The effect of combined exposures to ethanol and xylene on rat hepatic microsomal monooxygenase activities.
Studies on rats treated for 8 months with ethanol (10% solution in drinking water) and simultaneously exposed to xylene vapour (12,000 mg/m3, 5 hr daily) for the last 9 days revealed that the chemicals exert additive stimulatory effect on hepatic microsomal monooxygenase: the activity of aniline p-hydroxylase increased by 380%, microsomal ethanol oxidizing system by 92%, NADPH-cyt. c reductase by 30% and the level of cytochrome P-450 by 70%. The changes were accompanied by a marked proliferation of smooth endoplasmic reticulum (a subcellular site of cytochrome P-450 monooxygenases in the hepatocytes) and an increased NADPH-Fe2+- and ascorbate-Fe2+-driven lipid peroxidation in microsomal membranes--a potential toxic mechanism. Interaction of ethanol and xylene with cytochrome P-450 monooxygenases may enhance metabolic capacity of the liver and in consequence modify biological/toxic effects of occupational exposure to solvents in the case of alcohol abuse.
Wiśniewska-Knypl
J M
JM
Department of Biochemistry, Nofer's Institute of Occupational Medicine, Lodz, Poland.
Wrońska-Nofer
T
T
Jajte
J
J
Jedlińska
U
U
D000818:Animals; D004357:Drug Synergism; D000431:Ethanol / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology* / Q000648:ultrastructure; D008862:Microsomes, Liver / Q000378:metabolism* / Q000648:ultrastructure; D010105:Oxygenases / Q000378:metabolism*; D051381:Rats; D014992:Xylenes / Q000494:pharmacology*
D014992:Xylenes; D000431:Ethanol; D010105:Oxygenases