Asymmetry of Na-Cl cotransport in human erythrocytes
- Syracuse Univ., NY (USA)
The Na-K-Cl cotransport system in human erythrocytes was studied by measuring net influxes and effluxes of Na and K. The influx of K was shown to be stimulated by Na and the influx of Na was stimulated by K, satisfying the fundamental criterion of cotransport. In addition, these mutually stimulation cation influxes had a stoichiometry of 1:1 and were entirely inhibited by furosemide; these results are also consistent with cotransport. Furthermore, the mutually stimulating influxes were entirely dependent on Cl, since they were abolished when nitrate was substituted for Cl. In contrast, cotransport, defined by mutual dependence of fluxes, was not detected in the outward direction over a range of cellular Na and K concentrations from 0 to 50 mmol/l cells. The cotransport pathway did, however, appear to mediate a Na-stimulated K efflux (but no K-stimulated Na efflux) and furosemide-inhibitable effluxes of both Na and K. Nitrate (but not sulfate) appeared to substitute for chloride in promoting Na-stimulated K efflux. Thus the Na-K-Cl cotransport system in human red cells is intrinsically asymmetric, and mediates coupled cation fluxes readily only in the inward direction.
- OSTI ID:
- 6870877
- Journal Information:
- American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 254:2; ISSN 0002-9513; ISSN AJPHA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMALS
ASYMMETRY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CHARGED PARTICLES
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
ERYTHROCYTES
HALIDES
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MAN
MATERIALS
MEMBRANE TRANSPORT
MINUTES LIVING RADIOISOTOPES
NITRATES
NITROGEN COMPOUNDS
NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
PRIMATES
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM ISOTOPES
SODIUM CHLORIDES
SODIUM COMPOUNDS
STOICHIOMETRY
SULFATES
SULFUR COMPOUNDS
VERTEBRATES