Reproductive and hormonal function of rat testes under continuous internal irradiation

Selectivity and specifity of incorporated radioactive compounds in different structure levels change kind, degree and intensity of the injury in the reproductive organs. Thus it is necessary to differentiate between direct and nondirect radiation effects. In male rats the reproductive and hormonal function of the testis was examined under conditions of a single incorporation of 75Se-methionine; the animals were paired during the whole time of the experiment (18 month) with normale females of reproductive age. The testicular tissue was investigated by means of light and electron microscopy. Plasma testosterone was determined radioimmunologically. The males were unfertile from 1.5 up to 12 months after application of 75Se. Histologically no visible destruction of the spermatogenic epithelium could be found, but the Sertoli and Leydig cells revealed ultrastructural changes. The concentration of plasma testosterone was diminished and the sexual activity of the animals was disturbed. It is supposed, that a single incorporation of 75Se-methionine in a quantity producing an absorption dose of nearly 1 Gy in the testes during a 6 month irradiation time, produces an indirect disturbance of the spermatogenesis. (author)