A Study of Human Red Blood Cell Permeability

In their recent studies (20) on the water and electrolyte distribution between cells and serum, Van Slyk‘e, Wu, and McLean assumed for their theoretical considerations that the red hlood cells were impermeable to the cations sodium and potassium. They showed that when the serum anion concentration was changed in .whole blood COz saturation experiments, the reestablishment of electrolyte equilibrium could be entirely accounted for by the transfer of water and anions across the cell membrane. Several previous investigators (5, 6, 11, 12, 18) had reported similar findings in COz saturation experiments; but Hamburger (8, 9) found that when the concentration of the cations in the serum was changed by adding sodium or potassium salts or water to whole blood, both basic and acid ions appeared to traverse the cell membrane in the electrolyte readjustment. At present, therefore, since Hamburger’s latter findings stand undisputed, any assumption of the impermeability of the red blood cells to sodium or potassium seems open to doubt. Since this question is of fundamental importance to an understanding of electrolyte equilibrium, the present writers have repeated some of Hamburger’s experiments using the more refined laboratory procedures that have been recently acquired, because it was believed on theoretical grounds that the red blood cells were impermeable to cations within the limits of electrolyte change found in human disease. They found that when the electrolyte equilibriun was disturbed by the addition of salt or water to blood even beyond the extreme limits of variation recorded in human blood, the red blood cell membrane apparently remained impermeable to the cations sodium and potassium.