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1.
Coralie Schnebelen Stéphane Grégoire Bruno Pasquis Corinne Joffre Catherine P. Creuzot-Garcher Alain M. Bron Lionel Bretillon Niyazi Acar 《Lipids》2009,44(5):465-470
The purpose of this study was to determine whether dietary n-3 and n-6 PUFA may affect retinal PUFA composition and PGE1 and PGE2 production. Male Wistar rats were fed for 3 months with diets containing: (1) 10% eicosapentaenoic acid (EPA) and 7% docosahexaenoic
acid (DHA), or (2) 10% γ-linolenic acid (GLA), or (3) 10% EPA, 7% DHA and 10% GLA, or (4) a balanced diet deprived of EPA,
DHA, and GLA. The fatty acid composition of retinal phospholipids was determined by gas chromatography. Prostaglandin production
was measured by enzyme immunoassay. When compared to rats fed the control diet, the retinal levels of DHA were increased in
rats fed both diets enriched with n-3 PUFA (EPA + DHA and EPA + DHA + GLA diets) and decreased in those supplemented with
n-6 PUFA only (GLA diet). The diet enriched with both n-6 and n-3 PUFA resulted in the greatest increase in retinal DHA. The
levels of PGE1 and PGE2 were significantly increased in retinal homogenates of rats fed with the GLA-rich diet when compared with those of animals
fed the control diet. These higher PGE1 and PGE2 levels were not observed in animals fed with EPA + DHA + GLA. In summary, GLA added to EPA + DHA resulted in the highest
retinal DHA content but without increasing retinal PGE2 as seen in animals supplemented with GLA only. 相似文献
2.
There is a significant interest in the interrelationship between long-chain n-3, and n-6 fatty acids due to their ability
to modulate eicosanoid production. In general, the intake of arachidonic acid (AA) results in enhanced eicosanoid production,
whereas n-3 polyunsaturated fatty acids (PUFA) decrease the production of eicosanoids from AA. The purpose of this study was
to investigate whether the effects of dietary AA on eicosanoid production in the rat were correlated with the AA and EPA levels
in platelets and aorta (eicosanoid-producing tissues). Four groups of male Sprague-Dawley rats were fed a highfat diet enriched
with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (approximately 100 mg/day of EPA+DHA) for 24 d. During the
last 10 d, the four groups were orally supplemented with 0,30,60, and 90 mg/day of ethyl arachidonate. A further group of
rats was fed a control diet (without longchain n-3 PUFA) for 24 d.In vitro aorta prostacyclin (PGI2) production, serum thromboxane A2 (TxA2) production and plasma, and platelet and aorta phospholipid (PL) fatty acids were measured. Enriching the diet with n-3 PUFA
resulted in significant reductions in tissue AA levels and an increase in the n-3 PUFA, particularly EPA. On this diet, the
AA to EPA ratio was 1:1 in platelet PL, and it was 2:1 in the aorta PL. There were significant decreases in thein vitro PGI2 and TxA2 production compared with the control animals. The inclusion of AA in the diet resulted in marked increases in AA levels in
the platelet and aorta PL with corresponding decreases in EPA. The lowest dose of AA (30 mg/rat) reversed the effects of 100
mg/day of n-3 PUFA on AA levels in platelet and aortic PL and onin vitro aorta PGI2 and serum TxA2 production. The dietary AA caused a differential (twofold) increase in TxA2 relative to PGI2 for all three levels of AA supplementation. There were greater changes in the levels of AA and/or EPA in platelet PL compared
with the aorta PL, which might have accounted for the differential effects of these PUFA on thromboxane production compared
with PGI2 production in this study. 相似文献
3.
