Novel amiloride-sensitive sodium-dependent proton secretion in the mouse proximal convoluted tubule

Joo Young Choi, Mehul Shah, Min Goo Lee, Patrick J. Schultheis, Gary E. Shull, Shmuel Muallem, Michel Baum

Research output: Contribution to journalArticle

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Abstract

The proximal convoluted tubule (PCT) reabsorbs most of the filtered bicarbonate. Proton secretion is believed to be mediated predominantly by an apical membrane Na+/H+ exchanger (NHE). Several NHE isoforms have been cloned, but only NHE3 and NHE2 are known to be present on the apical membrane of the PCT. Here we examined apical membrane PCT sodium-dependent proton secretion of wild-type (NHE3(+/+)/NHE2(+/+)), NHE3(-/-), NHE2(-/-), and double-knockout NHE3(-/-)/NHE2(-/-) mice to determine their relative contribution to luminal proton secretion. NHE2(-/-) and wild-type mice had comparable rates of sodium-dependent proton secretion. Sodium-dependent proton secretion in NHE3(-/-) mice was approximately 50% that of wild-type mice. The residual sodium-dependent proton secretion was inhibited by 100 μM 5-(N-ethyl-N-isopropyl) amiloride (EIPA). Luminal sodium-dependent proton secretion was the same in NHE3(-/-)/NHE2(-/-) as in NHE3(-/-) mice. These data point to a previously unrecognized Na+-dependent EIPA-sensitive proton secretory mechanism in the proximal tubule that may play an important role in acid-base homeostasis.

Original languageEnglish (US)
Pages (from-to)1141-1146
Number of pages6
JournalJournal of Clinical Investigation
Volume105
Issue number8
StatePublished - Apr 2000

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Amiloride
Protons
Sodium
Sodium-Hydrogen Antiporter
Membranes
Bicarbonates
Protein Isoforms
Homeostasis
Acids

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Choi, J. Y., Shah, M., Lee, M. G., Schultheis, P. J., Shull, G. E., Muallem, S., & Baum, M. (2000). Novel amiloride-sensitive sodium-dependent proton secretion in the mouse proximal convoluted tubule. Journal of Clinical Investigation, 105(8), 1141-1146.

Novel amiloride-sensitive sodium-dependent proton secretion in the mouse proximal convoluted tubule. / Choi, Joo Young; Shah, Mehul; Lee, Min Goo; Schultheis, Patrick J.; Shull, Gary E.; Muallem, Shmuel; Baum, Michel.

In: Journal of Clinical Investigation, Vol. 105, No. 8, 04.2000, p. 1141-1146.

Research output: Contribution to journalArticle

Choi, JY, Shah, M, Lee, MG, Schultheis, PJ, Shull, GE, Muallem, S & Baum, M 2000, 'Novel amiloride-sensitive sodium-dependent proton secretion in the mouse proximal convoluted tubule', Journal of Clinical Investigation, vol. 105, no. 8, pp. 1141-1146.
Choi JY, Shah M, Lee MG, Schultheis PJ, Shull GE, Muallem S et al. Novel amiloride-sensitive sodium-dependent proton secretion in the mouse proximal convoluted tubule. Journal of Clinical Investigation. 2000 Apr;105(8):1141-1146.
Choi, Joo Young ; Shah, Mehul ; Lee, Min Goo ; Schultheis, Patrick J. ; Shull, Gary E. ; Muallem, Shmuel ; Baum, Michel. / Novel amiloride-sensitive sodium-dependent proton secretion in the mouse proximal convoluted tubule. In: Journal of Clinical Investigation. 2000 ; Vol. 105, No. 8. pp. 1141-1146.
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