The Sensitivity of Rat Oocytes to X-rays

Abstract

A re-analysis of already published data (Mandl 1959) shows that normal stage 1 oocytes of the young mature rat survived irradiation according to a typical exponential dose-response relation with D37 = 91 r and n=2.3 [plus or minus] 1.1. When the data for normal plus atretic oocytes are combined, the dose-response relationship for stage 1 is not simple. Oocytes at later stages of fol-licular development were very much more radioresistant. Large doses of radiation increased the proportion of atretic follicles in the earlier stages even as late as 30 days after exposure. In contrast at stages 5-6 doses of radiation too small to affect the number of normal oocytes reduced the number of atretic oocytes to levels much below those in unirradiated controls.