Studies in detoxication. 69. The metabolism of alkylbenzenes: n-propylbenzene and n-butylbenzene with further observations on ethylbenzene

Abstract

A study was made of the fate of ethylbenzene, n-propylbenzene and n-butylbenzene in the rabbit. About 60-70% of ethylbenzene undergoes alpha-oxidation to yield methylphenylcarbinol glucuronide and hippuric acid and 10-20% undergoes [beta]-oxidation to yield phenaceturic acid. About 50% of propylbenzene is excreted as the glucuronides of ethylphenylcarbinol and benzylmethylcarbinol, and about 15% as hippuric acid. The main precursor of hippuric acid appears to be benzylmethylcarbinol. About 50% of butylbenzene is excreted as the glucuronides of methyl-2-phenylethylcarbinol and phenylpropylcarbinol, and about 20% as phenaceturic acid. The precursor of phenaceturic acid appears to be methyl-2-phenylethylcarbinol; phenylpropylcarbinol is not a precursor. Derivatives of benzylethylcar-binol were not detected as metabolites of butylbenzene, and this carbinol is not a precursor of phenaceturic acid. The 3 alkylbenzenes were proved to undergo alpha-oxidation; propyl- and butyl-benzenes also undergo (w-l) -oxidation of the alkyl side chain. No direct evidence for the w-oxidation of propyl- and butyl-benzenes was obtained, but its occurrence cannot be ruled out. A method modified from Gaffney et al. (1954) was described for the determination of hippuric acid in urine.