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Docosahexaenoic acid synthesis from alpha-linolenic acid by rat brain is unaffected by dietary n-3 PUFA deprivation.
J Lipid Res. 2007 May; 48(5):1150-8.JL

Abstract

Rates of conversion of alpha-linolenic acid (alpha-LNA, 18:3n-3) to docosahexaenoic acid (DHA, 22:6n-3) by the mammalian brain and the brain's ability to upregulate these rates during dietary deprivation of n-3 polyunsaturated fatty acids (PUFAs) are unknown. To answer these questions, we measured conversion coefficients and rates in post-weaning rats fed an n-3 PUFA deficient (0.2% alpha-LNA of total fatty acids, no DHA) or adequate (4.6% alpha-LNA, no DHA) diet for 15 weeks. Unanesthetized rats in each group were infused intravenously with [1-(14)C]alpha-LNA, and their arterial plasma and microwaved brains collected at 5 minutes were analyzed. The deficient compared with adequate diet reduced brain DHA by 37% and increased brain arachidonic (20:4n-6) and docosapentaenoic (22:5n-6) acids. Only 1% of plasma [1-(14)C]alpha-LNA entering brain was converted to DHA with the adequate diet, and conversion coefficients of alpha-LNA to DHA were unchanged by the deficient diet. In summary, the brain's ability to synthesize DHA from alpha-LNA is very low and is not altered by n-3 PUFA deprivation. Because the liver's reported ability is much higher, and can be upregulated by the deficient diet, DHA converted by the liver from circulating alphaLNA is the source of the brain's DHA when DHA is not in the diet.

Authors+Show Affiliations

Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA. mikii@mail.nih.govNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

17277380

Citation

Igarashi, Miki, et al. "Docosahexaenoic Acid Synthesis From Alpha-linolenic Acid By Rat Brain Is Unaffected By Dietary N-3 PUFA Deprivation." Journal of Lipid Research, vol. 48, no. 5, 2007, pp. 1150-8.
Igarashi M, DeMar JC, Ma K, et al. Docosahexaenoic acid synthesis from alpha-linolenic acid by rat brain is unaffected by dietary n-3 PUFA deprivation. J Lipid Res. 2007;48(5):1150-8.
Igarashi, M., DeMar, J. C., Ma, K., Chang, L., Bell, J. M., & Rapoport, S. I. (2007). Docosahexaenoic acid synthesis from alpha-linolenic acid by rat brain is unaffected by dietary n-3 PUFA deprivation. Journal of Lipid Research, 48(5), 1150-8.
Igarashi M, et al. Docosahexaenoic Acid Synthesis From Alpha-linolenic Acid By Rat Brain Is Unaffected By Dietary N-3 PUFA Deprivation. J Lipid Res. 2007;48(5):1150-8. PubMed PMID: 17277380.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Docosahexaenoic acid synthesis from alpha-linolenic acid by rat brain is unaffected by dietary n-3 PUFA deprivation. AU - Igarashi,Miki, AU - DeMar,James C,Jr AU - Ma,Kaizong, AU - Chang,Lisa, AU - Bell,Jane M, AU - Rapoport,Stanley I, Y1 - 2007/02/04/ PY - 2007/2/6/pubmed PY - 2007/6/23/medline PY - 2007/2/6/entrez SP - 1150 EP - 8 JF - Journal of lipid research JO - J Lipid Res VL - 48 IS - 5 N2 - Rates of conversion of alpha-linolenic acid (alpha-LNA, 18:3n-3) to docosahexaenoic acid (DHA, 22:6n-3) by the mammalian brain and the brain's ability to upregulate these rates during dietary deprivation of n-3 polyunsaturated fatty acids (PUFAs) are unknown. To answer these questions, we measured conversion coefficients and rates in post-weaning rats fed an n-3 PUFA deficient (0.2% alpha-LNA of total fatty acids, no DHA) or adequate (4.6% alpha-LNA, no DHA) diet for 15 weeks. Unanesthetized rats in each group were infused intravenously with [1-(14)C]alpha-LNA, and their arterial plasma and microwaved brains collected at 5 minutes were analyzed. The deficient compared with adequate diet reduced brain DHA by 37% and increased brain arachidonic (20:4n-6) and docosapentaenoic (22:5n-6) acids. Only 1% of plasma [1-(14)C]alpha-LNA entering brain was converted to DHA with the adequate diet, and conversion coefficients of alpha-LNA to DHA were unchanged by the deficient diet. In summary, the brain's ability to synthesize DHA from alpha-LNA is very low and is not altered by n-3 PUFA deprivation. Because the liver's reported ability is much higher, and can be upregulated by the deficient diet, DHA converted by the liver from circulating alphaLNA is the source of the brain's DHA when DHA is not in the diet. SN - 0022-2275 UR - https://www.unboundmedicine.com/medline/citation/17277380/Docosahexaenoic_acid_synthesis_from_alpha_linolenic_acid_by_rat_brain_is_unaffected_by_dietary_n_3_PUFA_deprivation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2275(20)43561-8 DB - PRIME DP - Unbound Medicine ER -