AGE

, Volume 35, Issue 3, pp 597–608

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

  • Fei Gao
  • Ameer Y. Taha
  • Kaizong Ma
  • Lisa Chang
  • Dale Kiesewetter
  • Stanley I. Rapoport
Article

DOI: 10.1007/s11357-012-9390-1

Cite this article as:
Gao, F., Taha, A.Y., Ma, K. et al. AGE (2013) 35: 597. doi:10.1007/s11357-012-9390-1

Abstract

Docosahexaenoic acid (DHA, 22:6n-3), an n-3 polyunsaturated fatty acid (PUFA) found at high concentrations in brain and retina and critical to their function, can be obtained from fish products or be synthesized from circulating α-linolenic acid (α-LNA, 18:3n-3) mainly in the liver. With aging, liver synthetic enzymes are reported reduced or unchanged in the rat. To test whether liver synthesis-secretion of DHA from α-LNA changes with age, we measured whole-body DHA conversion coefficients and rates in unanesthetized adult male Fischer-344 rats aged 10, 20, or 30 months, fed an eicosapentaenoic acid (EPA, 20:5n-3)- and DHA-containing diet. Unesterified [U- 13 C]α-LNA bound to albumin was infused intravenously for 2 h, while [13 C]-esterified n-3 PUFAs were measured in arterial plasma, as were unlabeled unesterified and esterified PUFA concentrations. Plasma unesterified n-3 PUFA concentrations declined with age, but esterified n-3 PUFA concentrations did not change significantly. Calculated conversion coefficients were not changed significantly with age, whereas synthesis-secretion rates (product of conversion coefficient and unesterified plasma α-LNA concentration) of esterified DHA and n-3 DPA were reduced. Turnovers of esterified n-3 PUFAs in plasma decreased with age, whereas half-lives increased. The results suggest that hepatic capacity to synthesize DHA and other n-3 PUFAs from circulating α-LNA is maintained with age in the rat, but that reduced plasma α-LNA availability reduces net synthesis-secretion. As unesterified plasma DHA is the form that is incorporated preferentially into brain phospholipid, its reduced synthesis may be deleterious to brain function in aged rats.

Keywords

LiverSynthesis-secretion rateConversionAgingAgeMetabolismAlpha-linolenic acidn-3 Polyunsaturated fatty acids (n-3 PUFAs)Docosahexaenoic acid (DHA)Lipid

Abbreviations

α-LNA

α-Linolenic acid

AA

Arachidonic acid

DHA

Docosahexaenoic acid

DPA

Docosapentaenoic acid

EPA

Eicosapentaenoic acid

LA

Linoleic acid

PFB

Pentafluorobenzyl

PUFA

Polyunsaturated fatty acid

Copyright information

© American Aging Association 2012

Authors and Affiliations

  • Fei Gao
    • 1
    • 3
  • Ameer Y. Taha
    • 1
  • Kaizong Ma
    • 1
  • Lisa Chang
    • 1
  • Dale Kiesewetter
    • 2
  • Stanley I. Rapoport
    • 1
  1. 1.Brain Physiology and Metabolism Section, National Institute on AgingNational Institutes of HealthBethesdaUSA
  2. 2.Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and BioengineeringNational Institutes of HealthBethesdaUSA
  3. 3.Center for Experimental Therapeutics and Reperfusion InjuryBrigham and Women’s Hospital, Harvard Medical SchoolBostonUSA