Metabolism of long-chain polyunsaturated fatty acids in isolated cardiac myocytes.
The uptake and integrated intracellular metabolism of (n - 6) and (n - 3) polyunsaturated fatty acids was studied in isolated rat cardiac myocytes and in the perfused heart. Labeled linolenic acid (18:3(n - 3)) uptake and its subsequent metabolism into carbon dioxide as well as acylation into lipids was nonsaturable over a substrate range of 0.02 to 0.4 mM. [1-14C]Linoleic acid (18:2(n - 6)), dihomo-gamma-linolenic acid (20:3(n - 6)) and arachidonic acid (20:4(n - 6)) were transported into myocytes at rates similar to those for linolenic acid. Conversely both [1-14C]-gamma-linolenic acid (18:3(n - 6)) and eicosapentaenoic acid (20:5(n - 3)) were taken up at a slower rate. Oxidation of 18:3(n - 6) was 4-5-fold greater when compared with C18-C20 polyunsaturated fatty acids. When myocytes were incubated with labeled 18:2(n - 6), 18:3(n - 6), 18:3(n - 3), 20:4(n - 6) or 20:5(n - 3), it was not possible to detect any desaturation or chain-elongation products. Identical results were obtained when hearts were perfused with 1-14C-labeled linoleic acid.
Hagve
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Department of Physiological Chemistry, College of Medicine, Ohio State University, Columbus 43210.
Sprecher
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D000818:Animals; D005231:Fatty Acids, Unsaturated / Q000378:metabolism* / Q000493:pharmacokinetics; D008042:Linolenic Acids / Q000493:pharmacokinetics; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship; D013997:Time Factors; D017962:alpha-Linolenic Acid
D005231:Fatty Acids, Unsaturated; D008042:Linolenic Acids; D017962:alpha-Linolenic Acid