Maintenance of glutathione content is isolated hepatocyctes

Abstract

During the standard procedure for the preparation of rat hepatocytes, about half of the cellular GSH (reduced glutathione) is lost. This loss is prevented by the addition of 0.1 mM EGTA [ethylene glycol tetraacetic acid] (but not EDTA) to the perfusion medium. On incubation with and without EGTA, isolated hepatocytes prepared in the presence of EGTA lose GSH. This loss is prevented by near-physiological concentrations of methionine or homocysteine, but not of cysteine. Cysteine, at concentrations above 0.2 mM, causes a loss of GSH, probably by non-enzymic formation of a mixed disulfide. Serine together with methionine or homocysteine increases GSH above the value in cells from starved rats in vivo. Cystathionine may be a cysteine donor in the synthesis of .gamma.-glutamylcysteine, the precursor of GSH.