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1.
John-Bjarne Hansen Sameline Grimsgaard Hugo Nilsen Arne Nordøy Kaare H. Bønaa 《Lipids》1998,33(2):131-138
Fourteen healthy volunteers were randomly allocated to receive 4 g highly purified ethyl esters of eicosapentaenoic acid (EPA)
(95% pure, n=7) or docosahexaenoic acid (DHA) (90% pure, n=7) daily for 5 wk in supplement to their ordinary diet. The n−3 fatty acids were given with a standard high-fat meal at the
beginning and the end of the supplementation period. EPA and DHA induced a similar incorporation into chylomicrons which peaked
6 h after the meal. The relative uptake of EPA and DHA from the meal was >90% compared with the uptake of oleic acid. During
absorption, there was no significant elongation or retroconversion of EPA or DHA in total chylomicron fatty acids. The concentration
of EPA decreased by 13% and DHA by 62% (P<0.001) between 6 and 8 h after the meal. During the 5-wk supplementation period, EPA showed a more rapid and comprehensive
increase in serum phospholipids than did DHA. DHA was retroconverted to EPA, whereas EPA was elongated to docosapentaenoic
acid (DPA). The postprandial triglyceridemia was suppressed by 19 and 49% after prolonged intake of EPA and DHA, respectively,
indicating that prolonged intake of DHA is equivalent to or even more efficient than that of EPA in lowering postprandial
triglyceridemia. This study indicates that there are metabolic differences between EPA and DHA which may have implications
for the use of n−3 fatty acids in preventive and clinical medicine. 相似文献
2.
Indian diets comprising staples such as cereals, millets, and pulses provide 4.8 energy % from linoleic acid (18∶2n−6) but
fail to deliver adequate amounts of n−3 FA. Consumption of long-chain n−3 PUFA such as EPA (20∶5n−3) and DHA (22∶6n−3) is
restricted to those who consume fish. The majority of the Indian population, however, are vegetarians needing additional dietary
sources of n−3 PUFA. The present work was designed to use n−3 FA-enriched spray-dired milk powder to provide n−3 FA. Whole
milk was supplemented with linseed oil to provide α-linolenic acid (LNA, 18∶3n−3), with fish oil to provide EPA and DHA, or
with groundnut oil (GNO), which is devoid of n−3 PUFA, and then spray-dired. Male Wistar rats were fed the spray-dired milk
formulations for 60 d. The rats given formulations containing n−3 FA showed significant increases (P<0.001) in the levels of LNA or EPA/DHA in the serum and in tissue as compared with those fed the GNO control formulation.
Rats fed formulations containing n−3 FA had 30–35% lower levels of serum total cholesterol and 25–30% lower levels of serum
TAG than control animals. Total cholesterol and TAG in the livers of rats fed the formulations containing n−3 FA were lower
by 18–30% and 11–18%, respectively, compared with control animals. This study showed that spray-dried milk formulations supplemented
with n−3 FA are an effective means of improving dietary n−3 FA intake, which may decrease the risk factors associated with
cardiovascular disease. 相似文献
3.
The effects of supplementation with docosahexaenoic acid (DHA) on DHA levels in serum, seminal plasma, and sperm of asthenozoospermic
men as well as on sperm motility were examined in a randomized, double-blind, placebo-controlled manner. Asthenozoospermic
men (n=28; ≤50% motility) were supplemented with 0, 400, or 800 mg DHA/d for 3 mon. Sperm motility and the fatty acid composition
of serum, seminal plasma, and sperm phospholipid were determined before and after supplementation. In serum, DHA supplementation
resulted in decreases in 22∶4n−6 (−30% in the 800-mg DHA group only) and total n−6 (−6 and −12% in the 400- and 800-mg DHA
groups, respectively) fatty acids. Increases were noted in DHA (71 and 131% in the 400- and 800-mg DHA groups, respectively),
total n−3 fatty acids (42 and 67% in the 400- and 800-mg DHA groups, respectively), and the n−3/n−6 ratio (50 and 93% in the
400- and 800-mg DHA groups, respectively). In seminal plasma, DHA supplementation resulted in a decrease in 22∶4n−6 (−31%
in the 800-mg DHA group only) and an increase in the ratio of n−3 to n−6 (35 and 33% in the 400- and 800-mg DHA groups, respectively).
