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 00:00:00 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), Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

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