Takeda Michio, Khamdang Suparat, Narikawa Shinichi, Kimura Hiroaki, Hosoyamada Makoto, Cha Seok Ho, Sekine Takashi, Endou Hitoshi
Department of Pharmacology and Toxicology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo 181-8611, Japan.
J Pharmacol Exp Ther. 2002 Aug;302(2):666-71. doi: 10.1124/jpet.102.034330.
Life-threatening drug interactions are known to occur between methotrexate and nonsteroidal anti-inflammatory drugs (NSAIDs), probenecid, and penicillin G. The purpose of this study was to characterize methotrexate transport, as well as to determine the site and the mechanism of drug interactions in the proximal tubule. Mouse proximal tubule cells stably expressing basolateral human organic anion transporters (hOAT1 and hOAT3) and apical hOAT (hOAT4) were established. The K(m) values for hOAT1-, hOAT3-, and hOAT4-mediated methotrexate uptake were 553.8 microM, 21.1 microM, and 17.8 microM, respectively. NSAIDs (salicylate, ibuprofen, ketoprofen, phenylbutazone, piroxicam, and indomethacin), probenecid, and penicillin G dose dependently inhibited methotrexate uptake mediated by hOAT1, hOAT3, and hOAT4. Kinetic analysis of inhibitory effects of these drugs on hOAT3-mediated methotrexate uptake revealed that these inhibitions were competitive. The K(i) values for the effects of salicylate, phenylbutazone, indomethacin, and probenecid on hOAT3-mediated methotrexate uptake were comparable with therapeutically relevant plasma concentrations of unbound drugs. In addition, in the presence of human serum albumin, the K(i) values were comparable with therapeutically relevant total plasma concentrations of drugs. In conclusion, these results suggest that methotrexate is taken up via hOAT3 and hOAT1 at the basolateral side of the proximal tubule and effluxed or taken up at the apical side via hOAT4. In addition, hOAT1, hOAT3, and hOAT4 are the sites of drug interactions between methotrexate and NSAIDs, probenecid, and penicillin G. Furthermore, it was predicted that hOAT3 is the site of drug interactions between methotrexate and salicylate, phenylbutazone, indomethacin, and probenecid in vivo.
已知甲氨蝶呤与非甾体抗炎药（NSAIDs）、丙磺舒和青霉素G之间会发生危及生命的药物相互作用。本研究的目的是表征甲氨蝶呤的转运情况，并确定近端小管中药物相互作用的部位和机制。建立了稳定表达基底侧人有机阴离子转运体（hOAT1和hOAT3）和顶端hOAT（hOAT4）的小鼠近端小管细胞。hOAT1、hOAT3和hOAT4介导的甲氨蝶呤摄取的K(m)值分别为553.8 microM、21.1 microM和17.8 microM。NSAIDs（水杨酸盐、布洛芬、酮洛芬、保泰松、吡罗昔康和吲哚美辛）、丙磺舒和青霉素G剂量依赖性地抑制hOAT1、hOAT3和hOAT4介导的甲氨蝶呤摄取。对这些药物对hOAT3介导的甲氨蝶呤摄取的抑制作用进行动力学分析表明，这些抑制作用是竞争性的。水杨酸盐、保泰松、吲哚美辛和丙磺舒对hOAT3介导的甲氨蝶呤摄取的影响的K(i)值与未结合药物的治疗相关血浆浓度相当。此外，在人血清白蛋白存在的情况下，K(i)值与药物的治疗相关总血浆浓度相当。总之，这些结果表明，甲氨蝶呤在近端小管基底侧通过hOAT3和hOAT1摄取，并在顶端侧通过hOAT4流出或摄取。此外，hOAT1、hOAT3和hOAT4是甲氨蝶呤与NSAIDs、丙磺舒和青霉素G之间药物相互作用的部位。此外，据预测，hOAT3是甲氨蝶呤与水杨酸盐、保泰松、吲哚美辛和丙磺舒在体内药物相互作用的部位。
