Human kidney proximal tubules are the main source of plasma glutathione peroxidase

Glutathione peroxidase (GPX) activities and selenium concentrations in the plasma of patients suffering from renal failure on dialysis and nephrectomized patients before and after transplantation were measured to evaluate the principal source of plasma GPX. Northern hybridization analysis showed that the ratio of extracellular GPX to cellular GPX was maximum in the kidney. Extracellular GPX transcripts were found in proximal tubular epithelial cells and parietal epithelial cells of Bowman's capsule.