Species-specific activation of phenacetin into bacterial mutagens by hamster liver enzymes and identification of n-hydroxyphenacetin o-glucuronide as a promutagen in the urine

Anne Marie Camus, Marlin Friesen, Helmut Bartsch

Research output: Contribution to journalArticlepeer-review

Abstract

Phenacetin was mutagenic in Salmonella typhimurium TA100 in plate assays when liver fractions from Aroclor-treated hamsters, but not rats, were used. Its known or putative metabolites were synthesized; of these, N-hydroxyphenacetin and N-acetoxyphenacetin were found to be mutagenic in liquid and plate assays, both requiring activation by liver fractions from Aroclor-treated hamsters. 2-Hydroxyphenacetin and 2-acetoxyphenacetin were nonmutagenic. N-Hydroxyphenetidine (the deacetylated metabolite of phenacetin) and p-nitrosophenetole were the only products that were found to be mutagenic per se when assayed under N2in either Salmonella TA100 and TA100 NR (nitroreductase-deficient) strains. Phenacetin was administered to male BDVI rats and Syrian golden hamsters, and its urinary metabolites were deconju-gated with β-glucuronidase:arylsulfatase. After reactivation by hamster liver fractions, mutagenicity was demonstrated in S. typhimurium TA100 with urine from phenacetin-treated hamsters, but not with that from rats. After treatment with deconjugating enzymes, N-hydroxyphenacetin was isolated from hamster urine by high-performance liquid chromatography and identified by mass spectral analysis. The data support the conclusions that (a) N-hydroxyphenacetin is a proximate mutagenic metabolite of phenacetin which, after N-deacetylation is responsible for the mutagenicity observed in vitro and in the urine of hamsters and (b) the higher yield of N-hydroxyphenacetin that is formed in the liver of hamsters as compared to rats explains the pronounced species-specific activation of phenacetin into bacterial mutagens.

Original languageEnglish (US)
Pages (from-to)3201-3208
Number of pages8
JournalCancer Research
Volume42
Issue number8
StatePublished - Aug 1 1982

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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