PCB isomers and congeners: Induction of aryl hydrocarbon hydroxylase and ethoxyresorufin O-deethylase enzyme activities in rat hepatoma cells

T. Sawyer, S. Safe

Research output: Contribution to journalArticle

150 Scopus citations

Abstract

The effects of structure on the activity of 15 polychlorinated biphenyl (PCB) isomers and congeners as inducers of cytochrome P-448-dependent monooxygenases in rat hepatoma cell cultures was investigated. All the PCBs which have previously been classified as aryl hydrocarbon hydroxylase (AHH) inducers in the immature male Wistar rat also induced benzo[a]pyrene hydroxylase and ethoxyresorufin (ER) O-deethylase activity in the rat hepatoma H-4-II-E cells. The relative activities of the compounds were evaluated by comparing the doses required to half-maximally induce the two enzyme activities. The most potent PCB inducer, 3,3',4,4',5-pentachlorobiphenyl, exhibited molar EC50 values of 2.48 · 10-10 and 2.40 · 10-10 for the induction of ER O-deethylase and benzo[a]pyrene hydroxylase enzyme activities, respectively. These values were only 3- to 4-fold lower than the data obtained for the highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The relative activities of the PCB congeners as inducers of cytochrome P-448-dependent monooxygenase in vitro were similar to their potencies as microsomal enzyme inducers in the immature male rat.

Original languageEnglish (US)
Pages (from-to)87-93
Number of pages7
JournalToxicology Letters
Volume13
Issue number1-2
DOIs
StatePublished - Sep 1982

ASJC Scopus subject areas

  • Toxicology

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