OXYGEN RELEASE KINETICS IN HEALTHY-SUBJECTS AND DIABETIC-PATIENTS .2.EFFECTS OF HBCO

Glycosylated hemoglobin (HbA(1c)) and carboxyhemoglobin (HbCO) are ele vated in diabetic smokers. Both increase the oxygen affinity of hemogl obin and lower the velocity of oxygen release. We have, therefore, mea sured the influence of HbCO on the oxygen dissociation kinetics of hem oglobin in blood from healthy subjects (HbA(1c) = 5.3 +/- 0.3%, n = 12 ) and diabetic patients (HbA(1c) = 8.4 +/- 1.6%, n = 12) using the sto pped flow technique. In addition, the effect of 2,3-DPG on the oxygen dissociation rate of hemoglobin containing high concentrations of HbCO was examined. Neither statistically nor clinically significant differ ences in the oxygen dissociation rate between blood from healthy subje cts and diabetic patients were found. Increasing the HbCO concentratio n up to 20% of total hemoglobin produced an approximately 20% decrease (p < 0.001) in the dissociation rate constant in blood samples from b oth groups of subjects. Addition of 20 mmol 2,3-DPG per 10 mmol hemogl obin had little effect on the magnitude of these changes. It is conclu ded that HbCO values similar to those present in smokers cause a signi ficant decrease of oxygen release in healthy subjects and diabetic pat ients. Elevated HbA(1c) concentrations do not potentiate the effects o f HbCO on oxygen release in either group of subjects.