Abstract
We summarize here the evidence indicating that carbon from α-linolenate and linoleate is readily recycled into newly synthesized lipids. This pathway consumes the majority of these fatty acids that is not β-oxidized as a fuel. Docosahexaenoate undergoes less β-oxidation and carbon recycling than do α-linolenate or linoleate, but is it still actively metabolized by this pathway? Among polyunsaturates, arachidonate appears to undergo the least β-oxidation and carbon recycling, an observation that may help account for the resistance of brain membranes to loss of arachidonate during dietary deficiency of n−6 polyunsaturates. Preliminary evidence suggests that de novo lipid synthesis consumes carbon from α-linolenate and linoleate in preference to palmitate, but this merits systematic study. Active β-oxidation and carbon recycling of 18-carbon polyunsaturates does not diminish the importance of being able to convert α-linolenate and linoleate to long-chain polyunsaturates but suggests that a broad perspective is required in studying the metabolism of polyunsaturates in general and α-linolenate and linoleate in particular.
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Abbreviations
- ALA:
-
α-linolenate
- DHA:
-
docosahexaenoate
- HMG:
-
3-hydroxy-3-methylglutaryl
- LA:
-
linoleate
- LC-PUFA:
-
long-chain polyunsaturated fatty acids
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Cunnane, S.C., Ryan, M.A., Nadeau, C.R. et al. Why is carbon from some polyunsaturates extensively recycled into lipid synthesis?. Lipids 38, 477–484 (2003). https://doi.org/10.1007/s11745-003-1087-8
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DOI: https://doi.org/10.1007/s11745-003-1087-8