CHARACTERIZATION OF 6-METHYL-1,3,8-TRICHLORODIBENZOFURAN (MCDF) AS A 2,3,7,8-TCDD ANTAGONIST IN MALE-RATS - INDUCTION OF MONOOXYGENASES Academic Article uri icon

abstract

  • Treatment of male Long Evans rats with doses of MCDF up to 200 mol/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 mol/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. 1989.

published proceedings

  • CHEMOSPHERE

author list (cited authors)

  • HARRIS, M., ZACHAREWSKI, T., ASTROFF, B., KAMPS, C., & SAFE, S.

citation count

  • 1

complete list of authors

  • HARRIS, M||ZACHAREWSKI, T||ASTROFF, B||KAMPS, C||SAFE, S

publication date

  • January 1989