A study was performed to evaluate an effect of toluene or ethanol pretreatment on the toluene metabolism.
A slight liver damage in rats was induced by administration of 0.2 ㎖ of toluene or 0.2 ㎖ of 50% ethanol per 100 g of body weight intraperitoneally every other day for four weeks except the last day before sacrifice. One day before sacrifice, toluene was administered to rats pretreated ethanol or toluene and the control. Rats were sacrificed at the lst, the 2nd, the 3rd and the 4th week after the first administration of xenobiotics mentioned above.
Based on the histopathological findings, liver weight per body weight, serum alanine aminotransferase and hepatic glutathione content, toluene- or ethanol-pretreated groups showed the reversible liver injury. By the treatment of one dose of toluene, the contents of hippuric acid in urine was higher in the group pretreated with toluene or ethanol than control.
The contents of cytochrome P-450, benzylalcohol dehydrogenase and benzaldehyde dehydrogenase activities were generally more increased in toluene- or ethanol-pretreated rats than control.
K_m values of the benzylalcohol dehydrogenase in pooled liver samples from toluene- and ethanol-pretreated groups were similar each other. V_(max) values of toluene- or ethanol-pretreated group was higher than control.
In conclusion, the toluene metabolism is accelerated in rats pretreated with toluene or ethanol.
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