Alcohol and sulphate intermediates in the metabolism of toluene and xylenes to mercapturic acids.
The involvement of sequential side-chain oxidation, sulphation and glutathione conjugation in the formation of mercapturic acids from toluene and xylenes was investigated. It was found that not only aralkanes but also aralkyl alcohols were excreted as mercapturic acids in the rat. The extent of mercapturic acid excretion varied over a more than 20-fold range. Inhibition of ADH caused an increase and inhibition of sulphotransferase a decrease in the urinary excretion of thio compounds after administration of toluene, benzyl alcohol, o-xylene and o-methylbenzyl alcohol to rats. The position of the methyl groups attached to the aromatic nucleus affects the metabolism of aromatic hydrocarbons considerably. Factors that are involved in the high yield of mercapturic acids after administration of o-xylene as compared to m- and p-xylene, include the relatively low apparent affinity of o-methylbenzyl alcohol for cytosolic ADH, the relatively high apparent affinity of o-methylbenzyl alcohol for cytosolic sulphotransferase, and the high electrophilic reactivity of the o-methylbenzyl sulphate.
D000111:Acetylcysteine / Q000378:metabolism*; D000426:Alcohol Dehydrogenase; D000429:Alcohol Oxidoreductases / Q000032:analysis; D000438:Alcohols / Q000378:metabolism*; D000818:Animals; D003404:Creatinine / Q000652:urine; D003600:Cytosol / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013431:Sulfates / Q000378:metabolism*; D014050:Toluene / Q000378:metabolism*; D014992:Xylenes / Q000378:metabolism*
D000438:Alcohols; D013431:Sulfates; D014992:Xylenes; D014050:Toluene; D003404:Creatinine; D000429:Alcohol Oxidoreductases; D000426:Alcohol Dehydrogenase; D005978:Glutathione; D000111:Acetylcysteine