Induction of 7-ethoxyresorufin-O-deethylase (EROD) activity in mice foetuses by the PCB-congener 3,3',4,4'-tetrachlorobiphenyl

Xenobiotica. 1993 Feb;23(2):107-14. doi: 10.3109/00498259309059366.


1. 3,3',4,4'-Tetrachlorobiphenyl (TCB) induces liver microsomal 7-ethoxyresorufin-O-deethylase (EROD) activity, and this P450 isoform, i.e. CYP 1, is involved in the metabolism of TCB. 2. TCB administered i.p. to pregnant mice (5-25 mg/kg) induced foetal as well as maternal hepatic EROD activity; in all cases the maternal induced activity was higher than the foetal activity. EROD activity of TCB-induced foetuses increased with developmental age, but decreased with the length of time after treatment. 3. Strain differences were seen; in control mice and TCB-treated dams NMRI > C57BL in EROD activity, but in transplacentally TCB-treated foetuses, C57BL > NMRI. EROD activity in non-pregnant control C57BL mice was higher than in pregnant ones, whereas no activity was seen in control foetuses. 4. Results indicate that TCB at a certain dose can induce foetal metabolism, but that earlier observed foetal accumulation at lower TCB doses is probably a consequence of transplacental transport of maternally-produced metabolites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cytochrome P-450 CYP1A1
  • Cytochrome P-450 Enzyme System / biosynthesis*
  • Cytochrome P-450 Enzyme System / metabolism
  • Dose-Response Relationship, Drug
  • Enzyme Induction / drug effects
  • Female
  • Fetus / drug effects*
  • Fetus / enzymology
  • Mice
  • Mice, Inbred C57BL
  • Microsomes, Liver / drug effects
  • Microsomes, Liver / enzymology
  • Oxidoreductases / biosynthesis*
  • Oxidoreductases / metabolism
  • Polychlorinated Biphenyls / toxicity*
  • Pregnancy
  • Time Factors


  • Cytochrome P-450 Enzyme System
  • Polychlorinated Biphenyls
  • Oxidoreductases
  • Cytochrome P-450 CYP1A1
  • 3,4,3',4'-tetrachlorobiphenyl