To better understand the mode of action of ω3 fatty acids in cell membranes, human foreskin fibroblasts were grown in serum-free
medium supplemented with 50 μM oleic acid linoleic acid, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), and the
effects on membrane composition, fluorescence polarization and enzyme activities were followed. The cells were enriched with
EPA and DHA up to 7 and 13% of total lipids, respectively, of which >95% was associated with phospholipids. In addition, the
concentration of 22∶5n−3 increased with both EPA and DHA to 7.5, and 2.1% of the total fatty acids, respectively. When compared
to controls (oleic acid), cells treated with DHA showed a decrease in cholesterol, phospholipids, arachidonic acid (AA) and
free cholesterol/phospholipid ratio (P<0.05). In the presence of EPA, only decreases in AA and cholesterol were significant (P<0.05). Membrane fluidity, assessed by fluorescence anisotropy, was increased 16% in cells enriched with DHA (P<0.05), but showed no change with EPA or linoleic acid. There was an increase in membrane-associated 5′-nucleotidase (+27%)
and adenylate cyclase (+19%) activities (P<0.05), in DHA-enriched, but not in EPA-enriched cells, when compared with oleate controls. The studies show that incorporation
of DHA, but not EPA, into cell membranes of fibroblasts alters membrane biophysical characteristics and function. We suggest
that these two major n−3 fatty acids of fish oils have differential effects on cell membranes, and this may be related to
the known differences in their physiological effects. 相似文献
4.
A. Robles Medina A. Giménez Giménez F. García Camacho J. A. Sánchez Pérez E. Molina Grima A. Contreras Gómez 《Journal of the American Oil Chemists' Society》1995,72(5):575-583
n-3 Polyunsaturated fatty acids (n-3 PUFA) from the marine microalgaIsochrysis galbana were concentrated and purified by a two-step process—formation of urea inclusion compounds followed by preparative high-performance
liquid chromatography. These methods had been developed previously with fatty acids from cod liver oil. By the urea inclusion
compounds method, a mixture that contained 94% (w/w) stearidonic (SA), eicosapentaenoic (EPA), plus docosahexaenoic (DHA)
acids (4:1 urea/fatty acid ratio and 4°C crystallization final temperature) was obtained from cod liver oil fatty acids. Further
purification of SA, EPA, and DHA was achieved with reverse-phase C18 columns. These isolations were scaled up to a semi-preparative column. A PUFA concentrate was isolated fromI. galbana with methanol/water (80:20, w/w) or ethanol/water (70:30, w/w). With methanol/water, a 96% EPA fraction with 100% yield was
obtained, as well as a 94% pure DHA fraction with a 94% yield. With ethanol/water as the mobile phase, EPA and DHA fractions
obtained were 92% pure with yields of 84 and 88%, respectively. 相似文献
5.
The present study was designed to determine if dietary supply of long-chain fatty acid (LCFA, C20∶4n-6, and/or C22∶6n-3),
reflecting levels that might be incorporated into infant formulas, influences the fatty acid composition of the visual cell
membrane. The rod outer segment (ROS) of the retina was analyzed from rats fed diets varying in the ratio of 18∶2n-6 to 18∶3n-3
with or without 20∶4n-6 [arachidonic acid (AA)] and 22∶6n-3 (docosahexaenoic acid) from birth to six weeks of age. The level
of very long chain fatty acids (VLCFA, C24−C36) was identified using gas chromatography and gas chromatography-mass spectrometry. In the ROS, the highest relative percent
of AA was attained in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) of animals fed 1% AA diet, whereas feeding
0.7% docosahexaenoic acid (DHA) diet significantly increased the DHA level in PC, phosphatidylserine, and phosphatidylinositol
compared to feeding diets containing AA. VLCFA of n-6 and n-3 up to C36 were found in PC, with the most abundant fatty acids being C32 and C34. In PC, phosphatidylserine and PE, the n-6 tetraenoic VLCFA level was highly increased in animals fed 1% AA compared to other
dietary groups. This study suggests that dietary fat containing small amounts of AA or DHA is an important factor influencing
membrane fatty acid composition of the visual cell during development.
Based on a presentation at the AOCS Annual Meeting & Expo in San Antonio, Texas, May 7–11, 1995. 相似文献
6.
