Effects of continuous gamma-irradiation during whole reproductive period on mouse ovary

Long-term effects of continuous gamma-irradiation with a dose-rate of 6 R/day were studied of mouse ovaries which had been irradiated during whole reproductive period, namely from conception until adult age. In the non-irradiated control group age-related changes were observed in their ovaries from 35 to 400 days of age. In the irradiated group, severe histopathological damages were detected in the ovaries. At 35 to 65 days of age, only a few abnormal oocytes were counted in their ovaries. All the females had permanent sterility (the accumulated dose of 330R), and ovarian tumours appearred at early ages (120 days old) as compared to controls (400 days old). The irradiation experiments for a limited period of mice's life-span showed that the irradiation during the suckling period (from birth to weaning) induced a permanent sterility, while the irradiation during the foetal period or the weaning-juvenile period resulted in a partial deletion of oocytes and a partial decrease of ovary weight.