Uptake of oleate by isolated rat adipocytes is mediated by a 40-kDa plasma membrane fatty acid binding protein closely related to that in liver and gut
A portion of the hepatocellular uptake of nonesterified long-chain fatty acids is mediated by a specific 40-kDa plasma membrane fatty acid binding protein, which has also been isolated from the gut. To investigate whether a similar transport process exists in other tissues with high transmembrane fatty acid fluxes, initial rates (V/sub O/) of (/sup 3/H)-oleate uptake into isolated rat adipocytes were studied as a function of the concentration of unbound (/sup 3/H)oleate in the medium. V/sub O/ reached a maximum as the concentration of unbound oleate was increased and was significantly inhibited both by phloretin and by prior incubation of the cells with Pronase. A rabbit antibody to the rat liver plasma membrane fatty acid binding protein inhibited adipocyte fatty acid uptake by up to 63% in dose-dependent fashion. Inhibition was noncompetitive; at an immunoglobulin concentration of 250 ..mu..g/ml V/sub max/ was reduced from 2480 /plus minus/ 160 to 1870 /plus minus/ 80 pmol/min per 5 /times/ 10/sup 4/ adipocytes, with no change in K/sub m/. A basic kDa adipocyte plasma membrane fatty acid binding protein, isolated from crude adipocyte plasma membrane fractions, reacted strongly in both agar gel diffusion and electrophoretic blots with the antibody raised against the corresponding hepatic plasma membrane protein. These data indicate that the uptake of oleate by rat adipocytes is mediated by a 40-kDa plasma membrane fatty acid binding protein closely related to that in liver and gut.
- Research Organization:
- Mount Sinai School of Medicine of the City Univ. New York, NY (USA)
- OSTI ID:
- 5983227
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 85:2
- Country of Publication:
- United States
- Language:
- English
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MEMBRANE TRANSPORT
BIOCHEMICAL REACTION KINETICS
OLEIC ACID
UPTAKE
CELL MEMBRANES
ELECTROPHORESIS
FAT CELLS
GASTROINTESTINAL TRACT
LIVER
PROTEINS
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CONNECTIVE TISSUE CELLS
DIGESTIVE SYSTEM
GLANDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
RODENTS
SOMATIC CELLS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques