| Literature DB >> 15120618 |
Tamihide Matsunaga1, Masataka Maruyama, Eri Harada, Yoshihiko Katsuyama, Nobuhiro Sugihara, Hirohiko Ise, Naoki Negishi, Uichi Ikeda, Shigeru Ohmori.
Abstract
CYP3A4 and CYP3A7 mRNA expression levels were markedly up-regulated by dexamethasone (DEX), but not by rifampicin (RIF). CYP3A5 mRNA level was not increased significantly by DEX, RIF, or phenobarbital. Testosterone 6beta-hydroxylase activity was induced to about 2-fold of control by DEX. However, concomitant treatment with RIF did not alter DEX-mediated induction of CYP3A mRNA expression and testosterone 6beta-hydroxylase activity. DEX-mediated induction of CYP3A mRNA was suppressed in a dose-dependent manner by RU486, a glucocorticoid receptor (GR) antagonist. At 5microM RU486, DEX-mediated induction of CYP3A4, CYP3A5, and CYP3A7 mRNA expression was inhibited almost completely. These results suggest that, in human fetal hepatocytes, PXR is not involved in DEX-mediated induction of CYP3A4 and CYP3A7, and that the induction is mediated directly by GR.Entities:
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Year: 2004 PMID： 15120618 DOI： 10.1016/j.bbrc.2004.04.041
Source DB: PubMed Journal: Biochem Biophys Res Commun ISSN： 0006-291X Impact factor: 3.575