Na sup + -H sup + exchanger in proximal cells isolated from rabbit kidney. I. Functional characteristics

Journal Article · Sun Nov 01 04:00:00 EST 1987 · American Journal of Physiology; (USA)

OSTI ID:6974620

Bidet, M; Tauc, M; Merot, J; Vandewalle, A; Poujeol, P ^[1]

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1. Institut National de la Sante et de la Recherche Medicale (France)

The purpose of this study was to investigate the characteristics of the Na{sup +}-H{sup +} exchange in isolated proximal cells from rabbit kidney cortex. The cells were prepared by mechanical dissociation and sequential passages through nylon meshes. The intracellular pH (pH{sub i}) was measured in a bicarbonate-free medium using the fluorescent dye 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF). Resting pH{sub i} was 7.13 {+-} 0.04. Cells were acid loaded with nigericin in choline solution and H{sup +} efflux, induced by extracellular Na{sup +} (Na{sub e}), was calculated using a buffering power of 23.6 {+-} 0.6 mmol {center dot} l{sup {minus}1} {center dot} pH unit{sup {minus}1} estimated by NH{sub 4}Cl exposure. The intracellular H{sup +} concentration dependence did not follow simple Michaelis-Menten kinetics. Of the different cations tested on pH{sub i} recovery, such as Li{sup +}, choline{sup +}, K{sup +}, and tetramethylammonium, only Li{sup +} induced an alkalinization of acidified cells similar to that of Na{sup +}. {sup 22}Na influx measurements indicated that cellular depletion of Na{sup +} stimulated Na{sup +}-H{sup +} exchange. The results permit the conclusion that the isolation procedures did not impair the main features of the Na{sup +}-H{sup +} antiporter, at least as compared with those previously described in renal brush-border membrane vesicles or in other cellular systems. The integrity of the transporter in isolated proximal cells would permit the direct study of its hormonal and metabolic control.

• OSTI ID: 6974620
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 253:5; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

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551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID CARBONATES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMALS
AROMATICS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BODY
CARBOXYLIC ACIDS
CATIONS
CHARGED PARTICLES
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DYES
ELEMENTARY PARTICLES
EMISSION SPECTRA
FERMIONS
FLUORESCEIN
HADRONS
HALIDES
HALOGEN COMPOUNDS
HYDROXY ACIDS
HYDROXY COMPOUNDS
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KIDNEYS
KINETICS
LIGHT NUCLEI
MAMMALS
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PH VALUE
PHENOLS
POLYPHENOLS
PROTEINS
PROTONS
RABBITS
RADIOISOTOPES
REACTION KINETICS
SODIUM 22
SODIUM CHLORIDES
SODIUM COMPOUNDS
SODIUM ISOTOPES
SPECTRA
UPTAKE
VERTEBRATES
YEARS LIVING RADIOISOTOPES