THE RELATION BETWEEN PHOSPHATE METABOLISM AND THE TRANSPORT OF CATIONS ACROSS THE CELL MEMBRANE IN THE HUMAN ERYTHROCYTE

The rate of passage of cations across the red cell membrane, in the direction of the respective ionic gradients, in blood preserved with glucose at 4 °C, is not diminished upon the addition of inosine, notwithstanding the induced formation of substantial amounts of phosphate esters, including ATP, in the cells. The movement of cations, however, is retarded on the addition of glucose or inorganic phosphate, and on increase in the concentration of hydrogen ions. It would appear, therefore, that the movement of cations across the membrane, at 4 °C, is influenced little, if at all, by the metabolic activity of the cell.When the temperature of the preserved blood is returned to 37° the rate of movement of cations across the cell membrane against their respective gradients is greatest in cells which had either been preserved or have been incubated with inosine even if the remainder of the inosine has been removed. Inosine is more effective than glucose in bringing about the restoration of cation composition in preserved red cells at 37°. The degree of restoration is greater in the presence of glucose than in its absence. Arsenate inhibits the transport of cations against the gradients. Evidence is given that the capacity of the cells to restore the cation distribution at 37 °C is determined largely by the concentration of the phosphate ester intermediates.