Characterization of human fetal hepatic cytochrome P-450-associated 7-ethoxyresorufin O-deethylase and aryl hydrocarbon hydroxylase activities by monoclonal antibodies

Dev Pharmacol Ther. 1987;10(2):125-32. doi: 10.1159/000457737.


Two cytochrome P-450-dependent enzyme activities, 7-ethoxyresorufin O-deethylase (ERDE) and aryl hydrocarbon hydroxylase (AHH) were measured in liver microsomes from 7 human fetuses. Monoclonal antibodies (MAb) to a 3-methylcholanthrene-induced (MAb 1-7-1) and a phenobarbital-induced (MAb 2-66-3) rat hepatic cytochrome P-450 were used to measure the contribution of the MAb-defined, epitope-specific cytochromes P-450 to the total reaction measured for the above activities. MAb 1-7-1 inhibited fetal hepatic ERDE activity to a variable extent (from 0 to 100%, 34 in average), but had only negligible effects on AHH activity (mean inhibition 9%). The contribution of induction by cigarette smoking to the variability of ERDE inhibition by MAb 1-7-1 remained unclear. MAb 2-66-3 inhibited ERDE activity by 18% and AHH activity by 12%. In comparisons with earlier studies on adult liver and placental microsomes, the present results with fetal liver suggest that there are differences in cytochrome P-450-associated ERDE and AHH activities between these tissues, which might be due to different tissue-specific isoenzyme patterns.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal*
  • Aryl Hydrocarbon Hydroxylases / analysis*
  • Cytochrome P-450 CYP1A1
  • Cytochrome P-450 Enzyme System / analysis*
  • Female
  • Fetus / metabolism*
  • Humans
  • Liver / embryology
  • Liver / enzymology*
  • Microsomes, Liver / enzymology
  • Oxidoreductases / analysis*
  • Placenta / enzymology
  • Pregnancy


  • Antibodies, Monoclonal
  • Cytochrome P-450 Enzyme System
  • Oxidoreductases
  • Aryl Hydrocarbon Hydroxylases
  • Cytochrome P-450 CYP1A1