Effects of pre-ovulatory X-irradiation on fertilization, initial cleavage and post-nidation development in the Chinese hamster.

In order to investigate the effects of pre-ovulation X-ray radiation on fertilization, initial cleavage and post-nidation development, Chinese hamster dams were mated with normal males after exposure to 200 rads of radiation during the primary maturation period, and cytogenetic studies were performed at 2.5, 3.5 and 10 days after fertilization; comparison studies were also performed on an untreated control group. The results indicated that: (1) The ovarian ova with chromosomal anomalies induced by X-ray radiation had the ability to be fertilized and transmit the abnormality to the 2-celled stage, but most of them deceased by the 8-celled stage. (2) The embryos attaining the 8-celled stage with normal chromosomes were implanted and survived, but showed remarkable hypoplasia on day 10 of gestation.