PLASMA GLUTATHIONE-PEROXIDASE DEFICIENCY CAUSED BY RENAL DYSFUNCTION

Glutathione peroxidase (GPx) activity was determined in the plasma of 118 healthy persons, 18 nondialyzed patients with chronic renal failur e (CRF), 20 patients on maintenance hemodialysis (HD), and 58 patients on continuous ambulatory peritoneal dialysis (CAPD). Serum creatinine levels in the nondialyzed CRF patients revealed a highly significant negative correlation (r = -0.71, p < 0.001) with plasma GPx activity. Immunoblot analysis revealed that the plasma (extracellular) GPx prote in was reduced or undetectable in patients with low plasma GPx activit y. Plasma GPx activities in the HD and CAPD patients were reduced to 4 4 and 23% (female), and to 70 and 45% (male) of the sex-matched contro l values, respectively. In contrast, erythrocyte (cellular) GPx activi ty was not decreased in the nondialyzed CRF patients and the dialyzed patients. Plasma selenium concentrations were within the normal range in these patient groups. These results indicate that the plasma GPx ac tivity largely depends on renal function.