Na sup + -H sup + exchanger in proximal cells isolated from kidney. II. Short-term regulation by glucocorticoids

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

OSTI ID:6834194

Bidet, M; Merot, J; Tauc, M; 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 acute regulation by glucocorticoid of the Na{sup +}-H{sup +} exchanger in isolated renal proximal cells of the rabbit. The changes of intracellular pH (pH{sub i}) were determined in a bicarbonate-free buffer by the use of a fluorescent pH probe that may be trapped intracellularly, 2,7-biscarboxyethyl- 5(6)- carboxyfluorescein (BCECF). The activity of the Na{sup +}-H{sup +} exchanger was estimated by measuring the Na{sup +}-induced H{sup +} efflux in BCECF-loaded cells acid loaded with nigericin in choline medium. The uptake of 1.5 mM {sup 22}Na was also studied in Na{sup +}-depleted cells. Acute application of dexamethasone increased the activity of the Na{sup +}-H{sup +} exchanger. The effect on the kinetics of amiloride-sensitive Na{sup +}-H{sup +} exchange indicated that dexamethasone (DEX) increased the activity by increasing the V{sub max} of the carrier for external sodium and for external H{sup +}. The apparent affinity was not modified either for Na{sup +} or for H{sup +}. The glucocorticoid action was undetectable after pretreatment of cells with actinomycin D or cycloheximide. Acute glucocorticoid activation of the Na{sup +}-H{sup +} exchanger in isolated proximal cells required RNA and protein synthesis and was consistent with an increase in the number of carriers in the membrane.

• OSTI ID: 6834194
• 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

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ALCOHOLS
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AROMATICS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHLORIDES
CHLORINE COMPOUNDS
CHOLINE
CORTICOSTEROIDS
DEXAMETHASONE
DRUGS
DYES
ELEMENTARY PARTICLES
FERMIONS
FLUORESCEIN
GLUCOCORTICOIDS
HADRONS
HALIDES
HALOGEN COMPOUNDS
HYDROXY ACIDS
HYDROXY COMPOUNDS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KETONES
KIDNEYS
KINETICS
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
MEMBRANES
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PH VALUE
PHENOLS
POLYPHENOLS
PREGNANES
PROTEINS
PROTONS
QUATERNARY COMPOUNDS
RABBITS
RADIOISOTOPES
REACTION KINETICS
SODIUM 22
SODIUM CHLORIDES
SODIUM COMPOUNDS
SODIUM ISOTOPES
STEROIDS
UPTAKE
VERTEBRATES
YEARS LIVING RADIOISOTOPES