LLC-PK sub 1 cells express Na sup + -lactate cotransport in apical membranes after confluency

Journal Article · Thu Dec 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6227865

Poustis-Delpont, C; Mengual, R; Sudaka, P ^[1]

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1. Faculte de Medecine, Nice (France)

L-({sup 3}H)lactate uptake was characterized in LLC-PK{sub 1} cell apical membrane vesicles obtained by intensive culture on microcarrier beads. The apical membrane preparation technique involved MgCl{sub 2} precipitation. Na{sup +}-dependent L-({sup 3}H)lactate uptake was present only after confluency; its appearance paralleled the subcellular localization of aminopeptidase in apical membranes. L-({sup 3}H)lactate uptake was Na{sup +}-dependent and electrogenic. Only the Na{sup +}-dependent component of L({sup 3}H)lactate uptake was saturable with one family of independent carriers. The apparent affinity constant was 1.1 {plus minus} 0.25 mM and the apparent maximal velocity was 29 {plus minus} 3 nmol{center dot}mg{sup {minus}1}{center dot}min{sup {minus}1}. The Na{sup +}-lactate cotransport stoichiometry was 2 Na{sup +} for 1 lactate. The specificity of the L-lactate transport system was compatible with that of the monocarboxylic acid pathway described previously brush-border membranes of kidney cortex and discrete from the tricarboxylic acid carrier, the D-glucose transporter, and the general pathway for anions. The LLC-PK{sub 1} cell line appears to be a useful tool for study of the regulation of L-lactate uptake and biosynthesis of the renal monocarboxylic acid transporter.

• OSTI ID: 6227865
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 255:6; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
AMINOPEPTIDASES
BIOCHEMICAL REACTION KINETICS
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
ENZYME ACTIVITY
ENZYMES
HYDROGEN COMPOUNDS
HYDROLASES
HYDROXY ACIDS
INULIN
IONS
KIDNEYS
KINETICS
LABELLED COMPOUNDS
LACTIC ACID
MEMBRANE TRANSPORT
MEMBRANES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HYDROLASES
POLYSACCHARIDES
REACTION KINETICS
SACCHARIDES
SODIUM COMPOUNDS
STOICHIOMETRY
TRITIUM COMPOUNDS
UPTAKE