Protective effect of S-(1,2-dicarboxyethyl)glutathione, an intrinsic tripeptide in liver, heart and lens, and its esters on acetaminophen-induced hepatotoxicity in rats.

The administration of acetaminophen (APAP, 500 mg/kg, i.p.) produced liver necrosis and increased aspartate aminotransaminase (AST) activity in serum. The pretreatment of S-(1,2-diethoxycarbonyl)glutathione isopropyl ester (DCE-Et-GS iPr, 0.5 mmol/kg, p.o.) prevented hepatic necrosis and the elevation of serum AST activity by 99.9%. DCE-Et-GS iPr inhibited APAP-induced hepatotoxicity much more strongly than reduced glutathione (GSH), DCE-GS and other esters of DCE-GS. To clarify this protective effect, the hepatic GSH concentration was determined 2h after APAP administration. It was found that the DCE-Et-GS iPr administration significantly inhibited the GSH depletion caused by APAP, suggesting that the protective effect of DCE-Et-GS iPr on APAP-induced hepatotoxicity was due, at least in part, to the retention of hepatic GSH level.