Effect of x-irradiation on the endocrine function of the canine testis.

Abstract

Observations were made in dogs to determine whether X-irradiation affects the secretion of androgens by the testes, and their responses to exogenous gonadotrophin. The secretory activity was, under pentobarbital anesthesia, determined by measuring 17-oxosteroids in spermatic vein blood. The radiation was applied with 200 or 2, 000 R only to the testes, but it failed to stimulate or significantly alter the secretion of 17-oxosteroids in a period of up to 4 hr after exposure. However, at 200 R an increased secretion of testicular 17-oxosteroids into the spermatic vein became evident within 1-6 days, whereas after 2, 000 R it was observed within 13 days only in a few cases. During the post-irradiation period of 30 days, irradiated testes responded to pregnant mare serum in doses of 40iu/kg by producing larger amounts of 17-oxosteroids than normal, the maximum response occurring within a few days following irradiation. In connection with these experiments, enzyme histochemical studies were carried out on the activity of secondary alcohol dehydrogenase in the testicular tissue. At 200 R, the enzyme activity in the Leydig cell areas was increased considerably and attained to the maximum in a faw days after irradiation, and was then progressively reduced.