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The conversion rate to docosahexaenoic acid from alpha‐linolenic acid in rat liver: Effects of n‐3 PUFA deprivation
Author(s) -
Igarashi Miki,
DeMar James C,
Ma Kaizong,
Chang Lisa,
Bell Jane M,
Rapoport Stanley I
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a339
Subject(s) - docosahexaenoic acid , polyunsaturated fatty acid , medicine , endocrinology , phospholipid , chemistry , alpha linolenic acid , hepatocyte , linolenic acid , biochemistry , fatty acid , biology , linoleic acid , in vitro , membrane
We quantified the synthesis‐conversion rate to docosahexaenoic acid (DHA, 22:6n‐3) from α‐linolenic acid (α‐LNA, 18:3n‐3) in the liver of unanesthetized male rats fed n‐3 PUFA adequate (4.6% α‐LNA and no DHA) and deprived (0.2% α‐LNA, no DHA) diets. These rays were infused [1‐ 14 C] α‐LNA intravenously, and arterial plasma was collected until liver was microwaved at 5 min. Total DHA content was decreased by 92% in the deprived liver and plasma. Deprivation didn't affect incorporation coefficients of α‐LNA into stable lipids, but increased synthesis‐incorporation coefficients of DHA from α‐LNA by 6.6, 8.4 and 2.3 fold in triacylglycerol, phospholipid and cholesteryl ester, respectively, since the deprivation upregulated liver DHA synthesis. Assuming that synthesized DHA eventually would be secreted within lipoproteins, we calculated liver DHA secretion rates of 2.19 and 0.82 μmol/day in the adequate and deprived rats, respectively. Comparisons with published data suggest that the former rate is sufficient to maintain a normal brain DHA content and 6‐hold of brain DHA consumption (0.38 μmol/day), whereas the latter rate corresponds to a reduced brain DHA content and 10‐hold of brain DHA consumption (0.087 μmol/day). These results provide the conversion rates of α‐LNA secreted DHA by rat liver, and they are related with brain DHA consumption rates under n‐3 PUFA adequate and deficient dietary conditions.