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1.
We have studied the effect of various diets on the phospholipid fatty acid composition andin vitro Δ5 desaturase activity of hepatic microsomes derived either from the normal or streptozotocin-induced diabetic rat. The diets
studied were the standard rat chow diet and a basal fat-free diet supplemented either with 20 percent saturated fat, 20 percent
unsaturated fat, or 20 percent menhaden oil. Phospholipid fatty acid composition analysis revealed that the normal rat fed
the saturated fat or menhaden oil diet had significantly decreased arachidonate levels, consistent with decreased Δ5 desaturase
activities and decreased 18∶2n−6 intake. On the contrary, the unsaturated fat diet decreased dihomo-γ-linolenate and increased
arachidonate levels, without increased Δ5 desaturase activity. Streptozotocininduced diabetes resulted in decreased arachidonate
and Δ5 desaturase activity. The unsaturated fat diet fed to the diabetic rat also failed to correct this decreased Δ5 desaturase
activity. The unsaturated fatty acids in this diet also displaced a substantial amount of n−3 fatty acids in both normal and
diabetic microsomes, due to the competition between these two fatty acid families for incorporation into the membrane phospholipids.
Conversely, the menhaden oil diet fed to the normal and diabetic rats displaced n−6 fatty acids, reduced Δ5 desaturase activity,
and enhanced 22∶6n−3 incorporation into diabetic microsomes. 相似文献
2.
Guinea pigs were fed one of three diets containing 10% black currant seed oil (a source of gamma-linolenic (18∶3 n−6) and
stearidonic (18∶4 n−3) acids), walnut oil or lard for 40 days. The fatty acid composition of liver triglycerides, free fatty
acids, cholesteryl esters, phosphatidylinositol, phosphatidylserine, cardiolipin, phosphatidylcholine and phosphatidylethanolamine
were determined.
Dietary n−3 fatty acids found esterified in liver lipids had been desaturated and elongated to longer chain analogues, notably
docosapentaenoic acid (22∶5 n−3) and docosahexaenoic acid (22∶6 n−3). When the diet contained low amounts of n−6 fatty acids,
proportionately more of the n−3 fatty acids were transformed. Significantly more eicosapentaenoic acid (EPA) (20∶5 n−3) was
incorporated into triglycerides, cholesteryl esters, phosphatidylcholine and phosphatidylethanolamine of the black currant
seed oil group compared with the walnut oil group.
Feeding black currant seed oil resulted in significant increases of dihomogamma-linolenic acid (20∶3 n−6) in all liver lipid
classes examined, whereas the levels of arachidonic acid (20∶4 n−6) remained relatively stable. The ratio dihomo-gamma-linolenic
acid/arachidonic acid was significantly (2.5-fold in PI to 17-fold in cholesteryl esters) higher in all lipid classes from
the black currant seed oil fed group. 相似文献
3.
The effect of very low levels of dietary long-chain n−3 fatty acids on Δ6 desaturation of linoleic acid (18∶2n−6) and α-linolenic
acid (18∶3n−3), and on Δ5 desaturation of dihomo-γ-linolenic acid (20∶3n−6), in liver microsomes and its influence on tissue
fatty acids were examined in obese and lean Zucker rats and in Wistar rats. Animals fed for 12 wk a balanced diet containing
ca. 200 mg of long-chain polyunsaturated n−3 fatty acids per 100 g of diet were compared to those fed the same amount of α-linoleic
acid. Low amounts of long-chain n−3 fatty acids greatly inhibited Δ6 desaturation of 18∶2n−6 and Δ5 desaturation of 20∶3n−6,
while Δ6 desaturation of 18∶3n−3 was not inhibited in Zucker rats and was even stimulated in Wistar rats. Inhibition of the
biosynthesis of long-chain n−6 fatty acids was reflected in a decrease in arachidonic acid (20∶4n−6) content of serum lipids
when fasting, and also in the phospholipid fatty acids of liver microsomes. On the contrary, heart and kidney phospholipids
did not develop any decrease in 20∶4n−6 during fish oil ingestion. Docosahexaenoic acid (22∶6n−3), present in the dietary
fish oil, was increased in serum lipids and in liver microsome, heart, and kidney phospholipids. 相似文献
4.
