Potassium transport in the mammalian collecting duct.
The mammalian collecting duct plays a dominant role in regulating K(+) excretion by the nephron. The collecting duct exhibits axial and intrasegmental cell heterogeneity and is composed of at least two cell types: collecting duct cells (principal cells) and intercalated cells. Under normal circumstances, the collecting duct cell in the cortical collecting duct secretes K(+), whereas under K(+) depletion, the intercalated cell reabsorbs K(+). Assessment of the electrochemical driving forces and of membrane conductances for transcellular and paracellular electrolyte movement, the characterization of several ATPases, patch-clamp investigation, and cloning of the K(+) channel have provided important insights into the role of pumps and channels in those tubule cells that regulate K(+) secretion and reabsorption. This review summarizes K(+) transport properties in the mammalian collecting duct. Special emphasis is given to the mechanisms of how K(+) transport is regulated in the collecting duct.
Muto
S
S
Department of Nephrology, Jichi Medical School, Minamikawachi, Tochigi, Japan. smuto@jichi.ac.jp
D000136:Acid-Base Equilibrium / Q000502:physiology; D000818:Animals; D005938:Glucocorticoids / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D017136:Ion Transport / Q000187:drug effects / Q000502:physiology; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000378:metabolism*; D008322:Mammals / Q000378:metabolism*; D008901:Mineralocorticoids / Q000378:metabolism / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000145:classification / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D014667:Vasopressins / Q000378:metabolism / Q000494:pharmacology
D005938:Glucocorticoids; C086989:KCNJ1 protein, human; D008901:Mineralocorticoids; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D014667:Vasopressins; D011188:Potassium