Induction of Sterility in Male Mice by Chronic Gamma Irradiation

Male CBA inbred mice exposed to radium γ rays at a dose-rate of 33·3 r/week showed a decrease in fertility with the following characteristics: onset, 330 r; median dose, 430 r; 100 per cent dose, 550 r. At a dose-rate of 8·0r/week a 200 r dose induced sterility in 39 per cent of the mice. At a dose-rate of 1·64 r/week, a 40 r dose was followed by a slight (14 per cent), but probably real, increase in sterility which may have been brought about by acceleration of the normal ageing processes. CBA males may be more sensitive than other inbred mice to radiosterilisation.