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Can the rat liver maintain normal brain DHA metabolism in the absence of dietary DHA?
Prostaglandins Leukot Essent Fatty Acids. 2009 Aug-Sep; 81(2-3):119-23.PL

Abstract

BACKGROUND

Docosahexaenoic acid (DHA) is required for normal brain function. The concentration of DHA in the brain depends on both diet and liver metabolism.

OBJECTIVE

To determine rat brain DHA concentration and consumption in relation to dietary n-3 (omega-3) polyunsaturated fatty acid (PUFA) content and liver secretion of DHA derived from circulating alpha-linolenic acid (alpha-LNA).

DESIGN

Following weaning, male rats were fed for 15 weeks either: (1) a diet with a high DHA and alpha-LNA content, (2) an n-3 PUFA "adequate" diet containing 4.6% alpha-LNA but no DHA, or (3) an n-3 PUFA "deficient" diet containing 0.2% alpha-LNA and no DHA. Brain DHA consumption rates were measured following intravenous infusion in unanesthetized rats of [1-14C]DHA, whereas liver and brain DHA synthesis rates were measured by infusing [1-14C]alpha-LNA.

RESULTS

Brain DHA concentrations equaled 17.6, 11.4 and 7.14 microm/g in rats on diets 1, 2 and 3, respectively. With each diet, the rate of brain DHA synthesis from alpha-LNA was much less than the brain DHA consumption rate, whereas the liver synthesis-secretion rate was 5-10 fold higher. Higher elongase 2 and 5 and desaturase Delta5 and Delta6 activities in liver than in brain accounted for the higher liver DHA synthesis rates. Furthermore, these enzymes were transcriptionally upregulated in liver but not in brain of rats fed the deficient diet.

CONCLUSIONS

While DHA is essential to normal brain function, this need might be covered by dietary alpha-LNA when liver metabolic conversion machinery is intact and the diet has a high alpha-LNA content.

Links

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Authors+Show Affiliations

Rapoport SI
Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Building 9, Room 1S128, 9000 Rockville Pike, Bethesda, MD 20892, USA. sir@helix.nih.gov
Igarashi M
No affiliation info available

MeSH

AnimalsBrainDietDocosahexaenoic AcidsFatty Acids, Omega-3Fatty Acids, UnsaturatedLiverMaleRatsalpha-Linolenic Acid

Pub Type(s)

Journal Article
Research Support, N.I.H., Intramural

Language

eng

PubMed ID

19540098

Citation

Rapoport, Stanley I., and Miki Igarashi. "Can the Rat Liver Maintain Normal Brain DHA Metabolism in the Absence of Dietary DHA?" Prostaglandins, Leukotrienes, and Essential Fatty Acids, vol. 81, no. 2-3, 2009, pp. 119-23.
Rapoport SI, Igarashi M. Can the rat liver maintain normal brain DHA metabolism in the absence of dietary DHA? Prostaglandins Leukot Essent Fatty Acids. 2009;81(2-3):119-23.
Rapoport, S. I., & Igarashi, M. (2009). Can the rat liver maintain normal brain DHA metabolism in the absence of dietary DHA? Prostaglandins, Leukotrienes, and Essential Fatty Acids, 81(2-3), 119-23. https://doi.org/10.1016/j.plefa.2009.05.021
Rapoport SI, Igarashi M. Can the Rat Liver Maintain Normal Brain DHA Metabolism in the Absence of Dietary DHA. Prostaglandins Leukot Essent Fatty Acids. 2009 Aug-Sep;81(2-3):119-23. PubMed PMID: 19540098.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Can the rat liver maintain normal brain DHA metabolism in the absence of dietary DHA? AU - Rapoport,Stanley I, AU - Igarashi,Miki, Y1 - 2009/06/18/ PY - 2009/6/23/entrez PY - 2009/6/23/pubmed PY - 2009/12/16/medline SP - 119 EP - 23 JF - Prostaglandins, leukotrienes, and essential fatty acids JO - Prostaglandins Leukot Essent Fatty Acids VL - 81 IS - 2-3 N2 - BACKGROUND: Docosahexaenoic acid (DHA) is required for normal brain function. The concentration of DHA in the brain depends on both diet and liver metabolism. OBJECTIVE: To determine rat brain DHA concentration and consumption in relation to dietary n-3 (omega-3) polyunsaturated fatty acid (PUFA) content and liver secretion of DHA derived from circulating alpha-linolenic acid (alpha-LNA). DESIGN: Following weaning, male rats were fed for 15 weeks either: (1) a diet with a high DHA and alpha-LNA content, (2) an n-3 PUFA "adequate" diet containing 4.6% alpha-LNA but no DHA, or (3) an n-3 PUFA "deficient" diet containing 0.2% alpha-LNA and no DHA. Brain DHA consumption rates were measured following intravenous infusion in unanesthetized rats of [1-14C]DHA, whereas liver and brain DHA synthesis rates were measured by infusing [1-14C]alpha-LNA. RESULTS: Brain DHA concentrations equaled 17.6, 11.4 and 7.14 microm/g in rats on diets 1, 2 and 3, respectively. With each diet, the rate of brain DHA synthesis from alpha-LNA was much less than the brain DHA consumption rate, whereas the liver synthesis-secretion rate was 5-10 fold higher. Higher elongase 2 and 5 and desaturase Delta5 and Delta6 activities in liver than in brain accounted for the higher liver DHA synthesis rates. Furthermore, these enzymes were transcriptionally upregulated in liver but not in brain of rats fed the deficient diet. CONCLUSIONS: While DHA is essential to normal brain function, this need might be covered by dietary alpha-LNA when liver metabolic conversion machinery is intact and the diet has a high alpha-LNA content. SN - 1532-2823 UR - https://www.unboundmedicine.com/medline/citation/19540098/Can_the_rat_liver_maintain_normal_brain_DHA_metabolism_in_the_absence_of_dietary_DHA L2 - https://linkinghub.elsevier.com/retrieve/pii/S0952-3278(09)00099-4 DB - PRIME DP - Unbound Medicine ER -