title: Determination of selenium concentration and glutathione peroxidase activity in plasma and erythrocytes.
abstract: We determined selenium concentrations and activities of the selenoenzyme, glutathione peroxidase (EC 1.11.1.9), in the plasma and erythrocytes of 38 apparently healthy women. We determined selenium concentrations directly by polarized Zeeman-effect flameless atomic absorption spectroscopy. Within-run precision studies for the assays gave CVs of 5.6% for a mean erythrocyte selenium concentration of 149.9 (SD 8.3) microgram/L (n = 10) and 6.4% for a mean plasma selenium concentration of 97.3 (SD 6.2) microgram/L (n = 12). For the women, mean selenium concentrations were 141.4 (SD 14.3) microgram/L of erythrocytes [0.49 (SD 0.07) microgram/g of hemoglobin and 96.3 (SD 14.2) microgram/L of plasma. Glutathione peroxidase activities were measured by a modification of the method of Paglia and Valentine (J. Lab. Clin. Med. 70: 158--169, 1967). Within-run precision studies for the glutathione peroxidase assays gave CVs of 12.8% for mean erythrocyte glutathione peroxidase activity of 77.2 (SD 9.9) U/g of hemoglobin (n = 13), and 8.1% for mean plasma activity of 312.5 (SD 25.2) U/L (n = 11). Mean enzyme activity was 78.7 (SD 12.9) U/g of hemoglobin for erythrocytes and 424 (SD 40) U/L for plasma. Erythrocyte selenium concentrations and glutathione peroxidase activities were positively, but poorly, correlated (r = 0.41, p less than 0.01).
mesh_terms: D000328:Adult; D000368:Aged; D003276:Contraceptives, Oral / Q000494:pharmacology; D004912:Erythrocytes / Q000032:analysis* / Q000201:enzymology; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D010544:Peroxidases / Q000097:blood*; D010949:Plasma / Q000032:analysis / Q000201:enzymology; D044469:Racial Groups; D012643:Selenium / Q000097:blood*; D013050:Spectrometry, Fluorescence; D013054:Spectrophotometry, Atomic / Q000379:methods
chemical_list: D003276:Contraceptives, Oral; D010544:Peroxidases; D005979:Glutathione Peroxidase; D012643:Selenium