title: Interactions of urate transporter URAT1 in human kidney with uricosuric drugs.
abstract: OBJECTIVE
  Hyperuricaemia is a significant factor in a variety of diseases, including gout and cardiovascular diseases. The kidney plays a dominant role in maintaining plasma urate levels through the excretion process. Human renal urate transporter URAT1 is thought to be an essential molecule that mediates the reabsorption of urate on the apical side of the proximal tubule. In this study the pharmacological characteristics and clinical implications of URAT1 were elucidated.
  
  
  METHODS
  Madin-Darby canine kidney (MDCK) cells stably expressing URAT1 (MDCK-URAT1) were established and examined the interactions of URAT1 with various drugs such as benzbromarone and its metabolites including 6-hydroxybenzbromarone, angiotensin-converting enzyme inhibitors, non-steroidal anti-inflammatory drugs and urate transport inhibitors including E3040 and probenecid.
  
  
  RESULTS
  MDCK-URAT1 cells exhibited a time- and dose-dependent increase in urate uptake, with a Km value of 570.7 µmol/L. When an URAT1-green fluorescent protein fusion protein construct was expressed in MDCK cells, the protein was sorted mainly to the apical side of the membrane. The drugs except for captoril dose-dependently inhibited urate uptake mediated by URAT1, with half maximal inhibitory concentration (IC(50) ) values ranging 0.05-716 µmol/L.
  
  
  CONCLUSIONS
  Comparing these IC(50) values with intratubular concentrations of unbound drugs in humans, it is thought that URAT1 is a target molecule of uricosuric drugs, including 6-hydroxybenzbromarone, probenecid, indomethacin and salicylate, to inhibit urate reabsorption in vivo. In addition, a cell line that stably expressing URAT1 could be a useful tool for the development of uricosuric drugs.
authors.affiliation: Department of Pharmacology and Toxicology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Ho Jung
authors.initials: HJ
authors.lastname: Shin
authors.forename: Michio
authors.initials: M
authors.lastname: Takeda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Enomoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Fujimura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Miyazaki
authors.forename: Naohiko
authors.initials: N
authors.lastname: Anzai
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Endou
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D001553:Benzbromarone / Q000031:analogs & derivatives / Q000494:pharmacology; D052160:Benzothiazoles / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology; D002478:Cells, Cultured; D004285:Dogs; D004656:Enalapril / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D027361:Organic Anion Transporters / Q000378:metabolism*; D027701:Organic Cation Transport Proteins / Q000378:metabolism*; D010653:Phenylbutazone / Q000494:pharmacology; D011339:Probenecid / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012459:Salicylates / Q000494:pharmacology; D013442:Sulfinpyrazone / Q000494:pharmacology; D014527:Uric Acid / Q000378:metabolism*; D014528:Uricosuric Agents / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: C085923:6-hydroxybenzbromarone; D000806:Angiotensin-Converting Enzyme Inhibitors; D000894:Anti-Inflammatory Agents, Non-Steroidal; D052160:Benzothiazoles; D027361:Organic Anion Transporters; D027701:Organic Cation Transport Proteins; D011725:Pyridines; C491241:SLC22A12 protein, human; D012459:Salicylates; D014528:Uricosuric Agents; C095803:E 3040; C004528:benzarone; D014527:Uric Acid; D001553:Benzbromarone; D004656:Enalapril; D002216:Captopril; D010653:Phenylbutazone; D011339:Probenecid; D013442:Sulfinpyrazone; D007213:Indomethacin