Enhancement of cysteine catabolism into taurine impacts glutathione homeostasis in rats challenged with ethanol.

We determined the alterations in metabolic conversion of cysteine into glutathione and taurine in liver of rats treated with ethanol acutely. Ethanol treatment reduced cysteine as well as glutathione levels in liver for 24 h. However, cysteine dioxygenase was up-regulated rapidly, and hypotaurine/taurine levels were significantly higher than those found in the saline-treated rats. It is therefore suggested that enhancement of cysteine catabolism into taurine contributes to the depletion of hepatic glutathione, which could exacerbate the ethanol-induced oxidative liver injury.