Effect of irradiation on red cell cation content and transport.

The effect of irradiation on red cell (RBC) cation content and membrane transport was studied. When units of RBCs collected in AS-1 (n = 8) were exposed to radiation (2000 cGy) and then stored at 4 degrees C, there was a significant increase in external K and internal Na and a decrease in internal K relative to control units (n = 3). Similar changes in internal cation contents were noted for RBCs collected in CPD; because of the higher hematocrit, the external K concentration was higher than that in AS-1-collected RBCs. Cellular K loss and Na gain were balanced, and the total cation content remained constant; however, both control and irradiated cells swelled over time as a consequence of the decreased pH and 2.3 DPG content. These changes in volume and cation content were reversed when the cells were incubated at 37 degrees C. A specific effect of radiation on the Na-K pump and Na-K-Cl and K-Cl cotransport systems was ruled out, because no significant differences between irradiated cells and controls were found. These data indicate that radiation induces an increased permeability to Na and K on the part of the RBC membrane lipid bilayer and that this increase is balanced and reversible.