Metabolic fate of long-chain unsaturated fatty acids and their effects on palmitic acid metabolism and gluconeogenesis in bovine hepatocytes.
The objectives were to determine the metabolic fate of different long-chain fatty acids, and their effects on palmitic acid metabolism and gluconeogenesis in bovine hepatocytes. Hepatocytes were isolated from four ruminating calves and exposed in suspension for 3 h to one of the following treatments: 1 mM palmitic acid (1C16), 2 mM palmitic acid (2C16), or 1 mM palmitic acid plus either 1 mM oleic (C18:1), linoleic (C18:2), linolenic (C18:3), eicosapentaenoic (C20:5), or docosahexaenoic acid (C22:6). Oxidation of [1-(14)C]palmitic acid or one of the [1-(14)C]-labeled treatment fatty acids to CO2 or incorporation into cellular triglycerides (TG), phospholipids, cholesterol, and cholesterol esters were measured. Rates of oxidation to CO2 were 3- to 4-fold higher for C22:6 than for other fatty acids, with the exception of C20:5, which had intermediate rates of oxidation to CO2. In general, treatments 2C16 and C18:1 yielded the highest rates of incorporation into most cellular lipids, whereas the polyunsaturated fatty acids were poor substrates for incorporation into cellular lipids. The most pronounced change was a large reduction of polyunsaturated fatty acid incorporation into cellular TG compared to 1C16, 2C16, and C18:1. The unsaturated fatty acids also influenced palmitic acid metabolism. The addition of C20:5 yielded the highest rates of palmitic acid oxidation to CO2 followed by addition of C18:1 and C22:6. Treatments containing polyunsaturated fatty acids decreased palmitic acid metabolism to TG and total cellular lipids compared with treatments 2C16 and C18:1. Rates of gluconeogenesis from propionate were significantly higher for the treatment containing C18:1. Long-chain fatty acids vary in their routes of metabolism and influence palmitic acid metabolism and gluconeogenesis in bovine hepatocytes.
D000818:Animals; D002417:Cattle / Q000378:metabolism*; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000378:metabolism* / Q000494:pharmacology*; D005943:Gluconeogenesis / Q000187:drug effects*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D019787:Linoleic Acid / Q000494:pharmacology; D008297:Male; D019301:Oleic Acid / Q000494:pharmacology; D010084:Oxidation-Reduction; D019308:Palmitic Acid / Q000378:metabolism* / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism; D011422:Propionates / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism; D017962:alpha-Linolenic Acid / Q000494:pharmacology
D002788:Cholesterol Esters; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D011422:Propionates; D014280:Triglycerides; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D019301:Oleic Acid; D019308:Palmitic Acid; D002784:Cholesterol; D019787:Linoleic Acid; D015118:Eicosapentaenoic Acid; C029658:propionic acid