Effects of neonatal ovarian X-irradiation in the Chinese hamster. I. Correlation between the age of irradiation and the fertility span.
The fertility span between the first and the last estrus was compared among female Chinese hamsters exposed to 1 Gy X-rays on neonatal day 0, 2, 4, 6, 8, 10 and 14. The fertility span changed dramatically according to the age at the time of irradiation. The females irradiated on day 4, 6 and 8 showed a definite delay in sexual maturation and a very early cessation of the estrous cycles, while those irradiated on day 10, 2 and 14 (in this order) showed a much longer, nevertheless significantly shortened, fertility span. Reduction in the number of juvenile oocytes by acute killing was responsible for this shortened reproductive life. The present study indicated again that the sensitivity of the oocytes to the lethal effects of X-rays is unquestionably meiotic stage-dependent.
Tateno
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D000818:Animals; D000831:Animals, Newborn / Q000528:radiation effects*; D006224:Cricetinae; D005260:Female; D005298:Fertility / Q000528:radiation effects*; D009865:Oocytes / Q000528:radiation effects; D010053:Ovary / Q000528:radiation effects*; D011836:Radiation Tolerance