Luminal influences on potassium secretion

low sodium concentration.

David Good, H. Velázquez, F. S. Wright

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

In vivo microperfusion techniques were employed in anesthetized rats to determine whether K secretion by renal distal tubules requires the presence of Na in luminal fluid, and, if it does, in what concentration range do changes in Na concentration have the most effect. In a first series of experiments Na in perfusion fluid was replaced at constant Cl with tetramethylammonium (TMA). When the perfusion fluid Na concentration was reduced from 96 or 34 mM to 10 or 3 mM, K secretion was reduced by 50-60% and transepithelial voltage ( VTE ) was reduced by 40-60%. In a second series of experiments, in which NaCl was replaced with urea, perfusion fluid Na concentration again was reduced to 3 mM, and K secretion and VTE were reduced. In a third series of experiments, Na was replaced with rubidium. The reduced K secretion could not be explained solely by changes in electrical driving forces. The results indicate that some luminal Na (half-maximal concentration approx 10 mM) is necessary to permit K secretion to proceed at a normal rate. Considering prior measurements of luminal Na concentration in rat distal tubules, it is unlikely that changes in luminal Na concentration play an important role in regulating the rate of distal K secretion.

Original languageEnglish (US)
JournalThe American journal of physiology
Volume246
Issue number5 Pt 2
StatePublished - May 1984
Externally publishedYes

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Potassium
Perfusion
Sodium
Distal Kidney Tubule
Rubidium
Urea
tetramethylammonium

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Luminal influences on potassium secretion : low sodium concentration. / Good, David; Velázquez, H.; Wright, F. S.

In: The American journal of physiology, Vol. 246, No. 5 Pt 2, 05.1984.

Research output: Contribution to journalArticle

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