Adipose hormone-sensitive lipase preferentially releases polyunsaturated fatty acids from triglycerides.
Rat adipose hormone-sensitive lipase-mediated release of fatty acids from triglycerides was studied in three model systems: i) cultured preadipocytes containing polyunsaturated fatty acid-enriched triglyceride; ii) perfused epididymal fat pads; and iii) in vitro incubations of crude preparations of hormone-sensitive lipase with synthetic triglyceride-analogues as substrates. We found that cultured preadipocytes challenged with 10 microM norepinephrine tended to release more omega 6 and omega 3 polyunsaturated fatty acids than saturated fatty acids. Fat pads perfused with 10 microM norepinephrine preferentially released arachidonate and alpha-linolenate but tended to retain oleate and linoleate. Finally, crude preparations of hormone-sensitive lipase released from the triglyceride-analogue substrates alpha-linolenate twice as fast as oleate. We conclude that rat adipose hormone-sensitive lipase preferentially releases polyunsaturated fatty acids from triglycerides. We suggest that this may be a mechanism by which these fatty acids are kept from being trapped in fat depots and maintained in the circulation.
Department of Nutrition, Université de Montréal, Québec, Canada.
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D000273:Adipose Tissue / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002478:Cells, Cultured; D004822:Epididymis / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D066298:In Vitro Techniques; D008042:Linolenic Acids / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000378:metabolism; D002787:Sterol Esterase / Q000187:drug effects / Q000378:metabolism*; D013379:Substrate Specificity; D014280:Triglycerides / Q000378:metabolism*; D017962:alpha-Linolenic Acid
D005231:Fatty Acids, Unsaturated; D008042:Linolenic Acids; D009829:Oleic Acids; D014280:Triglycerides; D017962:alpha-Linolenic Acid; D016718:Arachidonic Acid; D019301:Oleic Acid; D002787:Sterol Esterase; D009638:Norepinephrine