Lipids of selected molds grown for production of n−3 and n−6 polyunsaturated fatty acids 总被引:7,自引:0,他引:7
The lipid classes and component fatty acids of seven fungi were examined. Three marine fungi,Thraustochytrium aureum, Thraustochytrium roseum andSchizochytrium aggregatum (grown at 30, 25 and 25°C, respectively), produced less than 10% lipid but contained docosahexaenoic acid (DHA) up to 30%
and eicosapentaenoic acid (EPA) up to 11% of the total fatty acids.Mortierella alpinapeyron produced 38% oil containing solely n-6 polyunsaturated fatty acids (PUFA) with arachidonic acid (AA) at 11% of the total
fatty acids.Conidiobolus nanodes andEntomorphthora exitalis produced 25% oil and contained both n−3 and n−6 PUFA, with AA at 16% and 18%, respectively.Saprolegnia parasitica produced 10% oil and contained AA and EPA, respectively, at 19% and 18%. The triacylglycerol fraction always represented
the major component at between 44% and 68% of the total lipid. Each fungus, exceptT. aureum, had the greatest degree of fatty acid unsaturation in the phospholipid fraction. The triacylglycerol fraction ofT. aureum was the most unsaturated with DHA representing 29% (w/w) of all fatty acids present. The presence of the enzyme ATP:citrate
lyase correlated with the ability of molds to accumulate more than 10% (w/w) lipid when the fungi were grown in nitrogen-limiting
media. In those molds that failed to accumulate more than 10% lipid, the enzyme was absent. 相似文献
7.
Modulation of arachidonate and docosahexaenoate in Morone chrysops larval tissues and the effect on growth and survival 总被引:1,自引:0,他引:1
The extent to which extreme dietary levels of arachidonate (AA) and/pr docosahexaenoate (DHA) modulate lipid composition in
the body tissues and consequently affect growth and survival in freshwater Morone larvae species was examined. White bass, M. chrysops, larvae (day 24–46) were fed Artemia nauplii enriched with algal oils containing varying proportions of AA and DHA (from 0 to over 20% the total fatty acids).
Growth was significantly reduced (P<0.05) in larvae fed a DHA-deficient Artemia diet. Increases in dietary levels of AA also were associated with a significant growth reduction. However, the inhibitory
effect of AA on larvae growth could be suppressed by the dietary addition of DHA (at a level of 21.6% of the total fatty acids
in enrichment lipids). Larval brain+eyes tissue accumulated over 10 times more DHA than AA in its structural lipids (phosphatidylcholine,
phosphatidylethanolamine) at any dietary ratio. In contrast, DHA accumulation, as compared to AA, in gill lipids declined
considerably at higher than 10∶1 DHA/AA tissue ratios. DHA and eicosapentaenoic acid (EPA) contents in brain+eyes tissue were
most sensitive to competition from dietary AA, being displaced from the tissue at rates of 0.36±0.07 mg DHA and 0.46±0.11
mg EPA per mg increase in tissue AA, and 0.55±0.14 mg AA per mg increase in tissue DHA. On the other hand, AA and EPA levels
in gill tissue were most sensitive to dietary changes in DHA levels; AA was displaced at rates of 0.37±0.11 mg, whereas EPA
increased at rates of 0.68±0.28 mg per mg increase in tissue DHA. Results suggest that balanced dietary DHA/AA ratios (that
allow DHA/AA ratios of 2.5∶1 in brain+eyes tissue) promote a high larval growth rate, which also correlates with maximal regulatory
response in tissue essential fatty acids. 相似文献
8.
