title: Trans-membrane uptake and intracellular metabolism of fatty acids in Atlantic salmon (Salmo salar L.) hepatocytes.
abstract: To elucidate if the trans-membrane uptake of fatty acids is protein-mediated, the uptake of oleic acid (18:1n-9), linoleic acid (18:2n-6), alpha-linolenic acid (18:3n-3), eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) was investigated in vitro in Atlantic salmon (Salmo salar L.) primary hepatocytes. Firstly, optimal fatty acid incubation time and concentration were established for trans-membrane 18:n-9 uptake. Based on saturation kinetics, a 2-h incubation time and 37.5 muM were used for the following experiments. Secondly, in order to identify whether trans-membrane fatty acid uptake in hepatocytes was mainly passive or protein mediated, hepatocytes were pre-incubated with membrane protein inhibitors followed by 2 h of incubation with [1-(14)C] labelled 18:1n-9, 18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3. Fatty acid uptake into hepatocytes was highest with 20:5n-3 and 22:6n-3 and lowest with 18:1n-9. Phloretin was the most potent fatty acid uptake inhibitor, inhibiting uptake in the following order: 20:5n-3 > 18:3n-3 = 22:6n-3 > 18:2n-6 > 18:1n-9. The uptake of FA in Atlantic salmon hepatocytes seem to be due to both saturable and inhibitable protein mediated uptake, as well as passive uptake processes with more unsaturated and long fatty acids (20:n-3 > 22:6n-3 = 18:3n-3 > 18:2n-6) being more dependent on membrane protein mediated uptake compared to 18:1n-9.
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi, China.
authors.forename: Jishu
authors.initials: J
authors.lastname: Zhou
authors.forename: Ingunn
authors.initials: I
authors.lastname: Stubhaug
authors.forename: Bente E
authors.initials: BE
authors.lastname: Torstensen
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D005227:Fatty Acids / Q000378:metabolism* / Q000493:pharmacokinetics; D005395:Fish Oils / Q000493:pharmacokinetics / Q000494:pharmacology; D022781:Hepatocytes / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism*; D050356:Lipid Metabolism / Q000502:physiology; D008660:Metabolism / Q000502:physiology; D010938:Plant Oils / Q000493:pharmacokinetics / Q000494:pharmacology; D020317:Salmo salar / Q000378:metabolism*; D013997:Time Factors; D017962:alpha-Linolenic Acid / Q000378:metabolism / Q000493:pharmacokinetics
chemical_list: D005227:Fatty Acids; D005395:Fish Oils; D010938:Plant Oils; D017962:alpha-Linolenic Acid