Extracellular fatty acids are not utilized directly for the synthesis of very-low-density lipoprotein in primary cultures of rat hepatocytes
| Autor: | Charles E. Sparks, S M Bartlett, Janet D. Sparks, G F Gibbons |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Very low-density lipoprotein
Lipoproteins VLDL Biology digestive system Biochemistry chemistry.chemical_compound Ketogenesis Extracellular Animals Molecular Biology Cells Cultured Apolipoproteins B chemistry.chemical_classification Esterification Fatty Acids food and beverages nutritional and metabolic diseases Fatty acid Cell Biology Rats Kinetics Oleic acid Liver chemistry Ketone bodies lipids (amino acids peptides and proteins) Oxidation-Reduction Intracellular Research Article Lipoprotein |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bj2870749 |
| Popis: | In hepatocytes cultured in the presence of oleate (initial concn. 0.75 mM), the secretion of very-low-density lipoprotein (VLDL) triacylglycerol and, to a lesser extent, apoprotein B (apoB) increased with time, whereas there was a large decline in the extracellular concentration of fatty acid. There was thus no synchronous relationship between the extracellular fatty acid concentration and the secretion of VLDL. Rather, the appearance of VLDL in the medium was dependent on the intracellular triacylglycerol concentration. At a given concentration of extracellular fatty acid, cells depleted of triacylglycerol secreted less VLDL triacylglycerol and apoB than did control cells. A similar pattern was observed for triacylglycerol newly synthesized from extracellular [3H]oleate. By contrast, the synthesis and output of ketone bodies were directly dependent on the fatty acid concentration of the medium. These results suggest that, at least for oleic acid, extracellular fatty acids are not utilized directly for VLDL assembly, but first enter a temporary intracellular storage pool of triacylglycerol, which is the immediate precursor of secreted triacylglycerol. The size of this pool then determines the rate of secretion of VLDL triacylglycerol apoB. Ketogenesis, on the other hand, relies mainly on the direct utilization of extracellular fatty acids. |
| Databáze: | OpenAIRE |
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