Helvi M. Vidgren Jyrki J. Ågren Ursula Schwab Tiina Rissanen Osmo Hänninen Matti I. J. Uusitupa 《Lipids》1997,32(7):697-705
The effects of n-3 fatty acid supplementation in the form of fresh fish, fish oil, and docosahexaenoic acid (DHA) oil on the
fatty acid composition of plasma lipid fractions, and platelets and erythrocyte membranes of young healthy male students were
examined. Altogether 59 subjects (aged 19–32 yr, body mass index 16.8–31.3 kg/m2) were randomized into the following diet groups: (i) control group; (ii) fish diet group eating fish meals five times per
week [0.38±0.04 g eicosapentaenoic acid (EPA) and 0.67±0.09 g DHA per day]; (iii) DHA oil group taking algae-derived DHA oil
capsules (1.68 g/d DHA oil group taking algae-derived DHA oil capsules (1.68 g/d DHA in triglyceride form); and (iv) fish
oil group (1.33 g EPA and 0.95 g DHA/d as free fatty acids) for 14 wk. The fatty acid composition of plasma lipids, platelets,
and erythrocyte membranes was analyzed by gas chromatography. The subjects kept 4-d food records four times during the study
to estimate the intake of nutrients. In the fish diet, in DHA oil, and in fish oil groups, the amounts of n-3 fatty acids
increased and those of n-6 fatty acids decreased significantly in plasma lipid fractions and in platelets and erythrocyte
membranes. A positive relationship was shown between the total n-3 polyunsaturated fatty acids (PUFA) and EPA and DHA intake
and the increase in total n-3 PUFA and EPA and DHA in all lipid fractions analyzed. DHA was preferentially incorporated into
phospholipid (PL) and triglyceride (TG) and there was very little uptake in cholesterol ester (CE), while EPA was preferentially
incorporated into PL and CE. The proportion of EPA in plasma lipids and platelets and erythrocyte membranes increased also
by DHA supplementation, and the proportion of linoleic acid increased in platelets and erythrocyte membranes in the DHA oil
group as well. These results suggest retroconversion of DHA to EPA and that DHA also interferes with linoleic acid metabolism. 相似文献
9.
Previous studies in our laboratory have shown that marine oils, with high levels of eicosapentaenoic (EPA, 20∶5n−3) and docosahexaenoic
acids (DHA, 22∶6n−3), inhibit the growth of CT-26, a murine colon carcinoma cell line, when implanted into the colons of male
BALB/c mice. Anin vitro model was developed to study the incorporation of polyunsaturated fatty acids (PUFA) into CT-26 cells in culture. PUFA-induced
changes in the phospholipid fatty acid composition and the affinity with which different fatty acids enter the various phospholipid
species and subspecies were examined. We found that supplementation of cultured CT-26 cells with either 50 μM linoleic acid
(LIN, 18∶2n−6), arachidonic acid (AA, 20∶4n−6), EPA, or DHA significantly alters the fatty acid composition of CT-26 cells.
Incorporation of these fatty acids resulted in decreased levels of monounsaturated fatty acids, while EPA and DHA also resulted
in lower levels of AA. While significant elongation of both AA and EPA occurred, LIN remained relatively unmodified. Incorporation
of radiolabeled fatty acids into different phospholipid species varied significantly. LIN was incorporated predominantly into
phosphatidylcholine and had a much lower affinity for the ethanolamine phospholipids. DHA had a higher affinity for plasmenylethanolamine
(1-O-alk-1′-enyl-2-acyl-sn-glycero-3-phosphoethanolamine) than the other fatty acids, while EPA had the highest affinity for phosphatidylethanol-amine
(1,2-diacyl-sn-glycero-3-phosphoethanolamine). These results demonstrate that,in vitro, significant differences are seen between the various PUFA in CT-26 cells with respect to metabolism and distribution, and
these may help to explain differences observed with respect to their effects on tumor growth and metastasis in the transplantable
model. 相似文献
10.
