Details

Autor(en) / Beteiligte

• Stremmel, Wolfgang
• Strohmeyer, Georg
• Berk, Paul D.

Titel

Hepatocellular Uptake of Oleate is Energy Dependent, Sodium Linked, and Inhibited by an Antibody to a Hepatocyte Plasma Membrane Fatty Acid Binding Protein

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 1986-06, Vol.83 (11), p.3584-3588

Ort / Verlag

Washington, DC: National Academy of Sciences of the United States of America

Erscheinungsjahr

1986

Quelle

Open access e-journals list

Beschreibungen/Notizen

• Several studies suggest that a portion of hepatocellular nonesterified fatty acid uptake may be carrier mediated. To further investigate this process, initial rates (V0) of [14C]oleate uptake into rat hepatocytes, isolated by collagenase perfusion and incubated at 37 degrees C with oleate in the presence of bovine serum albumin, were studied as a function of the concentration of unbound [14C]oleate in the medium. V0 was saturable with increasing unbound oleate concentration (Km = 8.3 × 10-8 M; Vmax = 197 pmol per min per 5 × 104 hepatocytes) and was not inhibited by up to 40 μ M sulfobromophthalein, taurocholate, or cholic acid. Oleate uptake was sodium dependent. V0 was significantly diminished when Li+, K+, choline, or sucrose were substituted for Na+ in the incubation medium and was reduced 46% by 1 mM ouabain. Uptake was also markedly reduced after exposure of cells to metabolic inhibitors (e.g., 2,4-dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, antimycin, KCN). To evaluate the physiologic significance of the previously isolated rat liver plasma membrane fatty acid-binding protein, the effect of an antibody directed against this protein on hepatocellular [14C]oleate uptake was examined. Preincubation of hepatocytes with the IgG fraction of this antiserum inhibited V0 of [14C]oleate by up to 65% in dose-related fashion, without altering V0 for [35S]sulfobromophthalein,[14C]tauro cholate, or [3H]cholate. These data indicate that at least a portion of hepatocellular oleate uptake is energy dependent, sodium linked, and mediated by a specific liver plasma membrane-fatty acid-binding protein.