TY - JOUR T1 - POSSIBLE INVOLVEMENT OF ORGANIC ANION TRANSPORTER 2 ON THE INTERACTION OF THEOPHYLLINE WITH ERYTHROMYCIN IN THE HUMAN LIVER JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 619 LP - 622 DO - 10.1124/dmd.104.003301 VL - 33 IS - 5 AU - Yasuna Kobayashi AU - Ryoko Sakai AU - Naomi Ohshiro AU - Masayuki Ohbayashi AU - Noriko Kohyama AU - Toshinori Yamamoto Y1 - 2005/05/01 UR - http://dmd.aspetjournals.org/content/33/5/619.abstract N2 - 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 Km values for the uptake of hOat2 that mediated the transport of theophylline and erythromycin were 12.6 μM and 18.5 μM, respectively. The hOat2-mediated uptake of [14C]theophylline and [14C]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. The American Society for Pharmacology and Experimental Therapeutics ER -