There were insignificant increases in DHA and total n−3 fatty acids. In sperm, decreases were noted in 22∶4n−6 (−37 and −31%
in the 400-and 800-mg DHA groups, respectively). There were no other changes. There was no effect of DHA supplementation on
sperm motility. The results show that dietary DHA supplementation results in increased serum- and possibly seminal plasma—phospholipid
DHA levels, without affecting the incorporation of DHA into the spermatozoa phospholipid in asthenozoospermic men. This inability
of DHA to be incorporated into sperm phospholipid is most likely responsible for the observed lack of effect of DHA supplementation
on sperm motility. 相似文献
4.
We have reported that dietary fish oil (FO) leads to the incorporation of long-chain n−3 PUFA into the gut tissue of small
animal models, affecting contractility, particularly of rat ileum. This study examined the FO dose response for the incorporation
of n−3 PUFA into ileal tissue and how this correlated with in vitro contractility. Groups of ten to twelve 13-wk-old Wistar-Kyoto rats were fed 0, 1, 2.5, and 5% FO-supplemented diets balanced
with sunflower seed oil for 4 wk, after which ileal total phospholipid FA were determined and in vitro contractility assessed. For the total phospholipid fraction, increasing the dietary FO levels led to a significant increase
first evident at 1% FO, with a stepwise, nonsaturating six-fold increase in n−3 PUFA as EPA (20∶5n−3), DPA (docosapentaenoic
acid, 22∶5n−3), and DHA, but mainly as DHA (22∶6n−3), replacing the n−6 PUFA linoleic acid (18∶2n−6) and arachidonic acid
(20∶4n−6) over the dosage range. There was no difference in KCl-induced depolarization-driven contractility. However, a significant
increase in receptor-dependent maximal contractility occurred at 1% FO for carbachol and at 2.5% FO for prostaglandin E2, with a concomitant increase in sensitivity for prostaglandin E2 at 2.5 and 5% FO. These results demonstrate that significant increases in ileal membrane n−3 PUFA occurred at relatively
low doses of dietary FO, with differential receptor-dependent increases in contractility observed for muscarinic and prostanoid
agonists. 相似文献
5.
Fatty acid composition of habitual omnivore and vegetarian diets 总被引:1,自引:0,他引:1
High-fat diets are implicated in the onset of cardiovascular disease (CVD), cancer, and obesity. Large intakes of saturated
and trans FA, together with low levels of PUFA, particularly long-chain (LC) omega-3 (n−3) PUFA, appear to have the greatest impact
on the development of CVD. A high n−6∶n−3 PUFA ratio is also considered a marker of elevated risk of CVD, though little accurate
data on dietary intake is available. A new Australian food composition database that reports FA in foods to two decimal places
was used to assess intakes of FA in four habitual dietary groups. Analysis using the database found correlations between the
dietary intakes of LC n−3 PUFA and the plasma phospholipid LC n−3 PUFA concentrations of omnivore and vegetarian subjects.
High meat-eaters (HME), who consumed large amounts of food generally, had significantly higher LC n−3 PUFA intakes (0.29 g/d)
than moderate meat-eaters (MME) (0.14 g/d), whose intakes in turn were significantly higher than those of ovolacto-vegetarians
or vegans (both 0.01 g/d). The saturated FA intake of MME subjects (typical of adult male Australians) was not different from
ovolacto-vegetarian intakes, whereas n−6∶n−3 intake ratios in vegetarians were significantly higher than in omnivores. Thus,
accurate dietary and plasma FA analyses suggest that regular moderate consumption of meat and fish maintains a plasma FA profile
possibly more conducive to good health. 相似文献
6.
