Modulation of endothelial GSH concentrations: effect of exogenous GSH and GSH monoethyl

1029-1034, 1989.-We studied the effects of exogenous gluta-thione (GSH) and GSH monoethyl ester (GSH-MEE) on the enhancement of endothelial GSH concentrations. The prepa-ration of GSH-MEE used contained 91 % GSH-MEE,-9% GSH diethyl ester (GSH-DEE) and a trace amount of GSH. Both GSH and GSH-MEE markedly stimulated the intracel-lular concentrations of GSH in endothelial cells. GSH-MEE was more potent than GSH. The enhancement of endothelial GSH concentration by exogenous GSH was completely inhib-ited by buthionine sulfoximine (BSO), a potent inhibitor of y-glutamylcysteine synthase, or acivicin (AT-125), an inhibitor of y-glutamyl transpeptidase, suggesting that it was due to the extracellular breakdown and subsequent intracellular resyn-thesis of GSH. In contrast, the effect of GSH-MEE was largely resistant to BSO and acivicin, suggesting that it was primaril