2007 JASN IMPACT FACTOR 7.111	HOME   AUTHOR INFO   EDITORIAL BOARD   SUBSCRIBE   FEEDBACK   ALERTS   HELP
advanced	CURRENT ISSUE	ARCHIVES	JASN Express	ONLINE SUBMISSION

This Article Full Text Full Text (PDF) 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 Google Scholar Google Scholar Articles by Wall, S. M. Articles by Fischer, M. P. Search for Related Content PubMed PubMed Citation Articles by Wall, S. M. Articles by Fischer, M. P.

Contribution of the Na⁺-K⁺-2Cl^- Cotransporter (NKCC1) to Transepithelial Transport of H⁺, NH₄⁺, K⁺, and Na⁺ in Rat Outer Medullary Collecting Duct

Division of Renal Diseases and Hypertension, University of Texas, Medical School at Houston, Houston, Texas.

Correspondence to: Dr. Susan M. Wall, Division of Renal Diseases and Hypertension, University of Texas, Medical School at Houston, 6431 Fannin, M.S.B. 4.148, Houston, TX 77030. Phone: 713-500-6868; Fax: 713-500-6882; E-mail: susan.m.wall{at}uth.tmc.edu

ABSTRACT. In rat kidney, the "secretory" isoform of the Na-K-Cl cotransporter, NKCC1 (BSC-2), localizes to the basolateral membrane of the intercalated cell, the acid secreting cell of the outer medullary collecting duct (OMCD). This laboratory has reported that NKCC1 mediates Cl^- uptake across the basolateral membrane in series with Cl^- secretion across the apical membrane in rat OMCD. NKCC1 transports NH₄⁺, K⁺, and Na⁺ as well as Cl^-; therefore, a role for the cotransporter in the process of HCl, NH₄Cl, KCl, and NaCl secretion has been suggested. Thus, it was determined if bumetanide, an inhibitor of NKCC1, alters transepithelial cation transport in rat OMCD. OMCD tubules from deoxycorticosterone pivalate (DOCP)–treated rats were perfused in vitro. Hydration of CO₂, rather than NH₄⁺, provides the principle source of H⁺ for net acid secretion. In HCO₃^-/CO₂-buffered solutions, no effect of bumetanide on net K⁺ flux was detected. Under some conditions, bumetanide addition resulted in a small reduction in secretion of net H⁺ equivalents. Transepithelial Na⁺ flux, J_Na, was -1.5 ± 1.7 pmol/mm per min, values not different from zero. However, with the application of bumetanide to the bath, J_Na was +5.2 ± 1.3 pmol/mm per min (P < 0.05), which indicates net Na⁺ absorption. In conclusion, inhibition of NKCC1 in rat OMCD changes transepithelial movement of Na⁺ and Cl^-. The role of NKCC1 in the secretion of net H⁺ equivalents is small.

This article has been cited by other articles:

				S. M. Wall, M. A. Knepper, K. A. Hassell, M. P. Fischer, A. Shodeinde, W. Shin, T. D. Pham, J. W. Meyer, J. N. Lorenz, W. H. Beierwaltes, et al. Hypotension in NKCC1 null mice: role of the kidneys Am J Physiol Renal Physiol, February 1, 2006; 290(2): F409 - F416. [Abstract] [Full Text] [PDF]

				R. Chambrey, D. Goossens, S. Bourgeois, N. Picard, M. Bloch-Faure, F. Leviel, V. Geoffroy, M. Cambillau, Y. Colin, M. Paillard, et al. Genetic ablation of Rhbg in the mouse does not impair renal ammonium excretion Am J Physiol Renal Physiol, December 1, 2005; 289(6): F1281 - F1290. [Abstract] [Full Text] [PDF]

				S. M. Wall, M. P. Fischer, D. M. Glapion, and M. De La Calzada ANG II reduces net acid secretion in rat outer medullary collecting duct Am J Physiol Renal Physiol, November 1, 2003; 285(5): F930 - F937. [Abstract] [Full Text] [PDF]

				M. J. Bergeron, E. Gagnon, B. Wallendorff, J.-Y. Lapointe, and P. Isenring Ammonium transport and pH regulation by K+-Cl- cotransporters Am J Physiol Renal Physiol, July 1, 2003; 285(1): F68 - F78. [Abstract] [Full Text] [PDF]

Copyright © 2008 by the American Society of Nephrology. Online ISSN: 1533-3450 Print ISSN: 1046-6673