Chapkin RS Hong MY Fan YY Davidson LA Sanders LM Henderson CE Barhoumi R Burghardt RC Turner ND Lupton JR 《Lipids》2002,37(2):193-199
There is experimental evidence that dietary fish oil, which contains the n−3 fatty acid family, i.e., EPA and DHA, protects
against colon tumor development, in part by increasing apoptosis. Since mitochondria can act as central executioners of apoptosis,
we hypothesized that EPA and DHA incorporation into colonocyte mitochondrial membranes, owing to their high degree of unsaturation,
would enhance susceptibility to damage by reactive oxygen species (ROS) generated via oxidative phosphorylation. This, in turn, would compromise mitochondrial function, thereby initiating apoptosis. To test
this hypothesis, colonic crypts were isolated from rats fed either fish oil, purified n−3 fatty acid ethyl esters, or corn
oil (control). Dietary lipid source had no effect on colonic mitochondrial phospholipid class mole percentages, although incorporation
of EPA and DHA was associated with a reduction in n−6 fatty acids known to enhance colon tumor development, i.e., linoleic
acid (LNA) and its metabolic product, arachidonic acid (ARA). Select compositional changes in major phospholipid pools were
correlated to alterations in mitochondrial function as assessed by confocal microscopy. The mol% sum of LNA plus ARA in cardiolipin
was inversely correlated with ROS (P=0.024). Ethanolamine glycerophospholipid ARA (P=0.046) and choline glycerophospholipid INA (P=0.033) levels were positively correlated to mitochondrial membrane potential. In contrast, ethanolamine glycerophospholipid
EPA (P=0.042) and DHA (P=0.024), levels were negatively correlated to mitochondrial membrane potential. Additionally, EPA and DHA levels in choline
glycerophospholipids (P=0.026) were positively correlated with caspase 3 activity. These data provide evidence in vivo indicating that dietary FPA and DHA induce compositional changes in colonic mitochondrial membrane phospholipids that facilitate
appotosis. 相似文献
7.
Five groups of salmon, of initial mean weight 127±3 g, were fed increasing levels of dietary linseed oil (LO) in a regression
design. The control diet contained capelin oil (FO) only, and the same oil was blended with LO to provide the experimental
diets. After an initial period of 40 wk, all groups were switched to a finishing diet containing only FO for a further 24
wk. Growth and flesh lipid contents were not affected by dietary treatment. The FA compositions of flesh total lipids were
linearly correlated with dietary FA compositions (r
2=0.88–1.00, P<0.0001). LO included at 50% of added dietary lipids reduced flesh DHA and EPA (20∶5n−3) concentrations to 65 and 58%, respectively,
of the concentrations in fish fed FO. Feeding 100% LO reduced flesh DHA and EPA concentrations to 38 and 30%, respectively,
of the values in fish fed FO. Differences between diet and flesh FA concentrations showed that 16∶0, 18∶1n−9, and especially
DHA were preferentially retained in flesh, whereas 18∶2n−6, 18∶3n−3, and 22∶1n−11 were selected against and presumably utilized
for energy. In fish previously fed 50 and 100% LO, feeding a finishing diet containing FO for 16 wk restored flesh DHA and
EPA concentrations, to ≈80% of the values in fish fed FO throughout. Flesh DHA and EPA concentrations in fish fed up to 50%
LO were above recommended intake values for humans for these EFA. This study suggests that LO can be used as a substitute
for FO in seawater salmon feeds and that any reductions in DHA and EPA can be largely overcome with a finishing diethigh in
FO before harvest. 相似文献
8.
