The effect of ionic strength on cell volume, cell pH and cellular buffer capacity in human red blood cells

The effect of ionic strength on the properties of high molecular weight molecules in human red cells is described. The ionic strength was varied by dialysis of freshly drawn red cells against various KCl solutions in the presence of the ionophore nystatin. Nystatin increased the membrane permeability rather unspecifically towards both monovalent cat- and anions. The membrane permeability towards molecules with an Stokes-Einstein radius of more than 4 A was unaltered. With increasing ionic strength the cellular pH and the cellular volume increased, while the cellular buffer capacity decreased. The variation of the chloride distribution ratio with pH at various KCl concentrations is given in a tabulated form.