Characterization of 6-methyl-1,3,8-trichlorodibenzofuran (MCDF) as a 2,3,7,8-TCDD antagonist in male rats: induction of monooxygenases

M. Harris, T. Zacharewski, B. Astroff, C. Kamps, S. Safe

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Treatment of male Long Evans rats with doses of MCDF up to 200 μmol/kg did not significantly induce hepatic microsomal aryl hydrocarbon hydroxylase (AHH) or ethoxyresorufin O-deethylase (EROD) activities, whereas administration of 2,3,7,8-TCDD (16 nmol/kg) caused up to a 10 to 40-fold induction of these enzymes. Cotreatment of the rats with 2,3,7,8-TCDD (16 nmol/kg) and MCDF (50 μmol/kg) resulted in the inhibition of the monooxygenase enzyme induction response over a 72 hour period. Treatment of the animals with 2,3,7,8-TCDD alone caused an initial decrease in the concentration of the cytosolic Ah receptor followed by an increase of these levels (∼2 times higher than in control rats) after 72 hours. In contrast, MCDF treatment did not alter hepatic cytosolic Ah receptor levels and in the cotreatment studies (MCDF + TCDD), the effects of 2,3,7,8-TCDD on receptor levels was inhibited. Using [3H]-2,3,7,8-TCDD (+ MCDF), the time-course accumulation of nuclear [3H]-2,3,7,8-TCDD-receptor complexes was also investigated. Surprisingly, MCDF did not decrease occupied nuclear 2,3,7,8-TCDD-Ah receptor levels.

Original languageEnglish (US)
Pages (from-to)769-772
Number of pages4
JournalChemosphere
Volume19
Issue number1-6
DOIs
StatePublished - 1989

Keywords

  • 6-Methyl-1,3,8-trichlorodibenzofuran
  • TCDD antagonisst

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

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