Cleland LG Proudman SM Hall C Stamp LK McWilliams L Wylie N Neumann M Gibson RA James MJ 《Lipids》2003,38(4):419-424
Dietary fish oil supplements have been shown to have benefits in rheumatoid arthritis (RA), other inflammatory diseases, and
in cardiovascular disease. As with any medical advice, variability will exist with regard to adherence and consequent biochemical
or pharmacophysiologic effects. The aim was to explore the utility of plasma phospholipid EPA as a measure of n−3 PUFA intake
and response to standardized therapeutic advice given in an outpatient or office practice setting, to increase dietary n−3
PUFA, including a fish oil supplement. Patients with early RA were given verbal and written advice to alter their dietary
n−3 PUFA intake, including ingestion of 20 mL of bottled fish oil on juice daily. The advice included instructions to increase
n−3 PUFA and to avoid foods rich in n−6 PUFA. Every 3 mon, blood samples were obtained for analysis of plasma phospholipid
FA. Plasma phospholipid EPA was used as the primary index of n−3 PUFA intake. A diverse response was seen, with about one-third
of patients achieving a substantial elevation of plasma phospholipid EPA over the 12-mon study period. A third had little
change, with the remainder achieving intermediate levels. Data obtained longitudinally from individual patients indicated
that substantial elevations of EPA (>5% total plasma phospholipid FA) could be maintained for more than 3 yr. Plasma phospholipid
EPA is a convenient measure of adherence to advice to take a dietary n−3 PUFA-rich fish oil supplement. This measure may prove
a useful adjunct to intention to treat analyses in determining the effect of dietary fish oil supplements on long-term outcomes
in arthritis and other chronic inflammatory diseases. It may also provide a guide to the effectiveness of therapeutic and
preventive messages designed to increase n−3 PUFA intake. 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 influence of dietary fish oil containing n−3 polyunsaturated fatty acids on the biosynthesis of triacylglycerol relative
to total individual phospholipids was studied in rat liverin vivo. The dietary lipid (10% by weight of diet) was either sunflower oil enriched in linoleic acid (SO group) or MaxEPA fish oil/sunflower
oil, 9∶1 by weight (FO group) enriched in eicosapentaenoic acid (EPA, 20∶5n−3) plus docosahexaenoic acid (DHA, 22∶6n−3). After
a 3-week feeding period, the triacylglycerol content (in μmmol/g liver) was 44% lower in the FO group relative to the SO animals.
Thein vivo incorporation of [3H]glycerol into individual hepatic lipids resulted in triacyl-glycerol/total phospholipid radioactivity ratios of 2.1 and
0.9 for the SO and FO groups, respectively. These results indicate an inhibitory effect of dietary EPA/DHA on triacylglycerol
relative to phospholipid synthesis from intermediary 1,2-diacylglycerol in rat liverin vivo. This metabolic alteration was accompanied by a substantially lower amount (in μmol/g liver) of arachidonic acid and higher
levels of EPA plus DHA in the triacylglycerol, choline glycerophospholipid (CGP), and ethanolamine glycerophospholipid (EGP)
of the FO group. A moderately higher labelling of the EGP from [3H]glycerol was observed in the FO as compared to the SO group (as evidenced by CGP/EGP radioactivity ratios of 1.3∶1 and 1.8∶1,
respectively). The present study providesin vivo evidence for a dampening effect of dietary fish oil on the synthesis of liver triacylglycerol relative to phospholipid and
a moderate alteration ofde novo synthesis of individual phospholipids.
Presented in part at the 80th Annual Meeting of the AOCS in Cincinnati, Ohio (May, 1989). 相似文献
11.
Docosahexaenoic acid (DHA, 22∶6n−3) is an n−3 polyunsaturated fatty acid which attenuates the development of hypertension
in spontaneously hypertensive rats (SHR). The effects of DHA on delta-9-desaturase activity in hepatic microsomes and fatty
acid composition were examined in young SHR. Two groups of SHR were fed either a DHA-enriched diet or a control diet for 6
wk. Desaturase activity and fatty acid composition were determined in hepatic microsomes following the dietary treatments.
Delta-9-desaturase activity was decreased by 53% in DHA-fed SHR and was accompanied by an increase in 16∶0 and a reduction
in 16∶1n−7 content in hepatic microsomes. The DHA diet also increased the levels of eicosapentaenoic acid (20∶5n−3) and DHA.