Menhaden oil (MO), whose polyunsaturated fatty acids consist mainly of (n−3) fatty acids, was fed to spontaneously hypertensive
rats to determine the effect of (n−3) fatty acid on the in vitro production of prostaglandins produced from arachidonic acid
(20∶4[n−6]). Capacity to form PGE2 and PGF2α was impaired in homogenates of kidney medullae and cortices from rats fed the MO diet compared to rats fed the control diet.
The lower amounts of diene prostaglandins produced corresponded to the decrease in the amount of 20∶4 (n−6) in the tissue.
Possibly changes produced in tissue lipids by dietary fatty acids affect prostaglandin production by reducing the availability
of substrate in tissue lipids. 相似文献
5.
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
6.
The sciatic nerve of rats fed sunflower oil (6 mg 18∶3n−3/100 g of diet) presented dramatic alterations in the long chain
polyunsaturated fatty acids in comparison with those fed soy oil (130 mg 18∶3n−3/100 g of diet). In both 15-day-old and 60-day-old
animals fed sunflower oil, 22∶6n−3 (cervonic acid) was fourfold less, 22∶5n−6 was 10-fold greater; adrenic acid (22∶4n−6)
was slightly greater and arachidonic acid (20∶4n−6) was close to that in rats fed soy oil. The percentage distribution of
total polyunsaturated fatty acids as well as the individual saturated and monounsaturated fatty acids were the same in both
groups.
When the sunflower oil-fed animals were switched to a soy oil-containing diet for either 15 or 60 days, the percentage distribution
of 22∶6n−3 increased slowly to reach the control value 2.5 months later. Conversely 22∶5n−6 decreased slowly. The decay of
22∶5n−6 was more rapid than the increase of 22∶6n−3. 相似文献
7.
This study evaluated the effects of conjugated linoleic acids (CLA) on tissue fatty acid composition and ex vivo prostaglandin E2 (PGE2) production in rats given diets varying in n-6 and n-3 fatty acids. Four groups of rats were given a basal semipurified diet
(AIN-93G) containing 70 g/kg of added fat for 42 d. The fat treatments were formulated to contain CLA (0 vs. 10 g/kg of diet)
and n-6 (soybean oil having an n-6/n-3 ratio of 7.3) and n-3 fatty acids (menhaden oil+safflower oil having an n-6/n-3 ratio
of 1.8) in different ratios in a 2×2 factorial design. Fatty acids in liver, serum, muscle, heart, brain, spleen, and bone
(cortical, marrow, and periosteum) were analyzed by capillary gas-liquid chromatography. The various dietary lipid treatments
did not affect growth; however, CLA improved feed efficiency. The CLA isomers were found in all rat tissues analyzed although
their concentrations varied. Dietary CLA decreased the concentrations of 16∶1n−7, 18∶1, total monounsaturates and n−6 fatty
acids, but increased the concentrations of n−3 fatty acids (22∶5n−3 and 22∶6n−3), and saturates in the tissues analyzed. Ex vivo PGE2 production in bone organ culture was decreased by n−3 fatty acids and CLA. We speculate that CLA reduced the concentration
of 18∶1 fatty acids by inhibiting liver Δ9-desaturase activity. The fact that CLA lowered ex vivo PGE2 production in bone organ culture suggests that these conjugated fatty acids have the potential to influence bone formation
and resorption. 相似文献
8.
Svend G. Kaasgaard Gunhild Hølmer Carl-Erik Høy Willy A. Behrens Joyce L. Beare-Rogers 《Lipids》1992,27(10):740-745
Diets rich in linoleic acid (CO) from corn oil, or in linoleic acid and either α-linolenic acid (LO) based on linseed oil
or n−3 fatty acids (MO) from menhaden oil were fed to male and female Cynomolgus monkeys for 15 wk. In the liver a 40% reduction
of α-tocopherol occurred in the MO group relative to the CO and LO groups followed by increased formation of lipofuscinin vivo. A four-fold increase of α-tocopherol in the MO diet (MO+E) brought the level in the liver to that found with CO and LO.
