|
|
||||||||
AJP - Renal Physiology, Vol 261, Issue 3 443-F451, Copyright © 1991 by American Physiological Society
ARTICLES |
R. J. Ott, A. C. Hui, G. Yuan and K. M. Giacomini
School of Pharmacy, University of California, San Francisco 94143.
The renal proximal tubule is responsible for the active elimination of organic cations. Studies in brush-border membrane vesicles (BBMV) suggest that active organic cation transport is mediated by an organic cation-proton antiporter. The goals of this study were to determine whether this transporter is expressed in human kidney and to elucidate its characteristics. Transport of the organic cations N1-[3H]methylnicotinamide (NMN) and [14C]tetraethylammonium (TEA) was determined by rapid filtration in BBMV of donor human kidneys. The uptake of NMN and TEA was driven against a concentration gradient by an outwardly directed proton gradient. NMN uptake was inhibited by the organic cations TEA, NMN, quinine, and cimetidine, but was not affected by p-aminohippuric acid, cephalexin, and polyamines. The electroneutral transport of NMN was characterized by a Km of 0.44 +/- 0.07 mM and a Vmax of 24.4 +/- 15.2 pmol.mg protein-1.s-1. The rate of proton efflux from BBMV increased in the presence of an inwardly directed TEA gradient. Preloading BBMV with NMN or TEA trans-stimulated the initial rate of uptake of TEA. Therefore the human proximal tubule expresses an organic cation-proton antiporter in the brush-border membrane. The antiporter is similar to that described in other mammalian species but shows some differences in its transport characteristics.
This article has been cited by other articles:
![]() |
X. Zhang, N. J. Cherrington, and S. H. Wright Molecular identification and functional characterization of rabbit MATE1 and MATE2-K Am J Physiol Renal Physiol, July 1, 2007; 293(1): F360 - F370. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. H. Wright and W. H. Dantzler Molecular and Cellular Physiology of Renal Organic Cation and Anion Transport Physiol Rev, July 1, 2004; 84(3): 987 - 1049. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Rindi and U. Laforenza Thiamine Intestinal Transport and Related Issues: Recent Aspects Experimental Biology and Medicine, September 1, 2000; 224(4): 246 - 255. [Abstract] [Full Text] |
||||
![]() |
H. Ueda, Y. Horibe, K.-J. Kim, and V. H. L. Lee Functional Characterization of Organic Cation Drug Transport in the Pigmented Rabbit Conjunctiva Invest. Ophthalmol. Vis. Sci., March 1, 2000; 41(3): 870 - 876. [Abstract] [Full Text] |
||||
![]() |
M. J. Dresser, A. T. Gray, and K. M. Giacomini Kinetic and Selectivity Differences between Rodent, Rabbit, and Human Organic Cation Transporters (OCT1) J. Pharmacol. Exp. Ther., March 1, 2000; 292(3): 1146 - 1152. [Abstract] [Full Text] |
||||
![]() |
D. H. Sweet and J. B. Pritchard rOCT2 is a basolateral potential-driven carrier, not an organic cation/proton exchanger Am J Physiol Renal Physiol, December 1, 1999; 277(6): F890 - F898. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Dutta, W. Huang, M. Molero, R. Kekuda, F. H. Leibach, L. D. Devoe, V. Ganapathy, and P. D. Prasad Cloning of the Human Thiamine Transporter, a Member of the Folate Transporter Family J. Biol. Chem., November 5, 1999; 274(45): 31925 - 31929. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. R. Villalobos and E. J. Braun Substrate Specificity of Organic Cation/H+ Exchange in Avian Renal Brush-Border Membranes J. Pharmacol. Exp. Ther., December 1, 1998; 287(3): 944 - 951. [Abstract] [Full Text] |
||||
![]() |
L. Zhang, M. J. Dresser, J. K. Chun, P. C. Babbitt, and K. M. Giacomini Cloning and Functional Characterization of a Rat Renal Organic Cation Transporter Isoform (rOCT1A) J. Biol. Chem., June 27, 1997; 272(26): 16548 - 16554. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Zhang, M. J. Dresser, A. T. Gray, S. C. Yost, S. Terashita, and K. M. Giacomini Cloning and Functional Expression of a Human Liver Organic Cation Transporter Mol. Pharmacol., June 1, 1997; 51(6): 913 - 921. [Abstract] [Full Text] |
||||
![]() |
A. E. Busch, S. Quester, J. C. Ulzheimer, S. Waldegger, V. Gorboulev, P. Arndt, F. Lang, and H. Koepsell Electrogenic Properties and Substrate Specificity of the Polyspecific Rat Cation Transporter rOCT1 J. Biol. Chem., December 20, 1996; 271(51): 32599 - 32604. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |