Reduction in cytochrome P-450 enzyme expression is associated with repression of CAR (constitutive androstane receptor) and PXR (pregnane X receptor) in mouse liver during the acute phase response

Biochem Biophys Res Commun. 2002 Apr 26;293(1):145-9. doi: 10.1016/S0006-291X(02)00196-1.


Expression of P-450 (Cyp) enzymes is reduced in liver during the acute phase response, contributing to the decrease in bile acid levels and drug metabolism during infection. Nuclear hormone receptors CAR and PXR are key transactivators of Cyp2b and Cyp3a genes, respectively. Injection of bacterial lipopolysaccharide (LPS) induced the expected reduction in Cyp2b10 and Cyp3a mRNA levels in mouse liver. These decreases were associated with a marked reduction in CAR and PXR mRNA levels within 4 h following treatment. LPS-induced CAR and PXR repression were dose-dependent and sustained for at least 16 h. LPS treatment also reversed the up-regulation of Cyp3a in mice pre-treated with PXR ligand RU486. In addition, we observed a concomitant decrease in RXR (retinoid X receptor) mRNA levels, the obligatory partner of both CAR and PXR for high affinity binding to DNA. These findings represent one possible molecular mechanism underlying sepsis-induced repression of Cyp enzymes.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Aryl Hydrocarbon Hydroxylases*
  • Cytochrome P-450 CYP3A
  • Cytochrome P-450 Enzyme System / drug effects
  • Cytochrome P-450 Enzyme System / genetics*
  • Escherichia coli
  • Female
  • Gene Expression Regulation, Enzymologic*
  • Lipopolysaccharides / pharmacology
  • Liver / enzymology*
  • Mice
  • Mice, Inbred C57BL
  • Models, Animal
  • Oxidoreductases, N-Demethylating / genetics
  • Pregnane X Receptor
  • Receptors, Cytoplasmic and Nuclear / genetics*
  • Receptors, Steroid / genetics*
  • Repressor Proteins / genetics
  • Trans-Activators / metabolism
  • Transcription Factors / genetics*


  • Lipopolysaccharides
  • Pregnane X Receptor
  • Receptors, Cytoplasmic and Nuclear
  • Receptors, Steroid
  • Repressor Proteins
  • Trans-Activators
  • Transcription Factors
  • constitutive androstane receptor
  • Cytochrome P-450 Enzyme System
  • Aryl Hydrocarbon Hydroxylases
  • Cytochrome P-450 CYP3A
  • Oxidoreductases, N-Demethylating