EFFECTS OF X-IRRADIATION ON DIFFERENTIATING LEYDIG CELLS OF THE IMMATURE RAT

Experiments were designed to determine whether x irradiation affects subsequent production of androgen, whether subsequent response of testis to gonadotropin is impaired, and whether accessory sex organs are affected. Male rats were exposed to 400, 800, or 1200 r at varying ages after birth (3 to 36 days). The subsequent secretory capacity of the testis, as judged by the weight of the accessory sex organs, was markedly impaired following irradiation. The effect of x irradiation on the secretory interstitial (Leydig) cells depended on both the dose of x rays used and the age of the animals at the time of exposure. The reduction in the secretion of androgen was associated with a decrease in the volume of intertubular tissue. The secretory cells became progressively more radioresistant as the animals neared the age of puberty. The ability of Leydig cells to respond to exogenous gonadotropin was diminished by irradiation. In contrast, the response of the accessory sex organs to exogenous androgen was not appreciably affected. The observations suggest that: the Leydig cells of the immature animal may be more radiosensitive than those of the adult; irradiation may modify the response of interstitial cells to gonadotropin; and destruction of the seminiferous epitheliummore » may induce an imbalance in the levels of endogenous gonadotropins. (H.H.D.)« less