ABSTRACT
This chapter reviews the state of knowledge regarding membrane transport processes for glutathione (GSH) and GSH S-conjugates in mammalian kidney. The isopeptide bond of the GSH molecule is a critical feature of the molecule that makes it resistant to degradation by the myriad proteases that exist in plasma. Rather, only the enzyme glutamyltransferase is capable of hydrolyzing this bond between the γ-carboxyl group of the glutamyl residue and the α-amino group of the cysteinyl residue. A characteristic feature of the renal proximal tubules is the presence of a large and diverse array of plasma membrane transporters. By functioning to deliver GSH to intracellular sites and counteract oxidative injury, basolateral membrane transport supports what one might call the "classic" functions of GSH as a reductant and nucleophile. Although analysis of kinetics in the basolateral membrane vesicles revealed only a single process, it is often difficult to discriminate among multiple transporters, particularly when the multiple carriers differ markedly in their kinetic parameters.