The increased peroxidation in the MO group in the liver phospholipids was associated with the replacement of 60% of the n−6
fatty acids by n−3 fatty acids from menhaden oil. Similar fatty acid profiles were found in groups fed MO and MO+E, respectively.
Compared to the CO fed group, feeding α-linolenic acid only resulted in a slight incorporation of n−3 fatty acids in the liver
membranes mainly due to a direct incorporation of α-linolenic acid. However, in monkeys fed menhaden oil more than 30% of
the total fatty acids in the liver phospholipids were n−3 fatty acids. The various diets did not influence the activity of
liver catalase (EC 1.11.1.6) nor superoxide dismutase (EC 1.15.1.1), but glutathione-peroxidase activity (EC 1.11.1.9) was
higher in monkeys fed the MO diet. The catalase activity in females was 20% higher than in males. In anin vitro assay, liver microsomes from monkeys fed the MO diet or the MO diet supplemented with tocopherol produced similar amounts
of thiobarbituric acid reactive substances and at a much higher rate than microsomes from the CO and LO groups. It appeared
that α-tocopherol did not protect long-chain n−3 C20 and C22 fatty acids as well as n−6 fattya acids against peroxidation. The present data showed that monkeys were not fully able to
compensate for increased peroxidative stress but a four-fold supplement of vitamin E to the diets reduced the oxidation. 相似文献
9.
Effect of dietary n−3 and n−6 polyunsaturated fatty acids on lipid-metabolizing enzymes in obese rat liver 总被引:2,自引:0,他引:2
Isabelle Niot Joseph Gresti Jacqueline Boichot Georges Semporé Georges Durand Jean Bézard Pierre Clouet 《Lipids》1994,29(7):481-489
This study was designed to examine whether n−3 and n−6 polyunsaturated fatty acids at a very low dietary level (about 0.2%)
would alter liver activities in respect to fatty acid oxidation. Obese Zucker rats were used because of their low level of
fatty acid oxidation, which would make increases easier to detect. Zucker rats were fed diets containing different oil mixtures
(5%, w/w) with the same ratio of n−6/n−3 fatty acids supplied either as fish oil or arachidonic acid concentrate. Decreased
hepatic triacylglycerol levels were observed only with the diet containing fish oil. In mitochondrial outer membranes, which
support carnitine palmitoyltransferase I activity, cholesterol content was similar for all diets, while the percentage of
22∶6n−3 and 20∶4n−6 in phospholipids was enhanced about by 6 and 3% with the diets containing fish oil and arachidonic acid,
respectively. With the fish oil diet, the only difference found in activities related to fatty acid oxidation was the lower
sensitivity of carnitine palmitoyltransferase I to malonyl-CoA inhibition. With the diet containing arachidonic acid, peroxisomal
fatty acid oxidation and carnitine palmitoyltransferase I activity were markedly depressed. Compared with the control diet,
the diets enriched in fish oil and in arachidonic acid gave rise to a higher specific activity of aryl-ester hydrolase in
microsomal fractions. We suggest that slight changes in composition of n−3 or n−6 polyunsaturated fatty acids in mitochondrial
outer membranes may alter carnitine palmitoyltransferase I activity. 相似文献
10.
Cynomolgus monkeys were fed oils high in linoleic acid or with half of the linoleic acid replaced by either (n−3) linolenic
acid or marine fatty acids. When the diet contained similar quantities of linoleic and (n−3) linolenic acid, erythrocyte fatty
acids maintained a ratio of (n−6) to (n−3) fatty acids of approximately 2∶4. Fatty acids from menhaden oil enhanced the incorporation
of eicosapentaenoic and docosahexaenoic acids into the monkey erythrocytes, the composition of which was not altered by additional
α-tocopherol. 相似文献
11.
