title: Regulation of intestinal cytochrome P450 expression by hepatic cytochrome P450: possible involvement of fibroblast growth factor 15 and impact on systemic drug exposure.
abstract: Tissue-specific deletion of the gene for NADPH-cytochrome P450 (P450) reductase (CPR), the essential electron donor to all microsomal P450 enzymes, in either liver or intestine, leads to upregulation of many P450 genes in the tissue with the Cpr deletion. Here, by studying the liver-specific Cpr-null (LCN) mouse, we examined whether an interorgan regulatory pathway exists, such that a loss of hepatic CPR would cause compensatory changes in intestinal P450 expression and capacity for first-pass metabolism of oral drugs. We show for the first time that intestinal expression of CYP2B, 2C, and 3A proteins was increased in LCN mice by 2- to 3-fold compared with wild-type (WT) mice, accompanied by significant increases in small intestinal microsomal lovastatin-hydroxylase activity and systemic clearance of oral lovastatin (at 5 mg/kg). Additional studies showed that the hepatic Cpr deletion, which caused large decreases in bile acid (BA) levels in the liver, intestine, plasma, and intestinal content, led to drastic decreases in the mRNA levels of intestinal fibroblast growth factor 15 (FGF15), a target gene of the BA receptor farnesoid X receptor. Furthermore, treatment of mice with FGF19 (the human counterpart of mouse FGF15) abolished the difference between WT and LCN mice in small intestinal (SI) CYP3A levels at 6 hours after the treatment. Our findings reveal a previously unrecognized direct role of intestinal FGF15/19 in the regulation of SI P450 expression and may have profound implications for the prediction of drug exposure in patients with compromised hepatic P450 function.
authors.affiliation: Laboratory of Molecular Toxicology, Wadsworth Center, New York State Department of Health, and School of Public Health, State University of New York at Albany, Albany, New York.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu
authors.forename: Xinxin
authors.initials: X
authors.lastname: Ding
authors.forename: Cheng
authors.initials: C
authors.lastname: Fang
authors.forename: Qing-Yu
authors.initials: QY
authors.lastname: Zhang
mesh_terms: D000367:Age Factors; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005346:Fibroblast Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007421:Intestine, Small / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008148:Lovastatin / Q000493:pharmacokinetics*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008861:Microsomes / Q000201:enzymology; D009251:NADPH-Ferrihemoprotein Reductase / Q000235:genetics; D009928:Organ Specificity; D019821:Simvastatin / Q000493:pharmacokinetics*; D015854:Up-Regulation
chemical_list: D001647:Bile Acids and Salts; C117476:FGF19 protein, human; C108526:fibroblast growth factor 15, mouse; D005346:Fibroblast Growth Factors; D003577:Cytochrome P-450 Enzyme System; D008148:Lovastatin; D019821:Simvastatin; D051544:Cytochrome P-450 CYP3A; D009251:NADPH-Ferrihemoprotein Reductase