Potassium transport by turtle colon: Active secretion and active absorption

D. R. Halm, D. C. Dawson

Research output: Contribution to journalArticle

Abstract

Measurement of transepithelial potassium fluxes in the absence of transmural electrochemical potential gradients showed that the isolated turtle colon can actively absorb and actively secrete K+. Under short-circuit conditions the active secretory flow was inhibited by mucosal amiloride, whereas the absorptive flow was unaffected by the diuretic. The effects of ouabain and barium on secretory flow were consistent with a simple model involving basolateral uptake by an Na+-K+-ATPase and conductive exit across the apical and basolateral membranes. The active absorptive flux was blocked by mucosal ouabain and by serosal barium. The opposing active flows clearly represented cellular K+ transport, whereas paracellular K+ flows behaved as expected for a free-solution shunt.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume15
Issue number2
StatePublished - 1984
Externally publishedYes

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ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

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