increase was due to an actual hypertrophy of the parenchyma. An evident increase was also produced in both sexes by adult castration. The weight curve of the thymus of rats of either sex, castrated during the prepuberal period, was higher, but nearly parallel to that of the normal ones. The shape of the curve was not influenced by castration, therefore the physiological involution is not determined by the development of the sex glands. No differences were evident histologically (either at the beginning, or in the moment of most intense physiological involution) between the thymus of animals castrated during prepuberal period and normal ones. Prepuberal castration produced a slight weight increase of submaxillary, cervical and axillary lymphatic ganglions of albino rats. Their involution began at 160 days of age in castrated as well as in normal animals, and therefore appeared later than the thymic involution.Male hormone injection (testosterone propionate) provoked atrophy of thymic parenchyma of castrated as well as normal albino rats of either sex. Female hormone injection (estrone or estradiol bensoate) gave rise to atrophy of thymic parenchyma of normal and castrated albino rats of either sex. Histological changes produced by either hormone were intense atrophy of thymic lobules with extensive destruction of thymic lymphocytes and increase of connective and principally of fatty tissue. Thyroidectomy decreased the size of thymus already hypertrophied as a result of prepuberal castration in both sexes. In female albino rats, castrated during prepuberal stage, adrenalectomy produced but a slight increase of hypertrophy determined by gonadectomy. © 1940 by The Endocrine Society.