SUPERPREGNANCY FOLLOWING PREFERTILIZATION X IRRADIATION OF THE RAT
The early and late effects of a single whole-body exposure of 400-r x rays on reproduction were studied in rats exposed during various stages of the estrus cycle prior to mating. The early effects in females that mated during the flrst expected estrus after irradiation seemed to involve superovulation, the greatest response occurring in females irradiated during metestrus (M) or early diestrus (M + 1). Implartation rates were increased in all groups of fumales except those which mated half a day after irradiation (M + 3B). Average litter size was highest in females irradiated during metestrus or early diestrus. Those females irradiated during late diestrus (M + 3 and M + 3A) had litters which were comparable to control size, whereas the litters were more or less completely resorbed in females that mated half a day after irradiation. Though the numbers of corpora lutea were still increased up to at least 171/2 days after exposure, the number of implantations and of 20-day fetuses, was comparable to cortrol values in females that mated after the first expected estrus (late effects). Fetuses, under both early and late effects, were normal in size and development. The most significant observation is the induction of superpregnancies in rats by exposure to x irradiation, particularly in M and (M + 1) females. These findings are unexpected from data on fertilization before and after x irradiation and subsequent embryonic mortality in the mouse, and the fact that 500 r is just sublethal in the rat. These differences between the mouse and rat are probably due to the fact that the mouse ovary is more sensitive than the rat ovary to ionizing radiation. (BBB)
- Research Organization:
- Univ. of Rochester, N.Y.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-18-017539
- OSTI ID:
- 4050353
- Journal Information:
- J. Reprod. Fertility, Vol. Vol: 7; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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