The effect of unsaturated fatty acids on the abundance of Δ6 desaturase (D6D) mRNA and the fatty acid composition of HepG2
cell membranes was examined. Supplementation of HepG2 cells with oleic acid (18:1n-9, OA), linoleic acid (18:2n-6, LA), α-linolenic
acid (18:3n-3, ALA), arachidonic acid (20:4n-6, AA) or eicosapentaenoic acid (20:5n-3, EPA) reduced D6D mRNA abundance by
39 ± 6.6, 40 ± 2.2, 31 ± 5.2, 55 ± 4.8, and 52 ± 5.0%, respectively, compared with control cells. Despite the reduction in
D6D mRNA abundance, the level of D6D conversion products (20:3n-9, EPA and AA) in OA, ALA and LA supplemented cells, respectively,
was elevated above that in control cells. Our results suggest that although unsaturated fatty acids decrease the abundance
of D6D mRNA by as much as 50%, the conversion of polyunsaturated fatty acids and accumulation of long chain polyunsaturated
fatty acids (LCPUFA) in HepG2 cell phospholipids continues to occur. 相似文献
11.
Effects of an eicosapentaenoic and docosahexaenoic acid concentrate on a human lung carcinoma grown in nude mice 总被引:1,自引:0,他引:1
M. G. de Bravo R. J. de Antueno J. Toledo M. E. De Tomás O. F. Mercuri C. Quintans 《Lipids》1991,26(11):866-870
The effects of the n−3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on the growth of a human lung
mucoepidermoid carcinoma (HLMC) in athymic mice were studied. The mice were divided into three groups which were given either
a control chow diet (C), a chow diet supplemented with EPA/DHA (P) (25 or 50 mg of free n−3 fatty acids/g of pellet/day),
or chow diet supplemented with palmitic acid (S) (isocaloric with P). Two independent experimental schedules were followed:
i) host mice bearing either tumors that were allowed to reach 4000 mm3, or only 35 mm3, were fed C, P or S for 21 or 41 days; ii) animals were fed C, P and S for 9 days before tumor implant and were maintained
on these diets throughout tumor growth. Food consumption, mouse weight and liver/body weight ratio showed no significant differences
between supplemented diets and chow. Tumor growth was markedly inhibited (45%) in both experiments by the EPA/DHA supplemented
diet. In Experiment 2, only 60% of mice fed diet P had tumors. The fatty acid composition of neutral and polar lipids of host
liver and tumor reflected the dietary intake of n−3 fatty acids; the content of arachidonic acid was reduced by 50%, and EPA/DHA
was increased 3-to 5-fold. Tumor prostaglandin E2 levels were reduced 7.4-fold in the P group. The reduced PGE2 content may be a factor in tumor growth inhibition.
Preliminary data were presented at the Annual Meeting of the American Oil Chemists' Society, (1990), Baltimore, MD, (de Antueno,
R.J., Bravo, M.G. de, Toledo, J., De Tomas, M.E., Mercuri, O., Quintans, C. (1990)INFORM 1, 328 (Abstract HH1). 相似文献
12.
Leon C. Boyd Mei Fong King Brian Sheldon 《Journal of the American Oil Chemists' Society》1992,69(4):325-330
The stability of unsaturated fatty acids to oxidation was monitored by following gas chromatographic (GC) analyses of headspace
volatiles in comparison to changes in polyunsaturated fatty acids (PUFA) and increases in malonaldehydevia the 2-thiobarbituric (TBA) assay. Pure standards of linoleic acid (Lo) and n-3 fatty acids [eicosapentaenoic (EPA) and docosahexaenoic
acid (DHA)] were added to headspace vials, equilibrated in air for 10 min, followed by heating at 80°C in teflon-capped vials
for different time intervals. Headspace analysis showed increases in acetaldehyde, propenal, and propanal, corresponding to
the oxidation of n-3 fatty acids, whereas hexanal production corresponded to losses of linoleic acid. The analysis of propanal
by GC-headspace after only five minutes of heating appeared to be the most effective method of monitoring the oxidation of
n-3 fatty acids, as indicated by correlations between TBA values and loss of PUFA. The oxidation of Lo, EPA and DHA appeared
to be a function of the number of double bonds. Correlations between PUFA depletion, TBA values and volatile formation indicate
that under the prescribed conditions of this experiment, GC-headspace analysis of propanal and pentane/hexanal is an excellent
method for following the oxidation of selected n-3 fatty acids and linoleic acid. 相似文献
13.
