Lower Expression of HNF4α and PGC1α Might Impair Rifampicin-mediated CYP3A4 Induction under Conditions Where PXR Is Overexpressed in Human Fetal Liver Cells
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- TAKEZAWA Takashi
- Department of Pharmacy, Shinshu University Hospital
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- MATSUNAGA Tamihide
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University
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- AIKAWA Kaori
- Department of Pharmacy, Shinshu University Hospital
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- NAKAMURA Katsunori
- Department of Pharmacy, Shinshu University Hospital
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- OHMORI Shigeru
- Department of Pharmacy, Shinshu University Hospital
Bibliographic Information
- Other Title
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- Lower expression of HNF4α and PGC1α might impair rifampicin-mediated CYP3A4 induction under conditions where PXR overexpressed in human fetal liver cells
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Abstract
Pregnane X receptor (PXR) mRNA was detected in HepG2 cells by RT-PCR, but not in human fetal liver (HFL) cells. CYP3A4 was induced by rifampicin (RIF), mifepristone (RU486), clotrimazole (CTZ), and dexamethasone (DEX) in HepG2 cells, while these PXR ligands with the exception of DEX did not induce CYP3A4 mRNA expression in HFL cells. Ad-PXR infection increased mRNA levels of PXR and CYP3A4 in both cells despite the absence of PXR ligands. Similar results were observed in reporter gene assays. However, in HFL cells, RIF-mediated CYP3A4 induction was insufficient compared with HepG2 cells, despite PXR overexpression. The expression levels of five coactivators (HNF4α, PGC1α, SRC1, CBP, and P300) related to CYP3A4 expression in HepG2, HFL cells, and human adult liver were analyzed by RT-PCR. Expression levels of HNF4α and PGC1α in HFL cells were downregulated to 20% of those in the human adult liver. On the other hand, the expression level of HNF4α in HepG2 cells was higher than that in HFL cells, although PGC1α expression level was almost the same as that in HFL cells. HNF4α mRNA expression level in HepG2 cells was 57% of that in human adult liver, and the level in HFL cells was 30% of that in HepG2 cells. These results suggested that lower expression of HNF4α and PGC1α may impair RIF-mediated CYP3A4 induction under conditions of PXR overexpression in HFL cells.<br>
Journal
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- Drug Metabolism and Pharmacokinetics
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Drug Metabolism and Pharmacokinetics 27 (4), 430-438, 2012
The Japanese Society for the Study of Xenobiotics