RT Journal Article SR Electronic T1 Comparative studies of the in vitro metabolism and covalent binding of 14C-benzene by liver slices and microsomal fraction of mouse, rat, and human. JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 20 OP 27 VO 18 IS 1 A1 J I Brodfuehrer A1 D E Chapman A1 T J Wilke A1 G Powis YR 1990 UL http://dmd.aspetjournals.org/content/18/1/20.abstract AB Metabolism of benzene by the liver has been suggested to play an important role in the hepatotoxicity of benzene. The role of the different benzene metabolites and the causes of species differences in benzene hepatotoxicity are, however, not known. The metabolism and covalent binding of 14C-benzene by liver microsomal fractions and liver slices from rat, mouse, and human subjects have been studied. Rat microsomal fraction formed phenol at a rate of 0.32 nmol/min/mg of protein; mouse microsomal fraction formed phenol at 0.64 nmol/min/mg and hydroquinone at 0.03 nmol/min/mg; and human microsomal fraction formed phenol at 0.46 nmol/min/mg and hydroquinone at 0.07 nmol/min/mg. Covalent binding of 14C-benzene metabolites to rat, mouse, and human liver microsomal protein was 29, 113, and 169 pmol/min/mg of protein, respectively. The rates of metabolite formation from benzene by liver slices in nmol/min/g of tissue were: rat, phenol 0.15, hydroquinone 0.26, and phenylsulfate 1.22; mouse: phenol 0.13, hydroquinone 0.29, phenylsulfate 1.37, and phenylglucuronide 1.34; and human: phenol 0.16, hydroquinone 0.27, phenylsulfate 0.83, and phenylglucuronide 0.52. trans,trans-Muconic acid formation was not detected with liver slices of any species. Covalent binding of 14C-benzene metabolites to rat, mouse, and human liver slices was 8.2, 79.7, and 27.3 pmol/min/g liver, respectively. There was no correlation between ascorbic acid levels in the human liver slices and covalent binding of 14C-benzene metabolites. The results show that phenol and hydroquinone found in extrahepatic tissues, including bone marrow, of animals exposed to benzene could originate from the liver. There was no evidence for the release of highly reactive benzene metabolites such as trans,trans-muconaldehyde or p-benzoquinone from liver cells.(ABSTRACT TRUNCATED AT 250 WORDS)