S-acetyl- and S-phenylacetyl-glutathione as glutathione precursors in rat plasma and tissue preparations.

S-acetyl- and S-phenylacetyl-glutathione derivatives were synthesized by using a new procedure. The derivatives were incubated with rat plasma and red blood cells, and also with cytosol from rat liver, kidney and heart, or tissue slices from rat heart, kidney and liver. A limited hydrolysis of the compounds occurs in plasma, whereas hydrolysis occurs to a larger extent in tissue cytosols. Both purified and crude gamma-glutamyl-transpeptidase from different sources recognized the S-acetyl- and S-phenylacetyl derivatives as substrates. Intracellular glutathione increases after incubating the derivatives with red blood cells. A potential role of S-acetyl- and S-phenylacetyl-glutathione in replenishing cells with exogenous glutathione is envisaged.