The effect of low dose gamma irradiation on Na+ efflux through human erythrocyte membrane

Human erythrocytes were exposed to 662 keV gamma radiation at doses up to 60 Gy and the Na+ efflux was measured. The Na+ efflux by passive diffusion increased linearly with the dose. Though no clear dose-dependency could be observed, a significant increase in the rate constant, K, of Na+ efflux by the Na+ - K+ pump mechanism through erythrocyte membranes was evident. As sodium transport appeared to be sensitive to irradiation at doses one order of magnitude lower than those which cause membrane lipid peroxidation, we suggest that the effect is due to the damage of protein channels, probably by oxidation of SH groups in the transport proteins (author)