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Rat heart cannot synthesize docosahexaenoic acid from circulating alpha-linolenic acid because it lacks elongase-2.
J Lipid Res. 2008 Aug; 49(8):1735-45.JL

Abstract

The extent to which the heart can convert alpha-linolenic acid (alpha-LNA, 18:3n-3) to longer chain n-3 PUFAs is not known. Conversion rates can be measured in vivo using radiolabeled alpha-LNA and a kinetic fatty acid model. [1-(14)C]alpha-LNA was infused intravenously for 5 min in unanesthetized rats that had been fed an n-3 PUFA-adequate [4.6% alpha-LNA, no docosahexaenoic acid (DHA, 22:6n-3)] or n-3 PUFA-deficient diet (0.2% alpha-LNA, nor DHA) for 15 weeks after weaning. Arterial plasma was sampled, as was the heart after high-energy microwaving. Rates of conversion of alpha-LNA to longer chain n-3 PUFAs were low, and DHA was not synthesized at all in the heart. Most alpha-LNA within the heart had been beta-oxidized. In deprived compared with adequate rats, DHA concentrations in plasma and heart were both reduced by >90%, whereas heart and plasma levels of docosapentaenoic acid (DPAn-6, 22:5n-6) were elevated. Dietary deprivation did not affect cardiac mRNA levels of elongase-5 or desaturases Delta6 and Delta5, but elongase-2 mRNA could not be detected. In summary, the rat heart does not synthesize DHA from alpha-LNA, owing to the absence of elongase-2, but must obtain its DHA entirely from plasma. Dietary n-3 PUFA deprivation markedly reduces heart DHA and increases heart DPAn-6, which may make the heart vulnerable to different insults.

Authors+Show Affiliations

Brain Physiology and Metabolism Section, National Institute on Aging, NIH, Bethesda, MD 20892, USA. mikii@mail.nih.govNo 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

18456640

Citation

Igarashi, Miki, et al. "Rat Heart Cannot Synthesize Docosahexaenoic Acid From Circulating Alpha-linolenic Acid Because It Lacks Elongase-2." Journal of Lipid Research, vol. 49, no. 8, 2008, pp. 1735-45.
Igarashi M, Ma K, Chang L, et al. Rat heart cannot synthesize docosahexaenoic acid from circulating alpha-linolenic acid because it lacks elongase-2. J Lipid Res. 2008;49(8):1735-45.
Igarashi, M., Ma, K., Chang, L., Bell, J. M., & Rapoport, S. I. (2008). Rat heart cannot synthesize docosahexaenoic acid from circulating alpha-linolenic acid because it lacks elongase-2. Journal of Lipid Research, 49(8), 1735-45. https://doi.org/10.1194/jlr.M800093-JLR200
Igarashi M, et al. Rat Heart Cannot Synthesize Docosahexaenoic Acid From Circulating Alpha-linolenic Acid Because It Lacks Elongase-2. J Lipid Res. 2008;49(8):1735-45. PubMed PMID: 18456640.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Rat heart cannot synthesize docosahexaenoic acid from circulating alpha-linolenic acid because it lacks elongase-2. AU - Igarashi,Miki, AU - Ma,Kaizong, AU - Chang,Lisa, AU - Bell,Jane M, AU - Rapoport,Stanley I, Y1 - 2008/05/01/ PY - 2008/5/6/pubmed PY - 2008/9/13/medline PY - 2008/5/6/entrez SP - 1735 EP - 45 JF - Journal of lipid research JO - J Lipid Res VL - 49 IS - 8 N2 - The extent to which the heart can convert alpha-linolenic acid (alpha-LNA, 18:3n-3) to longer chain n-3 PUFAs is not known. Conversion rates can be measured in vivo using radiolabeled alpha-LNA and a kinetic fatty acid model. [1-(14)C]alpha-LNA was infused intravenously for 5 min in unanesthetized rats that had been fed an n-3 PUFA-adequate [4.6% alpha-LNA, no docosahexaenoic acid (DHA, 22:6n-3)] or n-3 PUFA-deficient diet (0.2% alpha-LNA, nor DHA) for 15 weeks after weaning. Arterial plasma was sampled, as was the heart after high-energy microwaving. Rates of conversion of alpha-LNA to longer chain n-3 PUFAs were low, and DHA was not synthesized at all in the heart. Most alpha-LNA within the heart had been beta-oxidized. In deprived compared with adequate rats, DHA concentrations in plasma and heart were both reduced by >90%, whereas heart and plasma levels of docosapentaenoic acid (DPAn-6, 22:5n-6) were elevated. Dietary deprivation did not affect cardiac mRNA levels of elongase-5 or desaturases Delta6 and Delta5, but elongase-2 mRNA could not be detected. In summary, the rat heart does not synthesize DHA from alpha-LNA, owing to the absence of elongase-2, but must obtain its DHA entirely from plasma. Dietary n-3 PUFA deprivation markedly reduces heart DHA and increases heart DPAn-6, which may make the heart vulnerable to different insults. SN - 0022-2275 UR - https://www.unboundmedicine.com/medline/citation/18456640/Rat_heart_cannot_synthesize_docosahexaenoic_acid_from_circulating_alpha_linolenic_acid_because_it_lacks_elongase_2_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2275(20)34692-7 DB - PRIME DP - Unbound Medicine ER -