PT  - JOURNAL ARTICLE
AU  - Luo, Gang
AU  - Cunningham, Mark
AU  - Kim, Sean
AU  - Burn, Tim
AU  - Lin, Jianrong
AU  - Sinz, Michael
AU  - Hamilton, Geraldine
AU  - Rizzo, Christopher
AU  - Jolley, Summer
AU  - Gilbert, Darryl
AU  - Downey, April
AU  - Mudra, Daniel
AU  - Graham, Richard
AU  - Carroll, Kathy
AU  - Xie, Jindong
AU  - Madan, Ajay
AU  - Parkinson, Andrew
AU  - Christ, Dave
AU  - Selling, Bernard
AU  - LeCluyse, Edward
AU  - Gan, Liang-Shang
TI  - CYP3A4 Induction by Drugs: Correlation between a Pregnane X Receptor Reporter Gene Assay and CYP3A4 Expression in Human Hepatocytes
AID  - 10.1124/dmd.30.7.795
DP  - 2002 Jul 01
TA  - Drug Metabolism and Disposition
PG  - 795--804
VI  - 30
IP  - 7
4099  - http://dmd.aspetjournals.org/content/30/7/795.short
4100  - http://dmd.aspetjournals.org/content/30/7/795.full
SO  - Drug Metab Dispos2002 Jul 01; 30
AB  - Induction of cytochrome P450 3A4 (CYP3A4) is determined typically by employing primary culture of human hepatocytes and measuring CYP3A4 mRNA, protein and microsomal activity. Recently a pregnane X receptor (PXR) reporter gene assay was established to screen CYP3A4 inducers. To evaluate results from the PXR reporter gene assay with those from the aforementioned conventional assays, 14 drugs were evaluated for their ability to induce CYP3A4 and activate PXR. Sandwiched primary cultures of human hepatocytes from six donors were used and CYP3A4 activity was assessed by measuring microsomal testosterone 6β-hydroxylase activity. Hepatic CYP3A4 mRNA and protein levels were also analyzed using branched DNA technology/Northern blotting and Western blotting, respectively. In general, PXR activation correlated with the induction potential observed in human hepatocyte cultures. Clotrimazole, phenobarbital, rifampin, and sulfinpyrazone highly activated PXR and increased CYP3A4 activity; carbamazepine, dexamethasone, dexamethasone-t-butylacetate, phenytoin, sulfadimidine, and taxol weakly activated PXR and induced CYP3A4 activity, and methotrexate and probenecid showed no marked activation in either system. Ritonavir and troleandomycin showed marked PXR activation but no increase (in the case of troleandomycin) or a significant decrease (in the case of ritonavir) in microsomal CYP3A4 activity. It is concluded that the PXR reporter gene assay is a reliable and complementary method to assess the CYP3A4 induction potential of drugs and other xenobiotics. The American Society for Pharmacology and Experimental Therapeutics