Kinetic analysis in single, intact cells by microspectrophotometry: evidence for two populations of erythrocytes in an individual heterozygous for glucose-6-phosphate dehydrogenase deficiency.
A microspectrophotometric technique was used to measure the kinetics of methemoglobin reduction in intact, unaltered human erythrocytes. Reduction was catalyzed by endogenous NADPH-methemoglobin reductase in the presence of Nile Blue. The technique was applied to the study of erythrocytes from a female donor with decreased glucose-6-phosphate dehydrogenase (G-6-PD) activity. The individual was shown to be heterozygous for deficiency of G-6-PD. The kinetic study revealed two distinct populations of erythrocytes that were nearly equal in number. One cell population showed reduction rates between 0 and 25% of normal, whereas the second cell population displayed rates within the range seen for normal cells. Single-cell indices of cell size, cell hemoglobin content, and ratio of cell hemoglobin to cell size did not correlate with single-cell reduction rates and were not significantly different between the two populations. These results provide quantitative support for the X-inactivation hypothesis in G-6-PD deficiency.
D000328:Adult; D004912:Erythrocytes / Q000145:classification* / Q000378:metabolism; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000097:blood; D005955:Glucosephosphate Dehydrogenase Deficiency / Q000097:blood / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D007700:Kinetics; D008297:Male; D008706:Methemoglobin / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D013053:Spectrophotometry
D009249:NADP; D008706:Methemoglobin; D005954:Glucosephosphate Dehydrogenase