BK channels in the kidney: role in K(+) secretion and localization of molecular components

Am J Physiol Renal Physiol. 2006 Sep;291(3):F517-29. doi: 10.1152/ajprenal.00118.2006. Epub 2006 Jun 13.


Although it is generally accepted that ROMK is the K(+) secretory channel in the mammalian distal nephron, recent in vitro and in vivo studies have provided evidence that large-conductance Ca(2+)-activated K(+) channels (BK, or maxi K) also secrete K(+) in renal tubules. This review assesses the current evidence relating BK channels with K(+) secretion. We shall consider the component proteins of the BK channel, their localization with respect to segment and cell type, and the electrophysiological forces involved in K(+) secretion. Although the majority of studies have focused on a role for BK channels in flow-mediated K(+) secretion, this review also considers a potential role for BK channels in high-K diet-induced K(+) secretion. The division of workload between ROMK and BK is discussed as a mechanism for ensuring a constant plasma K(+) concentration.

Publication types

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

MeSH terms

  • Animals
  • Cell Compartmentation / physiology
  • Electrophysiology
  • Humans
  • Kidney / anatomy & histology
  • Kidney / physiology*
  • Large-Conductance Calcium-Activated Potassium Channels / metabolism
  • Large-Conductance Calcium-Activated Potassium Channels / physiology*
  • Potassium / metabolism*
  • Potassium Channels, Inwardly Rectifying / physiology*


  • KCNJ1 protein, human
  • Large-Conductance Calcium-Activated Potassium Channels
  • Potassium Channels, Inwardly Rectifying
  • Potassium