OXYGEN RELEASE KINETICS IN HEALTHY-SUBJECTS AND DIABETIC-PATIENTS .1.THE ROLE OF 2,3-DIPHOSPHOGLYCERATE

Glycosylated hemoglobin (HbA(1c)), found in higher concentration in di abetic patients (average 9% versus 5% in healthy subjects), has an app roximately ten-fold higher oxygen affinity than non-glycosylated hemog lobin (HbA(0)). But the oxygen affinity in blood from diabetic patient s does not differ from that in healthy subjects. Thus, it was conclude d that 2,3-DPG, which lowers the oxygen affinity of hemoglobin by stab ilizing deoxyhemoglobin and which is increased in diabetic patients, c ompensates for the effect of HbA(1c). Therefore, oxygen release kineti cs of hemoglobin in diabetic patients (HbA(1c) = 9.3 +/- 0.3%) and hea lthy subjects (HbA(1c) = 5.2 +/- 0.3%) were compared and the influence of 2,3-DPG determined using the stopped flow technique. The oxygen di ssociation rate constant (k) of hemoglobin from the two groups did not differ (diabetic patients, 64.4 +/- 3.1 s(-1) and healthy subjects, 6 5.1 +/- 2.3 s(-1)). Addition of supraphysiological concentrations of 2 ,3-DPG produced physiologically insignificant changes in this paramete r. It is concluded that 2,3-DPG may not be the major factor compensati ng for the effect for HbA(1c) on oxygen release in diabetic patients.