Copyright #{174}1973 by The Society for the Study of Reproduction All rights of reproduction in any form reserved. Testicular Function at Puberty Following Prepubertal Local X-lrradiation in the Rat

Rats whose testes were X-irradiated at 27-28 days of age were examined at 73-74 days of age. Spermatogenesis was severely retarded, and testis weight was one-sixth that of controls. Accessory sex organs were markedly lighter. Pregnenolone conversion by testis homogenates was reduced, and the activities of i1’-3-hydroxysteroid dehydrogenase + t.’- isomerase and 17p-hydroxysteroid dehydrogenase in the microsomal fraction were severely depressed. Treatment with HCC for 15 days restored accessory organ weights and the testicular enzyme activities related to androgen formation almost to the control level, but did not affect testis weight or spermatogenesis. Radiosensitivity of the testicular intersti-tial cells of prepubertal and mature rats were discussed. In adult rats, X-irradiation of the testes with 1500 R caused a marked reduction of androgen production by testicular homogenates at 20 days postirradiation (Berliner et at., 1964). However, addition of an NADPH-generating system in vitr