The expression of CYP2B6, CYP2C9 and CYP3A4 genes: a tangle of networks of nuclear and steroid receptors

Biochim Biophys Acta. 2003 Feb 17;1619(3):243-53. doi: 10.1016/s0304-4165(02)00483-x.


Numerous chemicals increase the metabolic capability of organisms by their ability to activate genes encoding various xenochemical-metabolizing enzymes, such as cytochromes P450 (CYPs), transferases and transporters. For example, natural and synthetic glucocorticoids (agonists and antagonists) as well as other clinically important drugs induce the hepatic CYP2B, CYP2C and CYP3A subfamilies in man, and these inductions might lead to clinically important drug-drug interactions. Only recently, the key cellular receptors that mediate such inductions have been identified. They include nuclear receptors, such as the constitutive androstane receptor (CAR, NR1I3), the retinoid X receptor (RXR, NR2B1), the pregnane X receptor (PXR, NR1I2), and the vitamin D receptor (VDR, NR1I1) and steroid receptors such as the glucocorticoid receptor (GR, NR3C1). There is a wide promiscuity of these receptors in the induction of CYPs in response to xenobiotics. Indeed, this adaptive system appears now as a tangle of networks, where receptors share partners, ligands, DNA response elements and target genes. Moreover, they influence mutually their relative expression. This review is focused on these different pathways controlling human CYP2B6, CYP2C9 and CYP3A4 gene expression, and the cross-talk between these pathways.

Publication types

  • Review

MeSH terms

  • Animals
  • Aryl Hydrocarbon Hydroxylases / biosynthesis
  • Aryl Hydrocarbon Hydroxylases / genetics*
  • Colon / metabolism
  • Constitutive Androstane Receptor
  • Cytochrome P-450 CYP2B6
  • Cytochrome P-450 CYP2C9
  • Cytochrome P-450 CYP3A
  • Cytochrome P-450 Enzyme System / biosynthesis
  • Cytochrome P-450 Enzyme System / genetics*
  • Gene Expression Regulation, Enzymologic
  • Glucocorticoids / pharmacology
  • Humans
  • Intestine, Small / metabolism
  • Liver / metabolism
  • Oxidoreductases, N-Demethylating / biosynthesis
  • Oxidoreductases, N-Demethylating / genetics*
  • Pregnane X Receptor
  • Receptors, Calcitriol / metabolism
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Receptors, Glucocorticoid / metabolism
  • Receptors, Steroid / metabolism
  • Species Specificity
  • Transcription Factors / metabolism
  • Xenobiotics / pharmacology


  • Constitutive Androstane Receptor
  • Glucocorticoids
  • NR1I2 protein, human
  • NR1I3 protein, human
  • Pregnane X Receptor
  • Receptors, Calcitriol
  • Receptors, Cytoplasmic and Nuclear
  • Receptors, Glucocorticoid
  • Receptors, Steroid
  • Transcription Factors
  • Xenobiotics
  • Cytochrome P-450 Enzyme System
  • CYP2C9 protein, human
  • Cytochrome P-450 CYP2C9
  • Aryl Hydrocarbon Hydroxylases
  • CYP2B6 protein, human
  • CYP3A protein, human
  • Cytochrome P-450 CYP2B6
  • Cytochrome P-450 CYP3A
  • CYP3A4 protein, human
  • Oxidoreductases, N-Demethylating