THE EFFECTS OF CHORIONIC GONADOTROPIN IN ADULT MEN: INCREASED ESTROGEN AND 17-KETOSTEROID EXCRETION, GYNECOMASTIA. LEYDIG CELL STIMULATION AND SEMINIFEROUS TUBULE DAMAGE*
CHORIONIC gonadotropin is known to stimulate growth and endocrine function of the immature human testis. When administered to cryptorchid boys, it can produce enlargement and descent of the testis and, with sufficient amounts, sexual development. In hypogonadotropic eunuchoids, it produces differentiation and growth of Leydig cells and secretion of androgen (1). Little information is available, however, regarding the effects of chorionic gonadotropin on the mature human testis. The purpose of this study has been to determine the effects of chorionic gonadotropin on the structure and function of the adult human testis. During the course of the investigation, an increase in estrogen excretion was regularly observed when the hormone was administered to men having functioning testes. The source of the estrogen, therefore, became one of the major problems of the study. Previous investigations have indicated that the testis is a major source of estrogen in men: castration results in a drop in urinary estrogen level (2), eunuchs and eunuchoids excrete less than normal amounts of estrogens (3, 4), and estrogen has been recovered from human testes (5). Whether this estrogen arises from Leydig, Sertoli, or germinal cells, however, has remained largely in the realm of speculation, although some conflicting information on this problem has been obtained from studies of testicular tumors and human hermaphrodites. Huggins and Moulder (6) observed feminization of a male dog having a testicular neoplasm, which they diagnosed as a Sertoli cell tumor, and concluded that the Sertoli cells produce estrogen; Berthrong, Goodwin and Scott (7) reached the same conclusion from the study of a similar dog tumor. Teilum (8), studying human testicular and ovarian tumors, and Witschi and Mengert (9), studying the gonads of an hermaphrodite, also concluded that the Sertoli cells produced estrogen. On the other hand, Hunt and Budd (10), who observed gyneco-mastia in a man with a Leydig cell tumor, and Nelson (11), who studied the gonads of 5 “feminine” pseudohermaphrodites, presented evidence that the Leydig cells were the source of estrogen in these individuals.