Comparative studies of oxygen equilibria of human adult and cord blood red cell hemolysates and suspensions

Abstract

The oxygen equilibria of suspensions and hemolysates of human adult and cord blood erythrocytes have been compared. Dialyzed hemolysates of adult and cord blood red cells showed small, but distinct, differences in the Bohr effect. Changes in phosphate molarity of the buffer used for the dialysis resulted in identical changes in oxygen affinities. Suspensions of cord blood erythrocytes in 0.9 g % NaCl showed a marked increase in oxygen affinity when compared with similar suspensions of adult red blood cells. The same difference in the Bohr effect was observed as seen for dialyzed hemolysates. The oxygen equilibria of concentrated undialyzed hemolysates of cord blood erythrocytes were almost identical to those of cord blood cell suspensions; the Bohr effect, however, was increased. The equilibrium between oxygen and the corresponding adult hemolysates was notably changed; the affinities of these hemolysates were found higher than that of either cord blood cell suspensions or hemolysates. The oxygen affinities of red cell suspensions from a heterozygous carrier of the persistent high Hb-F anomaly with 34% Hb-F were indistinguishable from those of normal adult erythrocyte suspensions. The addition of notable quantities of KCN and of NaF to the 0.9 g% NaCl solution did not affect the oxygen affinities of suspensions of both adult and cord blood erythrocytes. Hypotonic cell suspensions (in 0.6 g% NaCl) demonstrated increased oxygen affinities and a slight decrease in the Bohr effect; the effect of hypotonicity was the same for both cell types. Treatment of cord blood erythrocytes with a hypertonic solution (2.5 g% NaCl) resulted in decrease of the oxygen affinity. A similar treatment of adult erythrocytes increased the oxygen affinity, especially at pH values of 6.9 and higher. The significance of these findings has been discussed. Our studies suggest that differences in cell membrane or cell organization may likely contribute to the observed difference in oxygen affinities of human adult and cord blood erythrocytes. The presence of a specific fetal hemoglobin in the erythrocyte influences the Bohr effect and possibly the pH inside the cell, but not the oxygen affinity.