Chronic metabolic acidosis enhances NHE-3 protein abundance and transport activity in the rat thick ascending limb by increasing NHE-3 mRNA

Kamel Laghmani, Pascale Borensztein, Patrice Ambühl, Marc Froissart, Maurice Bichara, Orson W. Moe, Robert J. Alpern, Michel Paillard

Research output: Contribution to journalArticle

82 Citations (Scopus)

Abstract

Chronic metabolic acidosis (CMA) is associated with an adaptive increase in the bicarbonate absorptive capacity of the rat medullary thick ascending limb (MTAL). To specify whether NHE-3, the apical MTAL Na/H exchanger, is involved in this adaptation, NHE-3 mRNA was quantified by a competitive RT- PCR using an internal standard which differed from the wild-type NHE-3 mRNA by an 80-bp deletion. CMA increased NHE-3 mRNA from 0.025 ± 0.003 to 0.042 ± 0.009 amol/ng total RNA (P < 0.005). NHE-3 transport activity was measured as the initial proton flux rate calculated from the Na-dependent cell pH recovery of Na-depleted acidified MTAL cells in the presence of 50 μM HOE694 which specifically blocks NHE-1, the basolateral MTAL NHE isoform. CMA caused a 68% increase in NHE-3 transport activity (P < 0.001). In addition, CMA was associated with a 71% increase in NHE-3 protein abundance (P < 0.05) as determined by Western blot analysis on MTAL membranes using a polyclonal antiserum directed against a cytoplasmic epitope of rat NHE-3. Thus, NHE-3 adapts to CMA in the rat MTAL via an increase in the mRNA transcript that enhances NHE-3 protein abundance and transport activity.

Original languageEnglish (US)
Pages (from-to)24-30
Number of pages7
JournalJournal of Clinical Investigation
Volume99
Issue number1
StatePublished - Jan 1 1997

Fingerprint

Protein Transport
Acidosis
Extremities
Messenger RNA
Sodium-Hydrogen Antiporter
Bicarbonates
sodium-hydrogen exchanger 3
Protons
Immune Sera
Epitopes
Protein Isoforms
Western Blotting
RNA
Polymerase Chain Reaction
Membranes

Keywords

  • acidosis
  • kidney
  • Na/H exchange
  • NHE-3

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Chronic metabolic acidosis enhances NHE-3 protein abundance and transport activity in the rat thick ascending limb by increasing NHE-3 mRNA. / Laghmani, Kamel; Borensztein, Pascale; Ambühl, Patrice; Froissart, Marc; Bichara, Maurice; Moe, Orson W.; Alpern, Robert J.; Paillard, Michel.

In: Journal of Clinical Investigation, Vol. 99, No. 1, 01.01.1997, p. 24-30.

Research output: Contribution to journalArticle

Laghmani, K, Borensztein, P, Ambühl, P, Froissart, M, Bichara, M, Moe, OW, Alpern, RJ & Paillard, M 1997, 'Chronic metabolic acidosis enhances NHE-3 protein abundance and transport activity in the rat thick ascending limb by increasing NHE-3 mRNA', Journal of Clinical Investigation, vol. 99, no. 1, pp. 24-30.
Laghmani, Kamel ; Borensztein, Pascale ; Ambühl, Patrice ; Froissart, Marc ; Bichara, Maurice ; Moe, Orson W. ; Alpern, Robert J. ; Paillard, Michel. / Chronic metabolic acidosis enhances NHE-3 protein abundance and transport activity in the rat thick ascending limb by increasing NHE-3 mRNA. In: Journal of Clinical Investigation. 1997 ; Vol. 99, No. 1. pp. 24-30.
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