| Abstract: | The role of testosterone in the early stage of spermatocytogenesis was investigated in newborn rats. The testes of rats, either 0 or 6 days of age, were implanted into those of hypophysectomized adult rats that had or had not been injected with testosterone propionate (TP) after hypophysectomy and also into those in intact adult rats. All the animals were autopsied 17 or 11 days later when the implanted testes reached 17 days of age. The implanted testes were examined for cellular components in the seminiferous tubules. In an additional experiment, newborn rats were injected with TP or cyproterone acetate, an antagonistic substance against androgen, daily for the first 17 days of life and examined for testes. Proliferation of supporting cells and development of seminiferous tubules were less remarkable in the testes of newborn rats which had been implanted into the testes of hypophysectomized rats than in those which had been implanted into the testes of intact adult rats. Proliferation of supporting cells was not stimulated by TP, but development of seminiferous tubules was slightly promoted. Progress in spermatocytogenesis from gonocytes to pachytene primary spermatocytes was observed in the testes of newborn rats which had been implanted into the testes of hypophysectiomized rats. It was not so marked after injection with TP. These results suggested that testosterone might have stimulated development of seminiferous tubules and maturation of spermatocytes in the early stage of spermatocytogenesis by its synergistic action with a gonadotropin, possible follicle-stimulating hormone. |
