Luminal influences on potassium secretion: Chloride, sodium, and thiazide diuretics

H. Velazquez, D. H. Ellison, F. S. Wright

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


In the presence of Cl-, K+ secretion by the distal tubule saturates with increasing luminal Na+ concentration. Apparent maximal K+ secretion is attained with luminal Na+ concentrations of 40 mM. The results of the present study show that lowering the Cl- concentration of luminal fluid can increase the level of Na+-stimulated K+ secretion beyond the maximal level attained in the presence of Cl-. The effect of lowering luminal Cl- concentration to <10 mM on K+ secretion is greater with higher Na+ concentration. Under these conditions, chlorothiazide decreases K+ secretion. When chlorothiazide is present, changing the Na+ concentration does not affect K+ secretion. Because in rats a thiazide effect is attributed primarily to the distal convoluted tubule (DCT), we postulate that it is primarily DCT cells that increase K+ secretion when Na+ concentration is raised in the presence of low luminal Cl- concentration. We propose that the rat DCT cells have both an absorptive Na+-Cl- cotransport mechanism and a secretory K+-Cl- cotransport mechanism in the luminal membrane that can mediate the apparent exchange of Na+ for K+.

Original languageEnglish (US)
Pages (from-to)F1076-F1082
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Issue number6 31-6
StatePublished - 1992
Externally publishedYes


  • chlorothiazide
  • distal convoluted tubule
  • gluconate
  • kidney
  • potassium-chloride cotransport
  • rat
  • sodium-chloride cotransport
  • transport

ASJC Scopus subject areas

  • Physiology


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