title: Possible involvement of organic anion transporter 2 on the interaction of theophylline with erythromycin in the human liver.
abstract: Organic anion transporter 2 (Oat2 [SLC22A7]) is a multispecific organic anion transporter. Although several substrates of human Oat2 (hOat2) have been elucidated, a possible involvement of hOat2 in drug interaction is less defined. The purpose of this study was to investigate the interaction of theophylline with erythromycin mediated by hOat2 using a Xenopus laevis oocyte expression system. When expressed in Xenopus oocytes, hOat2 mediated the transport of theophylline and erythromycin. The finding indicates that the two compounds are novel substrates for hOat2. The apparent K(m) values for the uptake of hOat2 that mediated the transport of theophylline and erythromycin were 12.6 muM and 18.5 muM, respectively. The hOat2-mediated uptake of [(14)C]theophylline and [(14)C]erythromycin was cis-inhibited by adding erythromycin and theophylline, respectively. Our present findings suggest that hOat2 may, at least in part, be involved in the theophylline-erythromycin interaction in the human liver.
authors.affiliation: Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Showa University, Shinagawa-ku, Tokyo, Japan.
authors.forename: Yasuna
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Ryoko
authors.initials: R
authors.lastname: Sakai
authors.forename: Naomi
authors.initials: N
authors.lastname: Ohshiro
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohbayashi
authors.forename: Noriko
authors.initials: N
authors.lastname: Kohyama
authors.forename: Toshinori
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001798:Blood Proteins / Q000378:metabolism; D004347:Drug Interactions; D004917:Erythromycin / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D029362:Organic Anion Transporters, Sodium-Independent / Q000502:physiology*; D010726:Phosphodiesterase Inhibitors / Q000493:pharmacokinetics*; D011485:Protein Binding; D018075:RNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D013806:Theophylline / Q000493:pharmacokinetics*; D014982:Xenopus laevis
chemical_list: D000900:Anti-Bacterial Agents; D001798:Blood Proteins; D029362:Organic Anion Transporters, Sodium-Independent; D010726:Phosphodiesterase Inhibitors; D018075:RNA, Complementary; C490280:SLC22A7 protein, human; D004917:Erythromycin; D013806:Theophylline