Docosahexaenoic acid synthesis from α-linolenic acid by rat brain is unaffected by dietary n-3 PUFA deprivation

Igarashi, Miki; DeMar, James C.; Ma, Kaizong; Chang, Lisa; Bell, Jane M.; Rapoport, Stanley I.

doi:10.1194/jlr.m600549-jlr200

Cited by 138 publications

(138 citation statements)

References 55 publications

Supporting

Mentioning

121

Contrasting

Unclassified

Order By: Relevance

“…DHA may be obtained directly from dietary sources, such as fish or fish products, or it can be synthesized from its nutritionally essential plant-derived precursor, α-linolenic acid (18:3n-3, α-LNA), through a series of elongation and desaturation steps (Sprecher 2000). The major site of DHA synthesis is the liver, whereas brain or heart synthesis is much less (Scott and Bazan 1989;Demar et al 2005;Igarashi et al 2007;Igarashi et al 2008;Rapoport et al 2010).…”

mentioning

confidence: 99%

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Gao

Taha

et al. 2012

AGE

Self Cite

View full text Add to dashboard Cite

Docosahexaenoic acid (DHA,, 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 DHAcontaining 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.

show abstract

mentioning

confidence: 99%

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Gao

Taha

et al. 2012

AGE

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although high ALA intake drastically increased the ALA content in plasma lipids (an increase of the proportion from 6 1% to 10%), which is a reflection of the increase of ALA content in liver (Table 4), the ALA and DHA contents in frontal cortex and hippocampus did not increase (Tables 5 and 6). Other studies in rat brain showed that ALA after uptake from the circulation across the blood-brain barrier will be mainly oxidized and only a small fraction is converted to DHA (DeMar et al, 2005;Igarashi et al, 2007b). The activity of desaturation and elongation are higher in liver in comparison with brain (Igarashi et al, 2007a).…”

Section: Brainmentioning

confidence: 94%

Linoleic and α-linolenic acid as precursor and inhibitor for the synthesis of long-chain polyunsaturated fatty acids in liver and brain of growing pigs

Smink

Gerrits

Gloaguen

et al. 2012

Animal

View full text Add to dashboard Cite

Studies suggested that in human adults, linoleic acid (LA) inhibits the biosynthesis of n-3 long-chain polyunsaturated fatty acids (LC-PUFA), but their effects in growing subjects are largely unknown. We used growing pigs as a model to investigate whether high LA intake affects the conversion of n-3 LC-PUFA by determining fatty acid composition and mRNA levels of D5-and D6 desaturase and elongase 2 and -5 in liver and brain. In a 2 3 2 factorial arrangement, 32 gilts from eight litters were assigned to one of the four dietary treatments, varying in LA and a-linolenic acid (ALA) intakes. Low ALA and LA intakes were 0.15 and 1.31, and high ALA and LA intakes were 1.48 and 2.65 g/kg BW 0.75 per day, respectively. LA intake increased arachidonic acid (ARA) in liver. ALA intake increased eicosapentaenoic acid (EPA) concentrations, but decreased docosahexaenoic acid (DHA) (all P , 0.01) in liver. Competition between the n-3 and n-6 LC-PUFA biosynthetic pathways was evidenced by reductions of ARA (.40%) at high ALA intakes. Concentration of EPA (.35%) and DHA (.20%) was decreased by high LA intake (all P , 0.001). Liver mRNA levels of D5-and D6 desaturase were increased by LA, and that of elongase 2 by both ALA and LA intakes. In contrast, brain DHA was virtually unaffected by dietary LA and ALA. Generally, dietary LA inhibited the biosynthesis of n-3 LC-PUFA in liver. ALA strongly affects the conversion of both hepatic n-3 and n-6 LC-PUFA. DHA levels in brain were irresponsive to these diets. Apart from D6 desaturase, elongase 2 may be a rate-limiting enzyme in the formation of DHA.

show abstract

“…Small fractions of LA and alpha-linolenic acid in the brain are converted to arachidonic acid (20:4n-6, AA) and docosahexaenoic acid (22:6n-3, DHA), respectively [41,42]. Besides, the alternations in the level of LA, the levels of dihomo-gamma-linolenic acid (20:3n-6) remained unchanged among all experimental groups.…”

Section: Discussionmentioning

confidence: 81%

Effects Of Dietary Supplementation With A Mixture Of Buckwheat Leaf And Flower On Fatty Acid Composition Of Rat Brain Phospholipids

et al. 2015

View full text Add to dashboard Cite

The aim of our study was to stablish the possible alternations in fatty acid composition of brain phospholipids in rats on a standard and high-fat diet supplemented with buckwheat leaf and fl ower mixture (BLF) and subsequent possible benefi cial effects of BLF. Four months old male Wistar rats were randomly divided into fi ve experimental groups fed a standard diet, standard diet supplemented with 5% BLF, high-fat diet, high-fat diet with full-period (13 weeks) of 5% BLF supplementation and high-fat diet with partial-period (7 weeks) of 5% BLF supplementation. Gas-liquid chromatography was performed to analyze the fatty acids in hexane lipid extracts of whole rat brains.Supplementation with BLF did not induce signifi cant changes in fatty acid composition of whole brain phospholipids in rats fed the standard diet. In rats on high-fat diet concomitant (full-period) BLF supplementation increased eicosapentaenoic acid (20:5n-3, EPA), total n-6 and n-6/n-3 ratio, and decreased the percentage of oleic acid (18:1n-9) and estimated activity of Δ-9 desaturase. When BLF application was postponed (partial-period) in the case of developed hyperlipidemia, a decrease of stearic acid (18:0) accompanied with an increased estimated Δ-9 desaturase activity was observed. Regardless of BLF supplementation all high-fat diet-fed groups showed an elevated percentage of linoleic acid (18:2n-6, LA) and a reduced estimated Δ-6 desaturase activity.BLF contributes to the maintenance of stable fatty acid composition of brain phospholipids and supports normal brain function in high-fat diet rats, with more positive effects when BLF was applied before hyperlipidemia developed. This could be the mode of buckwheat health benefi cial effects on the brain.

show abstract

Docosahexaenoic acid synthesis from α-linolenic acid by rat brain is unaffected by dietary n-3 PUFA deprivation

Cited by 138 publications

References 55 publications

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

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

Linoleic and α-linolenic acid as precursor and inhibitor for the synthesis of long-chain polyunsaturated fatty acids in liver and brain of growing pigs

Effects Of Dietary Supplementation With A Mixture Of Buckwheat Leaf And Flower On Fatty Acid Composition Of Rat Brain Phospholipids

Contact Info

Product

Resources

About