Sodium-hydrogen exchange system in LLC-PK/sub 1/ epithelium

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:6351694

Moran, A

Sodium influx into LLC-PK/sub 1/ cells has been characterized. The main amiloride-sensitive pathway for sodium entry through the apical membrane in this cell line is sodium-hydrogen exchange with an apparent K/sub m/ for sodium of 19 mM. Influx is pH dependent and is amiloride sensitive with K/sub 1/2/ of 30 ..mu..M. Inhibition of the sodium transport by protons is consistent with an interaction of H/sup +/ ions at a single site having an apparent pK/sub H/ of 7.2. These data are similar to those reported previously for brush border membrane (BBM) isolated from kidney proximal tubule. However, in contrast to previously published reports, H/sup +/ does not compete with amiloride in blocking /sup 22/Na/sup +/ influx and exhibits a mixed inhibition with sodium ions. The latter, together with a direct and independent assessment of amiloride and sodium interaction, indicates that amiloride does not compete with sodium for the same site. Possible explanations for the discrepancy in the literature concerning the interaction of Na/sup +/, H/sup +/, and amiloride with the Na/sup +/-H/sup +/ exchanger and the characteristics of the Na/sup +/-H/sup +/ exchange system in LLC-PK/sub 1/ are discussed.

• Research Organization: Armed Forces Radiobiology Research Institute, Bethesda, MD
• OSTI ID: 6351694
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 252:1; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMAL TISSUES
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BODY
CATIONS
CHARGED PARTICLES
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DIURETICS
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELEMENTARY PARTICLES
EPITHELIUM
FERMIONS
HADRONS
HALIDES
HALOGEN COMPOUNDS
IONS
ISOTOPES
KIDNEYS
LABELLED COMPOUNDS
LIGHT NUCLEI
MEMBRANE TRANSPORT
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANS
PH VALUE
PROTONS
RADIOISOTOPES
SODIUM 22
SODIUM CHLORIDES
SODIUM COMPOUNDS
SODIUM ISOTOPES
TISSUES
TRITIUM COMPOUNDS
YEARS LIVING RADIOISOTOPES