No abstract

Summary. Effect of intraperitoneal administration (5mmol/kg of body weight) of glucose-cysteine adduct (glc-cys) as a cysteine prodrug in rat tissues was studied. Cysteine levels in liver and kidney increased to 1.08 and 1.98~mol per g or ml, respectively, at 2h after the administration. GSH levels did not change substantially. However, when glc-cys was injected to rats treated with diethyl maleate, a GSH-depleting agent, the decreased GSH levels were restored rapidly. The recoveries in liver and kidney were 72% at lh and 66% at 2h, respectively, after glc-cys administration. Metabolism of glc-cys was assessed by urinary excretion of glc-cys, sulfate and taurine. Average excretion of glc-cys was 2.86mmol/kg/24h after glc-cys administration. Increased excretions of sulfate and taurine were 0.77 and 0.14 mmol/kg/24 h, respectively. Data show that, although glc-cys excretion was relatively rapid, glc-cys was effectively utilized for GSH synthesis in GSH-depleted tissues.

Summary.In situ perfusion of rat liver was performed with a medium containing glucose-cysteine adduct [2-(o-gluco-pentahydroxypentyl)-thiazolidine-4-carboxylic acid, glc-cys] and its effect on glutathione (GSH) and ATP levels and bile production was examined. The GSH content in the liver was maintained at the original level during perfusion with 1 mM glc-cys for 2 h, while it decreased significantly in the absence of glc-cys. After 4h of perfusion without glc-cys, ATP content and bile production decreased significantly besides the decrease in GSH content, but they were maintained at the original levels with glc-cys. When the perfusion was performed with the liver of rats injected with diethyl maleate (DEM), the GSH level, which was decreased to 6.0% of the control by DEM injection, was restored to 22.6% of the original level by perfusion with 2 mM glc-cys for 30 min. Data indicate that glccys is a cysteine prodrug with protective action on the liver.