GLYCINE FACILITATES GAMMA-GLUTAMYLCYSTEINYLETHYL ESTER-MEDIATED INCREASE IN LIVER GLUTATHIONE LEVEL

gamma-Glutamylcysteinylethyl ester (gamma-GCE) increases reduced gluta thione (GSH) levels in GSH-depleted rat hepatocytes. Because glycine, a constituent of GSH, exists at 0.3 to 0.4 mM in rat plasma, we examin ed the influence of glycine added to the medium on the action of gamma -GCE to increase GSH levels in the rat hepatocytes. Glycine (0.2-0.8 m M) dose-dependently enhanced gamma-GCE-mediated increase in intracellu lar GSH levels with an increase in intracellular gamma-GCE levels. The se results indicate that exogenous glycine facilitates gamma-GCE-media ted increase in intracellular GSH levels in rat hepatocytes possibly b y enhancing the uptake of gamma-GCE into the cells. (C) 1997 Elsevier Science B.V.