The effect of dietary n−3 fatty acids on prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) levels in rat salivary glands and gingiva was examined in two separate nutritional studies. In the first set of experiments,
two groups of male weanling Sprague-Dawley rats were fed semipurified diets containing 10% corn oil (control group) or 10%
menhaden oil (experimental group). Rats were killed after 8 wk on the diets; the fatty acid composition of total phospholipids
and the concentrations of PGE2 and its precursor, arachidonic acid, were measured in gingiva and submandibular salivary glands (SMSG). Dietary n−3 fatty
acids were incorporated into the tissue phospholipids. Arachidonic acid levels were reduced by 56% in gingiva and SMSG of
rats fed menhaden oil compared with the control rats fed the diet containing corn oil. The concentrations of PGE2 in SMSG and gingiva of rats fed the diet containing menhaden oil were reduced by 74% and 83%, respectively. In a subsequent
nutritional study, we tested whether the diet-induced reduction in tissue arachidonic acid levels would also result in a corresponding
decrease in LTC4 production. Three groups of rats were fed diets containing 5% corn oil (group 1), 4% ethyl ester concentrate of n−3 fatty
acids plus 1% corn oil (group 2), or 5% ethyl ester concentrate of n−3 fatty acids (group 3). After 6 wk of feeding, gingiva
and SMSG were analyzed for arachidonic acid content andin vitro production of LTC4. Arachidonic acid content of total phospholipids was about 60% lower in gingiva and 69% lower in SMSG of rats fed the ethyl
ester concentrate of n−3 fatty acids (groups 2 and 3) than those of the control group fed the corn oil diet (group 1). Upon
incubation with calcium ionophore, gingiva and SMSG from rats fed the n−3 fatty acids rich diet produced significantly less
TLC4 than those from rats of the control group. Because PGE2 and LTC4 are believed to be important biochemical mediators of periodontal disease, one may speculate that a diet-induced reduction
in their levels may have a beneficial effect upon the course of the disease. The function of salivary glands may also be altered
because of the role of these eicosanoids in salivary secretions.
Presented in part for the Hatton Award Competition at the American Association for Dental Research Meeting, San Francisco,
California, March 15–19, 1989, and at the International Association for Dental Research Meeting, Acapulco, Mexico, April 17–21,
1991. 相似文献
12.
The present study was designed to investigate the metabolism of the n−3 olyunsaturated fatty acids (PUFA) in adipose tissue
and its dependence upon dietary factors. Changes in the positional distribution of the fatty acids in triacylglycerols from
retroperitoneal adipose tissue were studied as a function of time on rats fed for 4 wk a diet enriched with fish oil. The
stereospecific analysis of triacylglycerols was based on random formation ofrac-1,2-diacylglycerols by Grignard degradation. This was followed by synthesis ofrac-phosphatidic acids and treatment with phospholipase A2. In the triacylglycerols of the fish oil diet, 57% of the total n−3 fatty acids were in position 3,i.e., two-thirds of 22∶5n−3 and 22∶5n−3 were esterified insn-3 position, whereas 22∶6n−3 was equally distributed in positions 2 and 3. After 4 wk of feeding fish oil, the fatty acid
composition of adipose tissue triacylglycerols reached a steady state. Half of the n−3 fatty acids were found in position
3, namely 75% of 22∶5n−3, 50% of 20∶5n−3 and 18∶4n−3 and 45% of 22∶6n−3, the latter being equally distributed in positions
2 and 3. This pattern of distribution resembled that found in triacylglycerols of the fish oil diet, except for a higher proportion
of 20∶5n−3 in adipose tissue in position 1 at the expense of position 3. Throughout the 4-wk period of fish oil feeding, the
distribution pattern of minor n−3 fatty acids (18∶4n−3 and 22∶5n−3) in adipose tissue triacylglycerols remained unchanged.
On the other hand, at the onset of fish oil feeding, 20∶5n−3 and 22∶6n−3 became concentrated in position 3, but thereafter
20∶5n−3 was progressively incorporated into position 1 and 22∶6n−3 into position 2. We thus conclude that n−3 fatty acids
are differentially esterified in triacylglycerols of white adipose tissue. Despite the complex sequence of hydrolysis and
acylation steps involved, the positional distribution of n−3 fatty acids was found to be similar in both the fish oil diet
and the stored fat, in contrast to what was observed for nonessential fatty acids. 相似文献
13.