It is well known that vascular smooth muscle cell (SMC) proliferation is a key step in atheromatous plaque formation. Thromboxane
A2 (T×A2), released from aggregating platelets and an injured vessel wall, may play an important role in the development of atheromatous
plaque. Many animal studies have suggested that n−3 polyunsaturated fatty acids eicosapentaenoic acid (EPA, 20∶5n−3) and docosahexaenoic
acid (DHA, 22∶6n−3) present in the fish oils have antiatherosclerotic effects. In the present study, we investigated the effect
of EPA and DHA on I×A2-induced SMC proliferation. To determine the functional selectivity of n−3 fatty acids, we also tested the effect of arachidonic
acid (AA, 20∶4n−6), γ-linolenic acid) (INA, 18∶3n−6), and oleic acid (OA, 18∶1n−9) on T×A2-induced SMC proliferation. Only LPA and DHA prevented the SMC proliferation induced by the T×A2 mimetic U46619. When EPA and DHA were added together in the ratio in which they are present in menhaden oil, EPA and DHA
acted synergistically to block the SMC proliferation induced by the TXA2-mimetic. These findings suggest that the n−3 polyunsaturated fatty acids in fish oils may exert antiatherosclerotic effects
by blocking the mitogenstimulated proliferation of SMC. 相似文献
14.
Telle-Hansen VH Larsen LN Høstmark AT Molin M Dahl L Almendingen K Ulven SM 《Lipids》2012,47(2):151-160
Intake of fish and omega-3 (n-3) fatty acids is associated with a reduced concentration of plasma triacylglycerols (TAG) but
the mechanisms are not fully clarified. Stearoyl-CoA desaturase-1 (SCD1) activity, governing TAG synthesis, is affected by
n-3 fatty acids. Peripheral blood mononuclear cells (PBMC) display expression of genes involved in lipid metabolism. The aim
of the present study was to estimate whether intake of lean and fatty fish would influence n-3 fatty acids composition in
plasma phospholipids (PL), serum TAG, 18:1n-9/18:0 ratio in plasma PL, as well as PBMC gene expression of SCD1 and fatty acid
synthase (FAS). Healthy males and females (n = 30), aged 20–40, consumed either 150 g of cod, salmon, or potato (control) daily for 15 days. During intervention docosahexaenoic
acid (DHA, 22:6n-3) increased in the cod group (P < 0.05), while TAG concentration decreased (P < 0.05). In the salmon group both eicosapentaenoic acid (EPA, 20:5n-3) and DHA increased (P < 0.05) whereas TAG concentration and the 18:1n-9/18:0 ratio decreased (P < 0.05). Reduction of the 18:1n-9/18:0 ratio was associated with a corresponding lowering of TAG (P < 0.05) and an increase in EPA and DHA (P < 0.05). The mRNA levels of SCD1 and FAS in PBMC were not significantly altered after intake of cod or salmon when compared
with the control group. In conclusion, both lean and fatty fish may lower TAG, possibly by reducing the 18:1n-9/18:0 ratio
related to allosteric inhibition of SCD1 activity, rather than by influencing the synthesis of enzyme protein. 相似文献
15.
Eicosapentaenoic acid is primarily responsible for hypotriglyceridemic effect of fish oil in humans 总被引:4,自引:0,他引:4
The aim of this study was to determine whether eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), or both, were responsible
for the triglyceride (TG)-lowering effects of fish oil. EPA (91% pure) and DHA (83% pure), a fish oil concentrate (FOC; 41%
EPA and 23% DHA) and an olive oil (OO) placebo (all ethyl esters) were tested. A total of 49 normolipidemic subjects participated.