The n−6 fatty acid content was also affected in DHA-fed SHR as reflected by a decrease in gamma-linolenic acid (18∶3n−6),
arachidonic acid (20∶5n−6), adrenic acid (22∶4n−6), and docosapentaenoic acid (22∶5n−6). A higher proportion of dihomo-gamma-linolenic
acid (20∶3n−6) and a lower proportion of 20∶4n−6 is indicative of impaired delta-5-desaturase activity. The alterations in
fatty acid composition and metabolism may contribute to the antihypertensive effect of DHA previously reported. 相似文献
12.
Fatty acid analysis of blood serum, seminal plasma, and spermatozoa of normozoospermic vs. Asthernozoospermic males 总被引:2,自引:0,他引:2
Docosahexaenoic acid (DHA; 22∶6n−3) is found in extremely high levels in human ejaculate with the majority occurring in the
spermatozoa. However, the relative concentration of DHA and other fatty acids, in blood serum, seminal plasma, and spermatozoa
of asthenozoospermic vs. normozoospermic individuals is not known. We analyzed the phospholipid fatty acid composition of
blood serum, seminal plasma, and spermatozoa of normozoospermic men and asthenozoospermic men in order to determine if DHA
levels, as well as the levels of other fatty acids, differed. The serum phospholipid DHA levels were similar in the two groups,
suggesting similar intakes of dietary DHA. On the other hand, seminal plasma levels of DHA (3.0 vs. 3.7%) and total polyunsaturated
fatty acids (PUFA) (11.8 vs. 13.5%) were significantly lower in asthenozoospermic vs. normozoospermic men, respectively, while
18∶1 (19.0 vs. 16.8%) and monounsaturated fatty acids (MUFA) (24.2 vs. 21.7%) were significantly higher in the asthenozoospermic
vs. the normozoospermic men. Spermatozoa from asthenozoospermic men had higher levels of 18∶1, 20∶0, 22∶0, 22∶1, and 24∶0
than sperm from normozoospermic men, and lower levels of 18∶0 and DHA (8.2 vs. 13.8%). Furthermore, total MUFA (19.3 vs. 16.5%)
was higher and total PUFA (19.0 vs. 24.0%), n−3 fatty acids (9.3 vs. 14.6%), and the ratio of n−3 to n−6 fatty acids (1.0
vs. 1.6) were lower in the asthenozoospermic men. Therefore, in asthenozoospermic individuals, lower levels of DHA in the
seminal plasma, but not in the blood serum, mimic the decreased concentrations of DHA in the spermatozoa. This suggests that
the lower concentrations of spermatozoon DHA in these individuals are due not to dietary differences but to some type of metabolic
difference in the asthenozoopermic men. 相似文献
13.
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
14.
Blood phospholipid fatty acid analysis of adults with and without attention deficit/hyperactivity disorder 总被引:5,自引:0,他引:5
Several psychiatric disorders, including juvenile Attention Deficit/Hyperactivity Disorder (ADHD), have been associated with
abnormalities of certain long-chain PUFA (LCPUFA). Despite this reported association, the FA levels of patients with the adult
form of ADHD have not previously been evaluated. In this study we measured the total blood phospholipid FA concentrations
in 35 control subjects and 37 adults with ADHD symptoms to determine whether adults with ADHD symptoms would show abnormalities
of FA relative to control subjects. In the serum phospholipids, adults with ADHD symptoms had significantly lower levels of
total saturated, total polyunsaturated, and total omega-6 (n−6) FA, as well as the omega-3 (n−3) LCPUFA DHA (22∶6n−3), and
significantly higher levels of total monounsaturated FA and the n−3 LCPUFA docosapentaenoic acid (22∶5n−3). In the erythrocyte
membrane phospholipids, adults with ADHD symptoms had significantly lower levels of total PUFA, total n−3 FA, and DHA, and
significantly higher levels of total saturated FA. Neither serum nor erythrocyte membrane phospholipid DHA was related to
ADHD symptom severity (as assessed by the Amen questionnaire) in ADHD subjects. Although the exact cause of these variations
is unknown, both environmental and genetic factors may be involved. 相似文献
15.
