EFFECTS OF ETHANOL ADMINISTRATION ON CEREBRAL NONPROTEIN SULFHYDRYL CONTENT IN RATS EXPOSED TO STYRENE VAPOR

Glutathione (GSH) and other non-protein sulfhydryls (NPS) are known to protect cells from oxidative stress and from potentially toxic electr ophiles formed by biotransformation of xenobiotics. This study examine d the effect of a simultaneous administration of styrene and ethanol o n NPS content and lipid peroxidation in rat liver and brain. Hepatic c ytochrome P450 and cytochrome b(5) content, aniline hydroxylase and am inopyrine N-demethylase activities as well as the two major urinary me tabolites of styrene, mandelic and phenylglyoxylic acids were also mea sured. Groups of rats given ethanol for 3 weeks in a liquid diet were exposed, starting from the second week, to 326 ppm of styrene (6 h dai ly, 5 days a week, for 2 weeks). In control pair-fed animals, styrene produced about 30% depletion of brain NPS and 50% depletion of hepatic NPS. Subchronic ethanol treatment did not affect hepatic NPS levels, but caused 23% depletion of brain NPS. Concomitant administration of e thanol and styrene caused a NPS depletion in brain tissue in the order of 60%. These results suggest that in the rat, simultaneous exposure to ethanol and styrene may lead to considerable depletion of brain NPS . This effect is seen when both compounds are given on a subchronic ba sis, a situation which better resembles possible human exposure.