Enhanced radiation damage to the erythrocyte membrane in the presence of azide and other anions.

Radiation-induced potassium loss from erythrocytes and haemolysis were enhanced by the presence of azide at the time of exposure. The enhancement occurred with post-irradiation incubation at 37 or 4 degrees C, but was inhibited by formate or ethanol. Other anions, which produce radicals known to react selectively with only a few amino acids, gave rise to a similar but lesser enhancement. It is proposed that azide radicals are more effective in producing erythrocyte damage than the OH radicals from which they derive, and that the azide radical should be regarded as another selective secondary radical. The data can be used to infer differences in the mechanisms of damage leading to potassium loss or haemolysis.