Oxygen release kinetics in healthy subjects and diabetic patients. I: The role of 2,3-diphosphoglycerate.

ABSTRACT

Glycosylated hemoglobin (HbA1c), found in higher concentration in diabetic patients (average 9% versus 5% in healthy subjects), has an approximately ten-fold higher oxygen affinity than non-glycosylated hemoglobin (HbA0). But the oxygen affinity in blood from diabetic patients does not differ from that in healthy subjects. Thus, it was concluded that 2,3-DPG, which lowers the oxygen affinity of hemoglobin by stabilizing deoxyhemoglobin and which is increased in diabetic patients, compensates for the effect of HbA1c. Therefore, oxygen release kinetics of hemoglobin in diabetic patients (HbA1c = 9.3 +/- 0.3%) and healthy subjects (HbA1c = 5.2 +/- 0.3%) were compared and the influence of 2,3-DPG determined using the stopped flow technique. The oxygen dissociation rate constant (k) of hemoglobin from the two groups did not differ (diabetic patients, 64.4 +/- 3.1 s-1 and healthy subjects, 65.1 +/- 2.3 s-1). Addition of supraphysiological concentrations of 2,3-DPG produced physiologically insignificant changes in this parameter. It is concluded that 2,3-DPG may not be the major factor compensating for the effect for HbA1c on oxygen release in diabetic patients.