title: β-oxidation and rapid metabolism, but not uptake regulate brain eicosapentaenoic acid levels.
abstract: The brain has a unique polyunsaturated fatty acid composition, with high levels of arachidonic and docosahexaenoic acids (DHA) while levels of eicosapentaenoic acid (EPA) are several orders of magnitude lower. As evidence accumulated that fatty acid entry into the brain was not selective and, in fact, that DHA and EPA enter the brain at similar rates, new mechanisms were required to explain their large concentration differences in the brain. Here we summarize recent research demonstrating that EPA is rapidly and extensively β-oxidized upon entry into the brain. Although the ATP generated from the β-oxidation of EPA is low compared to the use of glucose, fatty acid β-oxidation may serve to regulate brain fatty acid levels in the absence of selective transportation. Furthermore, when β-oxidation of EPA is blocked, desaturation of EPA increases and Land׳s recycling decreases to maintain low EPA levels.
authors.affiliation: Department of Nutritional Sciences, University of Toronto, Fitzgerald Building, 150 College St. Room 306, Ontario, Toronto, M5S 3E2 Canada.
authors.forename: Chuck T
authors.initials: CT
authors.lastname: Chen
authors.affiliation: Department of Nutritional Sciences, University of Toronto, Fitzgerald Building, 150 College St. Room 306, Ontario, Toronto, M5S 3E2 Canada. Electronic address: richard.bazinet@utoronto.ca.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Bazinet
mesh_terms: D000818:Animals; D001692:Biological Transport; D001921:Brain / Q000378:metabolism*; D015118:Eicosapentaenoic Acid / Q000378:metabolism*; D004951:Esterification; D006801:Humans; D050356:Lipid Metabolism; D010084:Oxidation-Reduction
chemical_list: D015118:Eicosapentaenoic Acid