DOES RADIATION AGE OR PRODUCE NON-SPECIFIC 



LIFE-SHORTENING? 



E. H. MOLE 

 M.R.C. Radiobiological Research Unit, England 



SUMMARY 



The older mice are at the time of irradiation the less the life -shortening effects of 

 single exposures to radiation and of daily irradiation for the duration of life. Since 

 natural ageing and radiation-induced Ufe-shortening were not additive, it seems unlikely 

 that radiation causes non-specific life-shortening in the sense that it ages the organism in 

 some general over-aU way. 



The phenomenon of ageing is very general indeed so that even one exception 

 to the popular generalization that radiation causes non-specific ageing may 

 throw real doubt on the validity of the generalization. 



1000 



500,1- 



o 



'-v^ 





?. 



D— a 



60 

 270 

 470 



670 

 870 



D 



O 



Q. 







600 

 Dose (rad) 



1000 



Fig. 1. Mean survival time of female CBA mice, survivors of single X-ray exposures in the 

 acutely lethal range given at varying ages as shown. 



In an as yet, unfinished series of experiments by Mole and Thomas (1961) 

 the survival time of female CBA mice aged 70, 270, 470, 670 and 870 days has 

 been determined after single doses of X-rays in the LD50 range (Fig. 1) or 

 during continuous y-irradiation at 10 r nightly (Table I). Seventy- and 470- 

 day-old mice have also been compared at daily doses of 15, 30 and 50 r 

 y-rays and 2 rads of fast neutrons. 



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