Mean red cell age as a determinant of blood oxygen affinity.

Abstract

LOOSENING of the bond between haemoglobin and oxygen promotes the release of oxygen to the tissues and thus compensates for hypoxia. Such a decrease in blood oxygen affinity occurs in the principal types of hypoxia1–12, presumably because of an adaptive increase of red cell organic phosphates, especially 2,3-diphosphoglycerate13–17. In the natural ageing of normal human red cells, there are changes in the electrostatic interactions involving haemoglobin which bring about an increase of the affinity of haemoglobin for oxygen18. Glutamic oxaloacetic transaminase (GOT) is active only in younger red cells and is a better and more stable indicator of mean red cell age than reticulocyte counts19,20. Using red cell GOT activity as such an indicator of age, we have investigated the relationship between mean red cell age and both red cell DPG and oxygen affinity.