Effects of dietary K on cell-surface expression of renal ion channels and transporters

Am J Physiol Renal Physiol. 2010 Oct;299(4):F890-7. doi: 10.1152/ajprenal.00323.2010. Epub 2010 Aug 11.


Changes in apical surface expression of ion channels and transporters in the superficial rat renal cortex were assessed using biotinylation and immunoblotting during alterations in dietary K intake. A high-K diet increased, and a low-K diet decreased, both the overall and surface abundance of the β- and γ-subunits of the epithelial Na channel (ENaC). In the case of γ-ENaC, the effect was specific for the 65-kDa cleaved form of the protein. The overall amount of α-ENAC was also increased with increasing K intake. The total expression of the secretory K(+) channels (ROMK) increased with a high-K diet and decreased with a low-K diet. The surface expression of ROMK increased with high K intake but was not significantly altered by a low-K diet. In contrast, the amounts of total and surface protein representing the thiazide-sensitive NaCl cotransporter (NCC) decreased with increasing K intake. We conclude that modulation of K(+) secretion in response to changes in dietary K intake involves changes in apical K(+) permeability through regulation of K(+) channels and in driving force subsequent to alterations in both Na delivery to the distal nephron and Na(+) uptake across the apical membrane of the K(+) secretory cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Epithelial Sodium Channels / drug effects
  • Epithelial Sodium Channels / metabolism*
  • Female
  • Kidney Cortex / drug effects
  • Kidney Cortex / metabolism*
  • Male
  • Models, Animal
  • Nephrons / metabolism
  • Oocytes / metabolism
  • Potassium Channels / drug effects
  • Potassium Channels / metabolism*
  • Potassium Channels, Inwardly Rectifying / metabolism
  • Potassium, Dietary / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Sodium / metabolism
  • Sodium Chloride Symporters / drug effects
  • Sodium Chloride Symporters / metabolism*
  • Xenopus laevis


  • Epithelial Sodium Channels
  • Kcnj1 protein, rat
  • Potassium Channels
  • Potassium Channels, Inwardly Rectifying
  • Potassium, Dietary
  • Sodium Chloride Symporters
  • Sodium