HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 287/4/F628    most recent 00363.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (20) Citing Articles via Google Scholar Google Scholar Articles by Handlogten, M. E. Articles by Weiner, I. D. Search for Related Content PubMed PubMed Citation Articles by Handlogten, M. E. Articles by Weiner, I. D.

Basolateral ammonium transport by the mouse inner medullary collecting duct cell (mIMCD-3)

⁴Renal Section, North Florida/South Georgia Veterans Health System, ¹Division of Nephrology, Hypertension, and Transplantation, University of Florida College of Medicine, Gainesville, Florida 32610-0224; ²Pathology and Laboratory Medicine, University of Pennsylvania, ³The American Red Cross Philadelphia, Pennsylvania 19104

Submitted 15 October 2003 ; accepted in final form 17 May 2004

The renal collecting duct is the primary site for the ammonia secretion necessary for acid-base homeostasis. Recent studies have identified the presence of putative ammonia transporters in the collecting duct, but whether the collecting duct has transporter-mediated ammonia transport is unknown. The purpose of this study was to examine basolateral ammonia transport in the mouse collecting duct cell (mIMCD-3). To examine mIMCD-3 basolateral ammonia transport, we used cells grown to confluence on permeable support membranes and quantified basolateral uptake of the radiolabeled ammonia analog [¹⁴C]methylammonia ([¹⁴C]MA). mIMCD-3 cell basolateral MA transport exhibited both diffusive and transporter-mediated components. Transporter-mediated uptake exhibited a K_m for MA of 4.6 ± 0.2 mM, exceeded diffusive uptake at MA concentrations below 7.0 ± 1.8 mM, and was competitively inhibited by ammonia with a K_i of 2.1 ± 0.6 mM. Transporter-mediated uptake was not altered by inhibitors of Na⁺-K⁺-ATPase, Na⁺-K⁺-2Cl^– cotransporter, K⁺ channels or KCC proteins, by excess potassium, by extracellular sodium or potassium removal or by varying membrane potential, suggesting the presence of a novel, electroneutral ammonia-MA transport mechanism. Increasing the outwardly directed transmembrane H⁺ gradient increased transport activity by increasing V_max. Finally, mIMCD-3 cells express mRNA and protein for the putative ammonia transporter Rh B-glycoprotein (RhBG), and they exhibit basolateral RhBG immunoreactivity. We conclude that mIMCD-3 cells express a basolateral electroneutral NH₄⁺/H⁺ exchange activity that may be mediated by RhBG.

ammonia; Rh B-glycoprotein

This article has been cited by other articles:

				R. T. Worrell, L. Merk, and J. B. Matthews Ammonium transport in the colonic crypt cell line, T84: role for Rhesus glycoproteins and NKCC1 Am J Physiol Gastrointest Liver Physiol, February 1, 2008; 294(2): G429 - G440. [Abstract] [Full Text] [PDF]

				H.-Y. Kim, C. Baylis, J. W. Verlander, K.-H. Han, S. Reungjui, M. E. Handlogten, and I. D. Weiner Effect of reduced renal mass on renal ammonia transporter family, Rh C glycoprotein and Rh B glycoprotein, expression Am J Physiol Renal Physiol, October 1, 2007; 293(4): F1238 - F1247. [Abstract] [Full Text] [PDF]

				K.-H. Han, H.-Y. Kim, B. P. Croker, S. Reungjui, S.-Y. Lee, J. Kim, M. E. Handlogten, C. A. Adin, and I. D. Weiner Effects of ischemia-reperfusion injury on renal ammonia metabolism and the collecting duct Am J Physiol Renal Physiol, October 1, 2007; 293(4): F1342 - F1354. [Abstract] [Full Text] [PDF]

				K.-H. Han, B. P. Croker, W. L. Clapp, D. Werner, M. Sahni, J. Kim, H.-Y. Kim, M. E. Handlogten, and I. D. Weiner Expression of the Ammonia Transporter, Rh C Glycoprotein, in Normal and Neoplastic Human Kidney J. Am. Soc. Nephrol., October 1, 2006; 17(10): 2670 - 2679. [Abstract] [Full Text] [PDF]

				B. Yang, D. Zhao, E. Solenov, and A. S. Verkman Evidence from knockout mice against physiologically significant aquaporin 8-facilitated ammonia transport Am J Physiol Cell Physiol, September 1, 2006; 291(3): C417 - C423. [Abstract] [Full Text] [PDF]

				R. M. Seshadri, J. D. Klein, T. Smith, J. M. Sands, M. E. Handlogten, J. W. Verlander, and I. D. Weiner Changes in subcellular distribution of the ammonia transporter, Rhcg, in response to chronic metabolic acidosis Am J Physiol Renal Physiol, June 1, 2006; 290(6): F1443 - F1452. [Abstract] [Full Text] [PDF]

				D.-O. D. Mak, B. Dang, I. D. Weiner, J. K. Foskett, and C. M. Westhoff Characterization of ammonia transport by the kidney Rh glycoproteins RhBG and RhCG Am J Physiol Renal Physiol, February 1, 2006; 290(2): F297 - F305. [Abstract] [Full Text] [PDF]

				R. M. Seshadri, J. D. Klein, S. Kozlowski, J. M. Sands, Y.-H. Kim, K.-H. Han, M. E. Handlogten, J. W. Verlander, and I. D. Weiner Renal expression of the ammonia transporters, Rhbg and Rhcg, in response to chronic metabolic acidosis Am J Physiol Renal Physiol, February 1, 2006; 290(2): F397 - F408. [Abstract] [Full Text] [PDF]

				S. D. Lytton, W. Fischer, W. Nagel, R. Haas, and F. X. Beck Production of ammonium by Helicobacter pylori mediates occludin processing and disruption of tight junctions in Caco-2 cells Microbiology, October 1, 2005; 151(10): 3267 - 3276. [Abstract] [Full Text] [PDF]

				M. E. Handlogten, S.-P. Hong, C. M. Westhoff, and I. D. Weiner Apical ammonia transport by the mouse inner medullary collecting duct cell (mIMCD-3) Am J Physiol Renal Physiol, August 1, 2005; 289(2): F347 - F358. [Abstract] [Full Text] [PDF]

				M. E. Handlogten, S.-P. Hong, L. Zhang, A. W. Vander, M. L. Steinbaum, M. Campbell-Thompson, and I. D. Weiner Expression of the ammonia transporter proteins Rh B glycoprotein and Rh C glycoprotein in the intestinal tract Am J Physiol Gastrointest Liver Physiol, May 1, 2005; 288(5): G1036 - G1047. [Abstract] [Full Text] [PDF]