title: Predominant contribution of OATP1B3 to the hepatic uptake of telmisartan, an angiotensin II receptor antagonist, in humans.
abstract: Telmisartan, a nonpeptide angiotensin II receptor antagonist, is selectively distributed to liver. In the present study, we have characterized the contribution of organic anion transporting polypeptide (OATP) isoforms to the hepatic uptake of telmisartan by isolated rat hepatocytes, human cryopreserved hepatocytes, and human transporter-expressing cells. Because it is difficult to evaluate the transport activity of telmisartan because of its extensive adsorption to cells and culture materials, we performed the uptake study in the presence of human serum albumin. The saturable uptake of telmisartan into isolated rat hepatocytes took place in a Na(+)-independent manner and was inhibited by pravastatin, taurocholate, and digoxin, which are Oatp substrates and inhibitors, but not by organic cation, tetraethylammonium, indicating the involvement of Oatp isoforms in its uptake into rat hepatocytes. To identify which human OATP transporters are important for the hepatic uptake of telmisartan, the uptake assay was carried out using OATP1B1- and OATP1B3-expressing human embryonic kidney 293 cells and cryopreserved human hepatocytes. The uptake of telmisartan by OATP1B3-expressing cells was saturable (K(m) = 0.81 microM) and significantly higher than that by vector-transfected cells. In contrast, no significant uptake was observed in OATP1B1-expressing cells. We also observed the saturable uptake of telmisartan by human hepatocytes. Thirty micromolar estrone-3-sulfate, which can selectively inhibit OATP1B1-mediated uptake compared with OATP1B3, did not inhibit the uptake of telmisartan in human hepatocytes, whereas it could inhibit the uptake of estradiol 17beta-d-glucuronide mediated by OATP1B1. These results suggest that OATP1B3 is predominantly involved in the hepatic uptake of telmisartan in humans.
authors.affiliation: Department of Pharmacokinetics and Non-Clinical Safety, Kawanishi Pharma Research Institute, Nippon Boehringer Ingelheim Co., Ltd., Hyogo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
authors.forename: Kazuya
authors.initials: K
authors.lastname: Maeda
authors.forename: Wataru
authors.initials: W
authors.lastname: Kishimoto
authors.forename: Asami
authors.initials: A
authors.lastname: Saito
authors.forename: Akiko
authors.initials: A
authors.lastname: Harada
authors.forename: Thomas
authors.initials: T
authors.lastname: Ebner
authors.forename: Willy
authors.initials: W
authors.lastname: Roth
authors.forename: Takashi
authors.initials: T
authors.lastname: Igarashi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sugiyama
mesh_terms: D047228:Angiotensin II Type 1 Receptor Blockers / Q000378:metabolism*; D000818:Animals; D001562:Benzimidazoles / Q000378:metabolism*; D001565:Benzoates / Q000378:metabolism*; D002460:Cell Line; D004958:Estradiol / Q000031:analogs & derivatives / Q000378:metabolism; D004970:Estrone / Q000031:analogs & derivatives / Q000494:pharmacology; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D027381:Liver-Specific Organic Anion Transporter 1; D027361:Organic Anion Transporters / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D029362:Organic Anion Transporters, Sodium-Independent / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012709:Serum Albumin / Q000378:metabolism*; D012844:Sincalide / Q000378:metabolism; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; D000077333:Telmisartan; D014162:Transfection
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D001562:Benzimidazoles; D001565:Benzoates; D027381:Liver-Specific Organic Anion Transporter 1; D027361:Organic Anion Transporters; D029362:Organic Anion Transporters, Sodium-Independent; C503999:SLCO1B1 protein, human; C421209:SLCO1B3 protein, human; D012709:Serum Albumin; D000074542:Solute Carrier Organic Anion Transporter Family Member 1B3; C025483:estradiol-17 beta-glucuronide; D004970:Estrone; D004958:Estradiol; D012844:Sincalide; C017296:estrone sulfate; D000077333:Telmisartan