Characterization of a Na : K : 2Cl cotransport system in the apical membrane of a renal epithelial cell line (LLC-PK1)

Journal Article · Tue Jan 01 04:00:00 EST 1985 · J. Membr. Biol.; (United States)

DOI:https://doi.org/10.1007/BF01870659· OSTI ID:5687109

Brown, C D; Murer, H

/sup 86/Rb uptake into LLC-PK1 cells (an established renal epithelial cell line) was found to be comprised of an active ouabain-sensitive component, a loop diuretic-sensitive component which was passive and strictly dependent upon the presence of extracellular Na/sup +/ and Cl- for activity, and a leak component. The diuretic-sensitive component of influx was investigated further in apical membrane vesicles derived from these cells. A large fraction of /sup 86/Rb, /sup 22/Na and /sup 36/Cl flux into these vesicles was sensitive to inhibition by furosemide and dependent upon the presence of the other two co-ions, in keeping with the presence of a loop diuretic-sensitive Na/sup +/ : K/sup +/ : Cl- cotransport system. The kinetic parameters for Na/sup +/ and K/sup +/ interaction have been analyzed under initial linear zero trans conditions. The following values were obtained KmNa/sup +/ = 0.42 +/- 0.05 mmol/liter, Vmax = 303 +/- 24 pmol/mg/6 sec; KmK+ = 11.9 +/- 1.0 mmol/liter, VmaxK/sup +/ = 307 +/- 27 pmol/mg/6 sec. For Cl- interaction evidence for two cooperative binding sites with different affinities and different specificities were obtained. Thus, a stoichiometry of 1Na/sup +/ : 1K/sup +/ :2Cl- can be calculated. It is concluded that the apical membrane of LLC-PK1 cells contains a Na/sup +/ : K/sup +/ : 2Cl- co-transport system with properties similar to those described for the thick ascending limb of the loop of Henle.

• Research Organization: Univ. of Zuerich, Switzerland
• OSTI ID: 5687109
• Journal Information: J. Membr. Biol.; (United States), Journal Name: J. Membr. Biol.; (United States) Vol. 2; ISSN JMBBB
• Country of Publication: United States
• Language: English

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551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMAL TISSUES
ANIMALS
ANIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
CHLORIDES
CHLORINE 36
CHLORINE COMPOUNDS
CHLORINE ISOTOPES
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTROLYTES
ELECTRON CAPTURE RADIOISOTOPES
EPITHELIUM
HALIDES
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KIDNEYS
LIGHT NUCLEI
MAMMALS
MATHEMATICAL MODELS
MEMBRANE TRANSPORT
MEMBRANES
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANS
POTASSIUM COMPOUNDS
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM ISOTOPES
SODIUM 22
SODIUM COMPOUNDS
SODIUM ISOTOPES
SWINE
TISSUES
TRACER TECHNIQUES
UPTAKE
VERTEBRATES
YEARS LIVING RADIOISOTOPES