ABSTRACT
The rapid turnover of glutathione involves its secretion and extracellular catabolism which occurs primarily within the kidney. 1 The renal catabolism of glutathione is initiated by γ-glutamyltranspeptidase, an ectoenzyme that is associated with both the apical and the basolateral plasma membranes of the proximal tubular epithelial cells. The turnover of glutathione within these cells also occurs very rapidly. This process apparently involves the selective secretion of glutathione through the apical plasma membrane. Various studies using single-pass perfusion 2 , 3 and renal clearance techniques 4 have attempted to characterize and to quantitate the individual processes of apical and peritubular catabolism. In addition, unique transport systems for glutathione and γ-glutamyl peptides have been characterized using isolated renal brush border 5 and basolateral 6 membrane vesicles. Based upon these data, a model has been formulated which can account for the renal handling of glutathione. 7