P. E. Wainwright Y. S. Huang D. E. Mills G. R. Ward R. P. Ward D. McCutcheon 《Lipids》1989,24(12):989-997
This study assesses the combined effects on brain and behavioral development of ethanol administration and supplementation
of the maternal diet with long chain n−3 polyunsaturated fatty acids. From day 7 to 17 of gestation, pregnant mice were fed
equivalent daily amounts of isocaloric liquid diets; 20% of the energy was provided by either ethanol or maltose-dextrin,
and a further 20% by either safflower oil (rich in linoleic acid, 18∶2n−6), or a combination of safflower oil with a fish
oil concentrate (rich in eicosapentaenoic acid, 20∶5n−3, and docosahexaenoic acid, 22∶6n−3). On day 18 the liquid diets were
replaced by lab chow; a fifth group was maintained on lab chow throughout the experiment. Measures on the pups included brain
weight and the fatty acid composition of the brain phospholipids on days 22 and 32 post-conception (birth=day 19), as well
as behavioral development. Maternal weight gain during gestation was decreased by ethanol relative to maltose-dextrin, and
increased by fish relative to safflower oil. On day 32, the brain weight of ethanoltreated animals fed fish oil was greater
than their safflower oil controls, whereas the reverse was true in the two maltose-dextrin groups; a similar trend was apparent
on day 22. The brain phospholipid content of the longer chain fatty acids (20∶4n−6, 22∶4n−6, 22∶5n−6, 20∶5n−3, 22∶5n−3, 22∶6n−3)
on day 22 reflected that of the prenatal diet, with the proportion of n−3 compounds being higher and that of n−6 floer in
the fish oil than safflower oil groups. Prenatal dietary effects were absent by day 32, with the exception of lower 22∶5n−6
in fish oil groups. Dietary supplementation with n−3 fatty acids increased the ratio of 20∶3n−6 to 20∶4n−6, which is consistent
with a blockade of the activity of Δ-5 desaturase. On day 22 the incorporation of dietary long chain n−3 fatty acids into
the brain phosphatidylcholine fraction was enhanced in the ethanol-treated animals; by day 32 the animals treated prenatally
with ethanol also showed increased levels of long chain n−6 compounds. Behavioral development was retarded by ethanol, but
there was no effect of the dietary oils. These results support the hypothesis that effects of ethanol on the developing brain
may be modified by the availability of an exogenous supply of long chain fatty acids. 相似文献
14.
The purpose of this study was to examine the influence of long-term feeding of dietary fat rich in either n−3 or n−6 fatty
acids on the availability of arachidonic acid (20∶4n−6) in major phospholipids of gastric mucosa in rats. Three groups of
male Wistar rats were fed either a standard diet, a cod liver oil-enriched diet (10% by weight), or a corn oil-enriched diet
(10% by weight) for 8 mon. Dietary cod liver oil significantly reduced the level of 20∶4n−6 in phosphatidylcholine (PC) and
in phosphatidylethanolamine (PE) of gastric mucosa. The loss of 20∶4n−6 was compensated for by eicosapentaenoic acid (20∶5n−3)
in PC, whereas the decrease in 20∶4n−6 in PE corresponded to the increase in three n−3 fatty acids: 20∶5n−3, docosapentaenoic
acid (22∶5n−3), and docosahexaenoic acid (22∶6n−3). The level of 20∶5n−3 was higher than the level of 22∶6n−3 both in PC and
PE of mucosa in rats fed cod liver oil. Diets supplemented with corn oil increased the level of 18∶2n−6 but decreased the
monoene fatty acids 16∶1 and 18∶1n−7 in PC but not in PE of gastric mucosa. The 20∶4n−6 levels of both PC and PE were markedly
reduced by dietary cod liver oil, to about one-third of control levels. Similar changes were also observed in the stomach
wall. Gastric erosions were observed in all rats exposed to restriction stress, but this form of stress induced twice the
number of erosions in rats fed fish oil compared to control rats or rats fed corn oil. We conclude that a diet rich in fish
oil altered the balance between n−6 and n−3 fatty acids in major gastric mucosal phospholipids, markedly reduced the availability
of 20∶4n−6, and increased the incidence of gastric erosions induced by restriction or emotional stress. 相似文献
15.
