The Effects of Prenatal Radiation on Postnatal Development in Rats

One hundred and twenty-four litters of rats were used in a study of the effects of prenntul irradiation (Co/sup 60/) on the viability and growth of the irradiated individuals. The neonatal death rate was siguificantly higher in litters exposed to 110 r on days 13 to 15 (27%, P <0.001), on days 16 to 18 (13%, P <0.05), 150 r on day 14 (98%, P <0.001), and 220 r on days 12 to 16 (77%, P <0.001) of gestation as compared to control litters (6%). The majority of postnatal deaths occurred by the seventh day. The viability was not affected in litters exposed to 150 or 220 r on day 20. The average weaning weights of all the irradiated groups were lower than the weight of the control group. When bred to normal males, no difference was found between control and prenatally irradiated females in per cent of fertile females, per cent of conpora lutea as represented by living fetuses, or fetal deaths. Ovulation was approximately 20% lower in the irradiated than in the control females. Mature body and testes weights of irradiated males were significantly lower than for control males (P <0.001). The degree of retardation in testes weightsmore » was dependent on level of radiation and stage of gestation nt time of irradiation. (auth)« less