Aging of the erythrocyte. III. Cation content.

Studies on the main cation content of density-separated bovine erythrocytes showed a progressive decrease in the levels of K+ and Mg2+ with increasing cell density (and age) accompanied by an increase in the level of Na+. The magnitude of net cation loss corresponded to that of red cell volume decrease, but could not account for the total increase in the microviscosity of the erythrocyte interior.