Interspecies differences in glutathione-dependent detoxication of hydroperoxides in short-term cultures of hepatocytes

Abstract

Whether the glutathione-dependent detoxication pathway of hydroperoxides is functionally expressed in vitro is not known. The major components of the system were studied in freshly isolated hepatocytes and their short-term primary monolayer cultures. The hepatocytes were derived from human organ donors, Sprague-Dawley rats, beagle dogs and cynomolgus monkeys. Species differences exist in the intracellular (reduced) glutathione (GSH) content of freshly isolated hepatocytes. In particular, the GSH content of rat hepatocytes is small in comparison with that in human cells. Monkey hepatocytes displayed the highest levels, followed by human, dog and rat cells. After 24 hr in culture, the GSH content of the hepatocytes increased, in all the species studied. With respect to the glutathione reductase activity, freshly isolated human hepatocytes showed a level that was half that found for monkeys and rats and was approximately 1.5-fold of the activity measured in dog hepatocytes. These differences were maintained during short-term culture. When glutathione peroxidase activities were measured, using hydrogen peroxide or tertiary butylhydroperoxide as substrates, the highest values were seen for rat hepatocytes followed by human, monkey and dog cells. Thus, it is clear that hepatocytes of different species have different GSH-dependent detoxication capacities.