title: Transporter studies with the 3-O-sulfate conjugate of 17alpha-ethinylestradiol: assessment of human liver drug transporters.
abstract: 17alpha-Ethinylestradiol (EE2), a component of oral contraceptives, is known to undergo considerable first-pass 3-O-sulfation in the intestine and liver. Once formed, the 3-O-sulfate conjugate (EE2-Sul) is detected in circulation at appreciable levels (versus parent EE2) and is present in bile. Therefore, hepatic uptake of EE2-Sul was assessed with suspensions of cryopreserved human primary hepatocytes. In this instance, there was evidence for active (temperature-dependent) uptake, which was described by a two-K(m) (Michaelis constant) model (K(m1) = 220 nM; K(m2) = 15.5 microM). Uptake was inhibited (approximately 90%) by bromosulfophthalein but not by tetraethylammonium or p-aminohippurate. In agreement, EE2-Sul was shown to be a substrate of recombinant organic anion transporter peptides (OATP1B1 and OATP2B1), and Na(+)/taurocholate-cotransporting polypeptide (NTCP), expressed individually in human embryonic kidney (HEK) 293 cells. Transport by OATP1B1 was described by two K(m) values (87 nM and 141 microM), whereas OATP2B1- and NTCP-mediated uptake into HEK-293 cells conformed to single K(m) kinetics (10.7 and 2.6 microM, respectively). EE2-Sul was also assessed as an efflux transporter substrate using membrane vesicles expressing bile salt export pump, breast cancer resistance protein (BCRP), and individual forms of multidrug resistance-associated protein (MRP1, MRP2, and MRP3). Transport studies were also conducted with a cell line expression P-glycoprotein. Only vesicles that contained BCRP exhibited ATP-dependent uptake of EE2-Sul (K(m1) = 2.9 and K(m2) = 307 microM). Collectively, the data show that hepatic uptake of EE2-Sul can be mediated by three transporters (OATP1B1, OATP2B1, and NTCP), whereas biliary excretion of EE2-Sul into bile likely involves BCRP.
authors.affiliation: Department of Metabolism and Pharmacokinetics, Pharmaceutical Candidate Optimization, Bristol-Meyers Squibb, Princeton, New Jersey 08543-4000, USA. yong-hae.han@bms.com
authors.forename: Yong-Hae
authors.initials: YH
authors.lastname: Han
authors.forename: Dennis
authors.initials: D
authors.lastname: Busler
authors.forename: Yang
authors.initials: Y
authors.lastname: Hong
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
authors.forename: Cliff
authors.initials: C
authors.lastname: Chen
authors.forename: A David
authors.initials: AD
authors.lastname: Rodrigues
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics; D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics; D001693:Biological Transport, Active / Q000187:drug effects* / Q000235:genetics; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002461:Cell Line, Transformed; D004997:Ethinyl Estradiol / Q000031:analogs & derivatives* / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D027381:Liver-Specific Organic Anion Transporter 1; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000096:biosynthesis / Q000235:genetics; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D027361:Organic Anion Transporters / Q000096:biosynthesis / Q000235:genetics; D029363:Organic Anion Transporters, Sodium-Dependent / Q000096:biosynthesis / Q000235:genetics; D027981:Symporters / Q000096:biosynthesis / Q000235:genetics; D014162:Transfection / Q000379:methods
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D004997:Ethinyl Estradiol; D027381:Liver-Specific Organic Anion Transporter 1; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D027361:Organic Anion Transporters; D029363:Organic Anion Transporters, Sodium-Dependent; D027981:Symporters; C093491:ABCB11 protein, human; C116614:ABCG2 protein, human; C503999:SLCO1B1 protein, human; C450859:SLCO2B1 protein, human; C071908:sodium-bile acid cotransporter; C025810:ethinylestradiol-3-sulfate