GLUTATHIONE DISULFIDE VARIABILITY IN NORMAL HUMAN BLOOD

A prevailing opinion is that glutathione disulfide (GSSG) levels in human blood are very low, but many studies have reported variable results. Therefore, our objective was to determine valid processing conditions for GSSG measurement and apply them to normal human blood samples. Reproducibility and stability of GSSG were demonstrated in acid extracts of a single sample of fresh whole blood by repetitive measurements during a 6-h period in which the %CVs were <10. In contrast, in normal subjects tested repeatedly over several years, GSSG values ranging from <2 to 166 nmol per 10(10) red blood cells were obtained and the overall %CV was 46. Lower GSSG values were obtained in hemolysates and ultrafiltrates. Thus, these results indicate that blood GSSG concentrations differ due to biological variation using optimal processing conditions. (C) 1994 Academic Press, Inc.