The effects of dietary n−3 and n−6 polyunsaturated fatty acids on the fatty acid composition of phospholipid, Ca++· Mg++ ATPase and Ca++ transport activities of mouse sarcoplasmic reticulum were investigated. Mice were fed a 2 weight percent fat diet containing
either 0.5 weight percent ethyl esters of 18∶3n−3, 20∶5n−3 or 22∶6n−3 as a source of n−3 polyusaturated fatty acid or 0.5
weight percent safflower oil as a cource of n−6 polyunsaturated fatty acid for 10 days. Olive oil (2 weight percent) was used
as a control diet. Although feeding n−6 polyunsaturated fatty acid induced very little modifications of the phospholipid sarcoplasmic
reticulum fatty acid composition, feeding n−3 polyunsaturated fatty acid altered it markedly. Inclusion of 18∶−3, 20∶5n−3
or 22∶6n−3 in the diet caused an accumulation of 22∶6n−3, which replaced 20∶4n−6 and 18∶2n−6 in phospholipid sarcoplasmic
reticulum. The saturated fatty acids were significantly increased with a concurrent reduction of 18∶1n−9. These changes in
the fatty acid composition resulted in a decrease in the values of the n−6/n−3 polyunsaturated fatty acid ratio and a decrease
in the ratio of 20 carbon to 22 carbon fatty acids esterified in the phospholipid sarcoplasmic reticulum. This was associated
with a decrease in Ca++ uptake by n−3 polyunsaturated fatty acid enriched sarcoplasmic reticulum vesicles as compared with n−6 fatty acid and control
diet sarcoplasmic reticulum vesicles. However, neither the affinity for Ca++ nor the maximal velocity of ATP hydrolysis activity of Ca++·MG++ ATPase were altered by the different diets. The data suggest that the incorporation of 22∶6n−3 and/or the decrease of 20∶4n−6
plus 18∶2n−6 in the phospholipid sarcoplasmic reticulum may affect the membrane lipid bilayer structure and make it more permeable
to Ca++. 相似文献
16.
L. Ulmann J. P. Blond C. Maniongui J. P. Poisson G. Durand J. Bézard G. Pascal 《Lipids》1991,26(2):127-133
The combined effects of age and dietary n−6 and n−3 fatty acids were studied in 3-, 6- and 9-month-old rats. At each age,
two groups were fed diets containing 5% (w/w) of vegetable oils rich in either 18∶3n−6 (borage group) or 18∶3n−6 plus 18∶4n−3
(black currant group), for a period increasing with age. A control group was fed the essential fatty acids 18∶2n−6 and 18∶3n−3
only. For each group, Δ6, Δ5 and δ9 desaturase activities were measured in liver microsomes, and fatty acid composition was
determined in microsomal phospholipids. Desaturase activity varied as a function of age and dietary lipids. Δ6 Desaturation
of 18∶3n−3 was more sensitive to these factors while Δ6 desaturation of 18∶2n−6 and Δ9 desaturation were more dependent on
season than the other two. Desaturase activity was influenced more by the black currant than by the borage diet, especially
at 6 and 9 months of age. A large proportion of arachidonic acid was maintained in the microsomes independent of the diet.
Changes in the fatty acid composition did not strictly reflect the differences in desaturase activities. The effects of the
two factors (age and diet) on the activities of the desaturases are complex, suggesting that the enzymes are susceptible to
other factors as well. 相似文献
17.
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
18.
Docosahexaenoic acid (22∶6n−3) can be synthesized in the liver and/or brain from α-linolenic acid (18∶3n−3) and is required
in large amounts in structural membranes of developing brain and retina. The adequacy and efficacy of formulas containing
18∶3n−3 and/or fish oil in providing 22∶6n−3 for deposition was investigated in piglets fed formula from birth to 15 days.
The test formulas contained high (HL) or low (LL) 18∶3n−3 (3.9 or 0.7% of the total formula fatty acids, respectively), or
low 18∶3n−3 plus fish oil (LL+FO) to provide C20 and C22 n−3 polyunsaturated fatty acids (0.8% of total fatty acids). Fatty acid analyses of synaptic plasma membrane and retina ethanolamine
phospholipids (EPL), which are especially enriched in 22∶6n−3, were compared to those of 15-day-old piglets fed sow milk (SM).
