HISTOCHEMICAL STUDIES ON THE HUMAN TESTES, ESPECIALLY ON THE INTERSTITIAL CELLS OF LEYDIG

Abstract

The testicular tissue of forty men of various ages and conditions was examined both histochemically and histologically. 3β-Hydroxy steroid dehydrogenase (3βOHSD) was demonstrated in nothing but interstitial cells of Leydig (ISCs) in the human testicular tissue. Every ISC of fetal testes equally exhibited the enzymatic activity, which rapidly disappeared during the first neonatal week and could not be found histochemically till the onset of puberty. At the time of puberty, almost all the ISCs acquired the evident activity again. In the postpubertal testes, however, the regressive ISCs, which increased in number as age increased, had no activity. 3βOHSD was also active in the proliferative ISCs of postpubertal testicular atrophy, gonadotropin treated cryptorchism and testicular feminization, while there was no activity in the testes of eunuchoidism, diabetes insipidus and estrogen-treated prostatic carcinoma. The appearance of esterase and acid phosphatase in the ISCs roughly paralleled 3βOHSD-activity. In seminiferous epithelium, both the enzyme were usually weak and independent of sexual maturation. The activities of both diaphorases, lactate dehydrogenase and glucose-6-phosphate dehydrogenase were usually very intense in the ISCs in every case examined. Especially, the fibroblast-like cells in the interstitium of the infantile testes were identified as immature ISCs, because of their strong activities of these enzymes. On the contrary, the seminiferous epithelium showed very weak activities of these enzymes in fetal testes, and moderate in postnatal ones. The appearance of alkaline phosphatase in the ISCs was limited to the aged, gonadotropin-treated cryptorchism, estrogen-treated prostatic cancer and testicular feminization. On the other hand, this enzyme was very intense in the undifferentiated germ cells of fetal testes, while it was hardly found in the seminiferous epithelium of postnatal testes.