The Age Dependence of Radiation Sensitivity of the Gonads of Female Mice

Abstract

Female CBA-mice were continuously gamma-irradiated with 0.9 or 2.4 Gy. The dose was given during a 4-day period with start at 50, 90, 135 or 190 days of age respectively. Fifty-six days after the irradiation the females were killed and the number of germ cells in their ovaries were compared with that from unirradiated control females of corresponding age. The total number of germ cells was, compared with the controls, reduced by about 70% in all age groups after the dose of 0.9 Gy and to between 3 and 8% after 2.4 Gy. Seven stages of oocyte development were observed as well as 2 stages in degeneration. The observations suggest a changing radiation sensitivity by age during an initial period of about 90 days followed by a period of fatal radiation effects.

Key Words:

• Radiobiology
• mice
• gamma irradiation
• female germ cells
• age dependence