Each subject was given placebo for 2–3 wk and one of the n-3 supplements for 3 wk in randomized, blinded trials. The target
n-3 fatty acid (FA) intake was 3 g/day in all studies. Blood samples were drawn twice at the end of each supplementation phase
and analyzed for lipids, lipoproteins, and phospholipid FA composition. In all groups, the phospholipid FA composition changed
to reflect the n-3 FA given. On DHA supplementation, EPA levels increased to a small but significant extent, suggesting that
some retroconversion may have occurred. EPA supplementation did not raise DHA levels, however, FOC and EPA produced significant
decreases in both TG and very low density lipoprotein (VLDL) cholesterol (C) levels (P<0.01) and increases in low density lipoprotein (LDL) cholesterol levels (P<0.05). DHA supplementation did not affect cholesterol, triglyceride, VLDL, LDL, or high density lipoprotein (HDL) levels,
but it did cause a significant increase in the HDL2/HDL3 cholesterol ratio. We conclude that EPA appears to be primarily responsible for TG-lowering (and LDL-C raising) effects of
fish oil. 相似文献
16.
The efficacy of individual ω-t-3 polyunsaturated fatty acids (PUFA) in altering eicosanoid synthesis in peritoneal macrophages
was studied by feeding mice for 10 days a diet containing 2 wt% fat, which included 0.5 wt% ethyl esters of eicosapentaenoic
acid (EPA), docosahexaenoic acid (DHA) or linolenic acid (LNA). Upon stimulation with calcium ionophore A23187, macrophages
from these animals produced significantly lower amounts of leukotriene C4, leukotriene B4 and 12-hydroxyeicosatetraenoic acid, prostaglandin E2 and 6-keto prostaglandin F1α compared with those obtained from animals on the diets containing olive oil or safflower oil. The decrease in leukotriene
synthesis was similar in the animals fed DHA, EPA or LNA diets. This depression of eicosanoids by DHA and EPA was associated
with decreased levels of arachidonic acid (AA); however, LA that altered eicosanoids did not have the same effect on AA levels. 相似文献
17.
The biological activity, including metabolism and modulation of ornithine decarboxylase activity and DNA synthesis, of arachidonic
acid (AA) and eicosapentaenoic acid (EPA) were compared in epidermal cells from SENCAR mice. Radiolabelled AA and EPA were
found to be similarly incorporated into and released from membrane phospholipids of unstimulated cultures. However, when cells
were stimulated with the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA), the release of AA was significantly higher
than the release of EPA. The extent of metabolism of AA and EPA to prostaglandins was determined in both freeze-thawed cell
preparations and in viable cultured cells. In the freeze-thawed preparations, use of AA as a substrate resulted in significantly
more PGF than when EPA was used as the substrate. However, more PGE3 was formed than PGE2. PGD levels were the same for either fatty acid precursor. Prostaglandin production was also determined in viable cultured
cells since other influences such as phospholipase A2 activity can modify prostaglandin production. Control cultures prelabelled with either AA or EPA produced similar amounts
of the respective PGF, PGE, and PGD. However, TPA-stimulated cultures produced significantly higher amounts of each prostaglandin
in cultures prelabelled with AA compared to cells prelabelled with EPA. HETE or HEPE production was the same both for cultured
cells prelabelled with AA or EPA and for homogenates from uncultured cells incubated directly with the radiolabelled fatty
acids. TPA-induced ornithine decarboxylase (ODC) was significantly higher in AA-treated cultures compared to EPA-treated cultures.
AA supports DNA synthesis to a greater extent than EPA, either alone or in the presence of TPA. These findings suggest that
AA and EPA do not have equivalent biological activity in mouse epidermal cells. 相似文献
18.
Arachidonic acid to eicosapentaenoic acid ratio in blood correlates positively with clinical symptoms of depression 总被引:13,自引:0,他引:13
In this study of 20 moderately to severely depressed patients, diagnosed using current research diagnostic criteria and excluding
known bipolar affective disorder and reactive depression, we investigated relationships between severity of depression and
levels and ratios of n-3 and n-6 long-chain polyunsaturated fatty acids (PUFA) in plasma and erythrocyte phospholipids (PL).
