The Gross Manifestations of Continuous Gamma Irradiation on the Prenatal Rat

Abstract

To determine the effects of continuous, low-intensity γ-irradiation on the developing rat, impregnated females were subjected to γ-radiation at 50 R per 20-hour day, beginning on the first day of pregnancy. Prenatal effects were determined by examination of the embryos, fetuses, and uteri on specific days 10 through 20 of gestation. Irradiation at this level did not affect the total number of implantations, but a great increase in mortality was observed at the twelfth day. Most radiation-induced deaths and resorptions occurred prior to the fifteenth prenatal day. As measured by increase in weight and length, the prenatal growth of the irradiated embryo and fetus was greatly retarded. Gross abnormalities in the irradiated late fetus were a reduction in body size, microencephaly, and reduction of spleen weight. Other less generalized abnormalities are described which include anophthalmia, sternal malformations, and edema.