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7.3C: Brain Macronutrient Metabolism

  • Page ID
    1503
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    Fatty acid breakdown does not occur to any great extent in the brain because of the low activity of an enzyme in the beta-oxidation pathway limits the activity of this pathway1. Compared to the extrahepatic tissues as a whole, in the brain the following pathways are not performed or are not important:

    • Glycogen synthesis and breakdown
    • Lactate synthesis
    • Fatty acid synthesis and breakdown
    • Triglyceride synthesis and breakdown
    • Protein synthesis and breakdown

    These pathways are crossed out on the figure below.

    Figure 7.331 .png

    Figure 7.331 The metabolic pathways that are not performed or important in the brain compared to extrahepatic tissues as a whole are crossed out2

    Fatty acid breakdown does not occur to any great extent in the brain because low activity of an enzyme in the beta-oxidation pathway limits the activity of this pathway2. By removing those pathways the only pathways left are:

    • Glycolysis
    • Ketone body breakdown

    Figure 7.332.png

    Figure 7.332 Brain metabolic capability1

    Thus, due to its limited metabolic capabilities, the brain needs to receive either glucose or ketone bodies to use as an energy source.

    References & Links

    1. Yang SY, He XY, Schulz H (1987) Fatty acid oxidation in rat brain is limited by the low activity of 3-ketoacyl-coenzyme A thiolase. J BIol Chem 262 (27): 13027-13032.
    2. en.Wikipedia.org/wiki/File:CellRespiration.svg

    This page titled 7.3C: Brain Macronutrient Metabolism is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Brian Lindshield via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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