Feeding LL resulted in lower 22∶6n−3 in synaptic plasma membrane. Fatty acid levels in HL and LL+FO piglets were equivalent
to SM, with the exception of lower 22∶5n−3 in the synaptic plasma membrane of LL+FO and in the retina of HL and LL+FO-fed
piglets. Levels of 22∶4n−6 were also lower in the retina of the LL+FO group. The results suggest formula 18∶3n−3 is at least
24% as effective as C20 and C22 n−3 fatty acids as a source of membrane 22∶6n−3. This study shows dietary 18∶3n−3, as the only n−3 fatty acid, can support
deposition of comparable percentage of 22∶6n−3 to natural milk. Fish oil also supported tissue levels of 22∶6n−3 similar to
natural milk; however, lower 22∶4n−6 may indicate possible inhibitory effects on n−6 metabolism.
Recipient of the 1967 Science and Engineering Scholarship, Natural Sciences & Engineering Research Council of Canada. 相似文献
19.
John D. Palombo Erin E. Lydon Pei-Linn Chen Bruce R. Bistrian R. Armour Forse 《Lipids》1994,29(9):643-649
Utilization of enteral feeding modalities may prove clinically relevant for rapid modulation of lung phospholipid polyunsaturated
fatty acids (PUFA) that serve as substrates for the formation of vasoactive dienoic eicosanoids. We compared the effects of
short-term enteral feeding with formulations enriched with either fish (n−3) or corn (n−6) oil PUFA on the fatty acid composition
of rat lung, alveolar macrophage and surfactant phospholipids. The diets were infused continuously for 72 h through a surgically
placed gastroduodenal feeding catheter by a syringe pump. The n−3 PUFA derived from the fish oil enriched diet were readily
incorporated into the phospholipid membranes of the alveolar macrophages, lung tissue and pulmonary surfactant. The relative
percentages of the n−3 PUFA were significantly higher and individual and total n−6 PUFA significantly lower in the macrophage,
lung and surfactant phospholipids from the n−3-supplemented rats in comparison with those present in the rats infused enterally
with the n−6 diet or untreated, chow-fed rats (baseline). In contrast, there was a significant increase in linoleic acid (18∶2n−6)
without modification of arachidonic acid (20∶4n−6) in the alveolar macrophages, lung tissue and surfactant from rats enterally
receiving the n−6 diet relative to levels measured in the rats at baseline. The results suggest that short-term continuous
delivery of n−3-enriched enteral preparations can foster rapid modification of membrane phospholipid PUFA composition of lung
tissue, alveolar macrophages and lung surfactant. Utilization of similar infusion modalities to deliver n−3-enriched enteral
formulations may prove beneficial to critically ill or postoperative patients with persistent lung inflammation secondary
to uncontrolled formation of vasoactive eicosanoids derived from arachidonic acid. 相似文献
20.
Maternally-supplied fish oil alters piglet immune cell fatty acid profile and eicosanoid production 总被引:5,自引:0,他引:5
This study was designed to examine the incorporation of omega-3 (n−3) fatty acids into the immune tissues of pigs nursing
fish oil-fed sows and to determine the effect of maternal dietary n−3 consumption onin vitro immune cell eicosanoid production. On day 107 of gestation, 12 sows were randomly allotted to a diet containing either 7%
menhaden fish oil (MFO) or lard (LRD). The fatty acid profile of serum, liver, thymus, splenocytes and alveolar macrophages
(AM) of 18–21-day-old pigs was significantly affected by the fat source provided to the sow. Arachidonic acid (20∶4n−6) content
was typically reduced by more than 50% in MFO as compared with LRD pigs. In MFO pigs, eicosapentaenoic acid (20∶5n−3) was
the major n−3 polyunsaturated fatty acid, and its levels matched or exceeded those of arachidonic acid. Basal release of prostaglandin
E, thromboxane B and leukotriene B by AM was 60–70% lower in MFOvs. LRD pigs. However, when these immune cells were stimulated with calcium ionophore A23187, release of leukotriene B was similar
in MFO and LRD pigs. In conclusion, substituting MFO for LRD in a sow's late-gestation and lactation diet greatly elevated
the content of n−3 fatty acids in the nursing pig immune cells and generally reducedin vitro eicosanoid release by pig immune cells.
Presented in part at the 1991 Midwest Animal Sciences meeting, Des Moines, Iowa. 相似文献