Sodium-hydrogen exchange system in brush border membranes from cortical and medullary regions of the proximal tubule

Arie Moran, Gerti Stange, Heini Murer

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The Na+/H+ exchange system was studied in brush border membrane vesicles isolated from cortical and medullary regions of the proximal tubule of rabbit kidney. The activity of the exchanger was assessed by measuring hydrogen influx (monitored by acridine orange fluorescence), 22Na influx and the sensitivity of these fluxes to amiloride and its analogue ethylisopropyl amiloride. In contrast to previously published data (indicating the absence of pH-gradient driven and amiloride sensitive 22Na-influx in medullary site vesicles (13,15)), Na+/H+ exchange activity could be detected in both membrane preparations by sodium tracer and fluorescence detection of hydrogen influx. Amiloride inhibition of 22Na influx was more effectively protected by increasing sodium concentration in cortical than in medullary vesicles, suggesting differences in the action of amiloride in these preparations.

Original languageEnglish
Pages (from-to)269-275
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume163
Issue number1
DOIs
StatePublished - 30 Aug 1989

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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