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
16.
Effects of eicosapentaenoic acid and docosahexaenoic acid on plasma membrane fluidity of aortic endothelial cells 总被引:10,自引:0,他引:10
We investigated the relative effects of n−3 eicosapentaenoic acid (EPA, 20∶5n−3) and docosahexaenoic acid (DHA, 22∶6n−3) on
the plasma membrane fluidity of endothelial cells (EC) cultured from the thoracic aorta by determining fluorescence polarization
of 1,6-diphenyl-1,3,5-hexatriene (DPH) and its cationic derivative trimethylamino-DPH (TMA-DPH). Fluidity assessed by TMA-DPH
demonstrated no significant differences in plasma membranes of vehicle (dimethyl sulfoxide; DMSO)-, EPA-, and DHA-treated
EC. Plasma membrane fluidity assessed by DPH polarization, however, was significantly higher in the order of DHA>EPA>DMSO.
Total cholesterol content decreased significantly by 28.4 and 15.9% in the plasma membranes of DHA- and EPA-treated cells,
respectively. Total phospholipid content remained unaltered in the plasma membranes of the three groups of cells; however,
the molar ratio of total cholesterol to phospholipid decreased significantly only in the membranes of DHA-treated EC. The
unsaturation index in the plasma membranes of EPA- and DHA-treated cells increased by 35.7 and 64.3%, respectively, compared
with that in the plasma membranes of control cells. The activities of catalase and glutathione peroxidase in the whole-cell
homogenates, and levels of lipid peroxides in either the whole-cell homogenates or in plasma membrane fractions were not altered
in EPA- or DHA-treated EC. These results indicate that the influence of DHA is greater than that of EPA in increasing plasma
membrane fluidity of vascular EC. We speculate that the greater effect of DHA compared to EPA is due to its greater ability
to decrease membrane cholesterol content or the cholesterol/phospholipid molar ratio, or both, and also to its greater ability
in elevating the unsaturation index in the plasma membranes of EC. 相似文献
17.
In this study, a new marine oil that contains 45% docosahexaenoic acid (DHA, 22∶6n−3) and 13% docosapentaenoic acid (DPA,
22∶5n−6) was administered to rats. The metabolism and distribution of DPA in rats was investigated. In experiment 1, the effects
of DHA and n−6 fatty acids (linoleic acid, I A; arachidonic acid, AA; and DPA) on AA contents were investigated in vivo. LA group: LA 25%, DHA 30%; LA-DPA group: LA 15%, DPA 10%, DHA 35%; LA-AA-DPA group: LA 10%, AA 5%, DPA 10%, DHA 35% were
administered to rats for 4 wk. In the liver, the AA content in the LA-DPA and LA-AA-DPA groups was significantly higher than
in the LA group. The decreased AA contents in the LA group might be caused by DHA administration. Although DHA also was administered
in the LA-DPA and LA-AA-DPA groups, the AA contents in these two groups did not decrease. These results suggested that DPA
retroconverted to AA, blunting the decrease in AA content caused by DHA administration. To conduct a detailed investigation
on DPA metabolism and its relation with AA and DHA, rat hepatocytes were cultured with pruified DPA and DHA for 24 h. We discovered
the retroconversion of DPA to AA occurred only when AA content was decreased by a high DHA administration; it did not occur
when AA content was maintained at a normal level. 相似文献
18.
The aim of this study was to investigate the possibility of a relationship between plasma homocysteine (Hcy) and phospholipid
FA (PUFA) in healthy Australian males. One hundred thirty six healthy male subjects aged 20–55 yr were recruited from the
Melbourne metropolitan area. Each volunteer completed a semiquantitative food frequency questionnaire and gave a blood sample.