Severity of depression was measured using the 21-item Hamilton depression rating scale (HRS) and a second linear rating scale
(LRS) of severity of depressive symptoms that omitted anxiety symptoms. There was a significant correlation between the ratio
of erythrocyte PL arachidonic acid (AA) to eicosapentaenoic acid (EPA) and severity of depression as rated by the HRS (P<0.05) and the LRS for depression (P< 0.01). There was also a significant negative correlation between erythrocyte EPA and the LRS (P<0.05). The AA/EPA ratio in plasma PL and the ratio of erythrocyte long-chain (C20 and C22 carbon) n-6 to long-chain n-3 PUFA were also significantly correlated with the LRS (P<0.05). These findings do not appear to be simply explained by differences in dietary intake of EPA. We cannot determine whether
the high ratios of AA/EPA in both plasma and erythrocyte PL are the result of depression or whether tissue PUFA change predate
the depressive symptoms. We suggest, however, that our findings provide a basis for studying the effect of the nutritional
supplementation of depressed subjects, aimed at reducing the AA/EPA ratio in tissues and severity of depression. 相似文献
19.
Lipase-assisted concentration of n-3 polyunsaturated fatty acids in acylglycerols from marine oils 总被引:1,自引:0,他引:1
Udaya N. Wanasundara Fereidoon Shahidi 《Journal of the American Oil Chemists' Society》1998,75(8):945-951
Preparation of n-3 polyunsaturated fatty acid (PUFA) concentrates from seal blubber oil (SBO) and menhaden oil (MHO) in the
form of acylglycerols was carried out by hydrolysis with a number of commercial microbial lipases. The lipases tested were
Aspergillus niger, Candida cylindracea (CC), Chromobacterium viscosum, Geotrichum candidum, Mucor miehei, Pseudomonas sp., Rhizopus oryzae, and Rhizopus niveus. After lipase-assisted hydrolysis of oils, free fatty acids were removed, and fatty acid composition of the mixture containing
mono-, di-, and triacylglycerols was determined. All lipases were effective in increasing the n-3 PUFA content of the remaining
acylglycerols of both SBO and MHO. The highest concentration of n-3 PUFA was provided by CC lipase; 43.5% in SBO [9.75% eicosapentaenoic
acid (EPA), 8.61% docosapentaenoic acid (DPA), and 24.0% docosahexaenoic acid (DHA)] and 44.1% in MHO (18.5% EPA, 3.62% DPA,
and 17.3% DHA) after 40 h of hydrolysis. Thus, CC lipase appears to be most suitable for preparation of n-3 PUFA in the acylglycerol
form from marine oils. 相似文献
20.
Regulation by long-chain fatty acids of the expression of cholesteryl ester transfer protein in HepG2 cells 总被引:2,自引:0,他引:2
Cholesteryl ester transfer protein (CETP) is an important determinant of lipoprotein function, especially high density lipoprotein
(HDL) metabolism, and contributes to the regulation of plasma HDL levels. Since saturated and polyunsaturated fatty acids
(FA) appear to influence the CETP activity differently, we decided to investigate the effects of FA on the expression of CETP
mRNA in HepG2 cells using an RNA blot hybridization analysis. Long-chain FA (>18 carbons) at a 0.5 mM concentration were added
to the medium and incubated with cells for 48 h at 37°C under 5% CO2. After treatment with 0.5 mM arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic acid (DHA), the levels of CETP
mRNA were less than 50% of the control levels (AA, P=0.0005; EPA, P<0.01; DHA, P<0.0001), with a corresponding significant decrease in the CETP mass. These results suggest that FA regulate the gene expression
of CETP in HepG2 and this effect is dependent upon the degree of unsaturation of the acyl carbon chain in FA. 相似文献