title: Involvement of BCRP (ABCG2) in the biliary excretion of pitavastatin.
abstract: Pitavastatin, a novel potent 3-hydroxymethylglutaryl coenzyme A reductase inhibitor, is distributed selectively to the liver and excreted into bile in unchanged form in rats. We reported previously that the hepatic uptake is mainly mediated by organic anion transporting polypeptide (OATP) 1B1, whereas the biliary excretion mechanism remains to be clarified. In the present study, we investigated the role of breast cancer resistance protein (BCRP) in the biliary excretion of pitavastatin. The ATP-dependent uptake of pitavastatin by human and mouse BCRP-expressing membrane vesicles was significantly higher compared with that by control vesicles with Km values of 5.73 and 4.77 microM, respectively. The biliary excretion clearance of pitavastatin in Bcrp1-/- mice was decreased to one-tenth of that in control mice. The biliary excretion of pitavastatin was unchanged between control and Eisai hyperbilirubinemic rats, indicating a minor contribution of multidrug resistance-associated protein (Mrp) 2. This observation differs radically from that for a more hydrophilic statin, pravastatin, of which biliary excretion is largely mediated by Mrp2. These data suggest that the biliary clearance of pitavastatin can be largely accounted for by BCRP in mice. In the case of humans, transcellular transport of pitavastatin was determined in the Madin-Darby canine kidney II cells expressing OATP1B1 and human canalicular efflux transporters. A significant basal-to-apical transport of pitavastatin was observed in OATP1B1/MDR1 and OATP1B1/MRP2 double transfectants as well as OATP1B1/BCRP double transfectants, implying the involvement of multiple transporters in the biliary excretion of pitavastatin in humans. This is in contrast to a previous belief that the biliary excretion of statins is mediated mainly by MRP2.
authors.affiliation: Department of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Hirano
authors.forename: Kazuya
authors.initials: K
authors.lastname: Maeda
authors.forename: Soichiro
authors.initials: S
authors.lastname: Matsushima
authors.forename: Yoshitane
authors.initials: Y
authors.lastname: Nozaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kusuhara
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sugiyama
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000502:physiology*; D000818:Animals; D001646:Bile / Q000378:metabolism; D002460:Cell Line; D004285:Dogs; D004970:Estrone / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D051379:Mice; D000089762:Multidrug Resistance-Associated Protein 2; D009363:Neoplasm Proteins / Q000502:physiology*; D011804:Quinolines / Q000097:blood / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C000715087:ABCC2 protein, human; C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000089762:Multidrug Resistance-Associated Protein 2; D009363:Neoplasm Proteins; D011804:Quinolines; D004970:Estrone; C108475:pitavastatin; C017296:estrone sulfate