Ovarian development and fertility of the progeny of mice irradiated before mating

Bagg mice were irradiated with 300 R x-ray ( F0 mice), and mated immediately afterward. The development of the ovaries and the fertility of their female offspring ( F1) was investigated. The ovaries of the F1 mice showed early signs of aging but the number of oocytes was not altered. The fertility of the F1 mice was different from the normal. The F1 mice produced more young than the control animals. The mortality rate was higher in the F1 mice, many dying with mature embryos in utero, apparently unable to give birth. It is reasoned that the observed changes are probably not due to genetic damage but rather to an altered maternal hormonal milieu initiated by radiation of the F0 animal.