Luminal influences on potassium secretion: transpithelial voltage

D. W. Good, F. S. Wright

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


In vivo microperfusion techniques were used to evaluate whether changes in luminal fluid flow rate affect late distal tubule transpithelial voltage (VTE) and to determine whether flow-dependent changes in K secretion by the renal distal tubule of the rat that we observed previously could be attributed to changes in electrical driving forces. Results showed that increasing the perfusion rate from 6 to 26 nl/min of solutions containing either 94, 46, or 15 mM sodium and 2 mM potassium caused VTE to become 10-12 mV less lumen negative. Since increasing perfusion rate decreases VTE, a flow-dependent voltage change is not responsible for the effect of increasing luminal flow rate to increase distal K secretion. To evaluate the possible contribution of changes in luminal Na and K concentrations to the flow-dependent changes in VTE, the effects of changing either Na or K concentration at constant flow rate were examined. These studies showed that 1) changes in luminal Na concentration within the physiological range (44-94 mM) have no detectable effect on VTE; 2) increases in luminal K concentration within the physiological range (5-16 mM) significantly increase VTE; and 3) the flow-dependent depolarization of VTE is primarily caused by flow-dependent changes in luminal K concentration.

Original languageEnglish (US)
Pages (from-to)F289-F298
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Issue number3
StatePublished - 1980
Externally publishedYes

ASJC Scopus subject areas

  • Physiology


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