Dose and time related responses of the irradiated prepubertal rat testis. II. Seminiferous epithelial function

Dose-related effects of radiation upon the seminiferous epithelium were examined in the prepubertal rat. Marked damage to the spermatogenic cell populations was produced by doses of 5 Gy and above. As a result serum levels of FSH were increased, maximum changes being observed at 2 weeks, but levels remaining high even at 36 weeks after irradiation. Serum levels of androgen binding protein (ABP) were inversely related to serum FSH. Above a threshold dose of 5 Gy, serum ABP levels were reduced to between 30-50% of control values, possibly indicating damage to the Sertoli cells. Progression in the degree of testicular failure was indicated at 36 weeks after a dose of 15 Gy by further increases in serum gonadotrophins when compared to earlier times and by the absence of spermatogenesis.