Plasma Hcy concentrations were determined by an established HPLC method; the plasma phospholipid FA were determined by standard
methods. Plasma Hcy concentration was significantly negatively correlated with plasma phospholipid concentration of the PUFA
20∶5n−3 (r=−0.226, P=0.009), 22∶5n−3 (r=−0.182, P=0.036), 22∶6n−3 (r=−0.286, P=0.001), total n−3 (r=−0.270, P=0.002) and the ratio n−3/n−6 PUFA (r=−0.265, P=0.002), and significantly positively correlated with 20∶4n−6 (r=0.180, P=0.037). In the partial correlation analysis, after controlling for serum vitamin B12 and folate concentration, plasma Hcy was significantly negatively correlated with the plasma phospholipid concentration of
22∶6n−3 (r=−0.205, P=0.019), total n−3 (r=−0.182, P=0.038) and the ratio n−3/n−6 PUFA (r=−0.174, P=0.048). Evidence indicates that an increased concentration of n−3 PUFA in tissues has a beneficial effect on cardiovascular
health. Our findings provide further evidence that increased consumption of dietary n−3 PUFA increases the concentration of
n−3 PUFA in plasma phospholipid, which is associated with a protective effect on cardiovascular diseases and lower plasma
Hcy levels. The mechanism that might explain the association between plasma 22∶6n−3 and Hcy levels is not clear. 相似文献
19.
Absorption of long-chain polyunsaturated fatty acids from human milk and formula supplemented with fish oil was studied to
determine if the distribution route into lymphatic triacylglycerol (TAG) and phospholipid (PL) varies with the dietary source.
Rats were intraduodenally infused with human milk or formula containing graded amounts of fish oil (0, 0.5, or 1.0 g/100 mL),
and the mesenteric lymph was collected. Arachidonic acid (20∶4n−6) levels in lymphatic TAG and PL were highest from animals
fed human milk. In the animals infused with formula containing fish oil, as the amount of eicosapentaenoic acid (EPA, 20∶5n−3)
infused increased, there was essentially an equal increase of EPA associated with both lymphatic TAG and PL. Animals intraduodenally
infused with human milk or formula without fish oil had only minor levels (less than 1%) of EPA in the lymph. In the fish
oil-treated animals, as the amount of docosahexaenoic acid (DHA, 22∶6n−3) infused increased, there was a 16-fold increase
in DHA associated with lymphatic TAG, but only a 3-fold increase in DHA associated with lymphatic PL. The highest level of
DHA in rats infused with human milk was observed in lymphatic PL. Hence, fish oil can be added to formula as a source of long-chain
polyunsaturated fatty acids, but the distribution of fatty acids into lymphatic TAG and PL is not the same as that observed
with human milk. 相似文献
20.
Fish consumption is associated with reduced cardiovascular mortality, and elevated myocardial long-chain n−3 polyunsaturated
FA (PUFA) content is implicated in this cardioprotection. This study examined the dose and time responses for incorporation
of n−3 PUFA into cellular membranes in rats fed fish oil (FO)-containing diets. For the time course study, rats were fed a
10% FO diet for periods ranging from 0 to 42 d, after which myocardial and erythrocyte membrane fatty acid composition was
determined. For the dose response study, rats (n=3) were fed 0, 1.25, 2.5, 5, or 10% FO for 4 wk, with myocardial, erythrocyte, and skeletal muscle membrane FA determined.
Myocardial DHA (22∶6n−3) levels doubled in 2 d, stabilizing at levels ≈200% higher than control after 28 d feeding with 10%
FO. By comparison, DHA levels doubled after 4 wk of 1.25% FO feeding. In myocardium and skeletal muscle, EPA (20∶5n−3) levels
remained low, but in erythrocytes EPA levels reached 50% of DHA levels. The n−3 PUFA were incorporated at the expense of n−6
PUFA in myocardium and skeletal muscle, whereas erythrocytes maintained arachidonic acid levels, and total n−3 PUFA incorporation
was lower. This study shows that low doses of FO produce marked changes in myocardial DHA levels; maximal incorporation takes
up to 28 d to occur; and while erythrocytes are a good indicator of tissue n−3 incorporation in stable diets, they vary greatly
in their time course and pattern of incorporation. 相似文献