The Effect of Hypoxia on Radiation Life-shortening in Drosophila Melanogaster

Summary

Radiation-induced life-shortening in Drosophila melanogaster has been measured. Flies were irradiated at a dose-rate of 1430 rads/sec whilst breathing various mixtures of oxygen and nitrogen. Neither a detectable age dependence nor a sex difference was noted. There was no difference in sensitivity with oxygen contents of 6–21 per cent; under 100 per cent nitrogen, life-shortening was reduced. This difference in sensitivity was due to an increase in the plateau region at low doses for nitrogen. For higher doses inactivation constants for both sets of curves were similar Thus the o.e.r. was dependent on the level of damage. For the acute effects of radiation there was no protection under nitrogen. This study is relevant to the effects of radiation on post-mitotic normal tissue.