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1.
Robert A. Gibson Mark A. Neumann Sharon L. Burnard Josephine A. Rinaldi Glen S. Patten Edward J. McMurchie 《Lipids》1992,27(3):169-176
Adult male marmoset monkeys were fed eicosapentaenoic acid (20∶5n−3) as the ethyl ester in diets containing either 32% (reference
diet, no added cholesterol) or 7% (atherogenic diet with 0.2% added cholesterol) linoleic acid (18∶2n−6) for 30 wk. No changes
were seen in the level of phosphatidylcholine (PC) or phosphatidylethanolamine (PE) but minor changes were observed in both
the sphingomyelin (SPM) and phosphatidylinositol plus phosphatidylserine (PI+PS) fractions of erythrocyte lipids. The extent
of total n−3 fatty acid incorporation into membrane lipids was higher in atherogenic diets (polyunsaturated/monounsaturated/saturated
(P/M/S) ratio 0.2∶0.6∶1.0) than reference diets (P/M/S ratio 1∶1∶1) and this was true for both PE (33.4±1.0%vs 24.3±1.1%) and PC (9.3±0.5%vs 4.9±0.3%). Although suitable controls for cholesterol effects were not included in the study, earlier results obtained with
marmosets lead us to believe such effects were probably small. Regardless of basic diet (atherogenic, reference), 20∶5n−3
was preferentially incorporated into PE (10.8±0.2%, 6.0±0.02%) while smaller amounts were incorporated into PC (6.9±0.4%,
3.2±0.2%). The major n−3 polyunsaturated fatty acid found in PE in response to dietary 20∶5n−3 was the elongation metabolite
22∶5n−3 in both the atherogenic (17.7±0.7%) and reference (14.3±1.0%) dietary groups; 22∶6n−3 levels were less affected by
diet (4.7±0.3% and 3.9±0.2%, respectively). The results can be interpreted to indicate an inverse relationship between the
amount of dietary 18∶2n−6 and incorporation of 20∶5n−3 into erythrocyte membrane phospholipids regardless of whether the major
dietary n−3 fatty acid was α-linolenate (18∶3n−3) or 20∶5n−3. This interpretation is supported by theoretical calculations. 相似文献
2.
Diets in which both the lipid content and composition (polyunsaturated to saturated fatty acid ratio) were varied were fed
to rats for 20 weeks, and the effects on the tissue lipid profiles were determined. The fatty acid profile of the plasma lipids,
and the phospholipid fatty acids of the mitochondrial and microsomal fractions of liver, heart, kidney and brain, as well
as erythrocyte membranes were determined. Despite large differences in the level and type of lipid present in the experimental
diets and in the proportion of saturated fatty acids in the plasma lipids in response to the various diets, there was little
effect on the proportion of saturated to unsaturated fatty acids in the phospholipids of the various membranes examined. The
major effect of altering the dietary level of polyunsaturated to saturated fatty acids was on the ratio of the ω6/ω3 series
of unsaturated fatty acids in the membrane lipids. This change occurred in all tissues except the brain, in which only a small
response to altered dietary lipid intake was observed. The ω6/ω3 ratio was elevated upon feeding a diet rich in ω6 polyunsaturated
fatty acids, but decreased when a diet rich in saturated fatty acids was fed. The failure to significantly alter membrane
lipid saturation/unsaturation in the tissues examined would suggest that a homeostatic mechanism is operative in biological
membranes and may act to buffer membranes from the effects of changes in the nature of the dietary lipid intake. 相似文献
3.
Nine healthy male volunteers were given 15 Max EPA fish oil capsules providing 2.67 g of eicosapentaenoic acid (EPA, 20∶5ω3)
and 1.72 g of docosahexaenoic acid (DHA, 22∶6ω3) daily for 3 wk. Measurements were taken at baseline, at the end of the fish-oil
period, and at 2 and 6 wk postsupplementation. The effect of fish oil on plasma lipids and the fatty acid composition of individual
platelet phospholipids was studied. In general, the proportions of 20∶5ω3 and 22∶6ω3 in platelet phosphoglycerides were substantially
increased mainly at the expense of arachidonic acid (AA, 20∶4ω6). A large and significant increase in the relative EPA content
of phosphatidylcholine (PC) (P<0.001) and phosphatidylethanolamine (PE) (P<0.001) was noted at the end of the 3 wk supplementation.
We have also shown for the first time a small but significant (P<0.001) incorporation of EPA in phosphatidylserine (PS). Incorporation
of DHA was also detected in PC, PE and PS, whereas the relative AA content of these phospholipids was significantly reduced.
Fish oil supplementation led to a significant increase of 22∶5ω3 in PS and decreases of 20∶3ω6 in PC and 22∶4ω6 in PE. Postsupplementation
measurements showed a gradual return of all fatty acids to baseline levels. The fatty acid composition of the phosphatidylinositol
(PI) fraction remained unchanged throughout the trial period. We conclude that in humans ω3 fatty acids are incorporated into
platelet membrane phospholipid subclasses with a high degree of specificity. 相似文献
4.
The effect of various dietary fats on membrane lipid composition, fatty acid profiles and membrane-bound enzyme activities
of rat cardiac sarcolemma was assessed. Four groups of male weanling Charles Foster Young rats were fed diets containing 20%
of groundnut, coconut, safflower or mustard oil for 16 weeks. Cardiac sarcolemma was prepared from each group and the activities
of Na+,K+-ATPase, 5′-nucleotidase, Ca2+-ATPase and acetylcholinesterase were examined. ATPase activities were similar in all groups except the one fed coconut oil,
which had the highest activities. Acetylcholinesterase activity was also similar in all the groups, however, it was significantly
higher in the group fed mustard oil. No significant changes were observed among the groups in 5′-nucleotidase activity, in
the cholesterol-to-phospholipid molar ratio and in sialic acid content. The coconut, safflower and mustard oil diets significantly
increased cholesterol and phospholipid contents and the lipid-to-protein ratio of cardiac sarcolemma as compared to feeding
the groundnut oil diet. The fatty acid composition of membrane lipids was quite different among the various groups, reflecting
the type of dietary fat given. The total unsaturated-to-saturated fatty acid ratio was not different among the various groups;
however, the levels of some major fatty acids such as palmitic (16∶0), oleic (18∶1) and linoleic (18∶2) acids were significantly
different. Cardiac sarcolemma of the group fed safflower oil had the highest polyunsaturated fatty acid content. The results
suggest that dietary fats induce changes not only in the fatty acid composition of the component lipids but also in the activities
of sarcolemmal enzymes involved in the regulation of cardiac function. 相似文献
5.
The effect of subacute toxicity levels of dietary cyclopropenoid fatty acids upon several physiological parameters was determined in the rat. Diets containing 2% corn oil, 2%Sterculia foetida oil or 2% hydrogenatedSterculia foetida oil were fed.Sterculia foetida oil (50% cyclopropenoid fatty acids) fed rats exhibited retarded growth, elevated organ to body wt ratios, increased saturation of tissue lipid, and abnormal histopathology when compared to corn oil and hydrogenatedSterculia foetida oil fed rats. Growth was retarded 50%, liver/body wt doubled, and the percentage of saturated fatty acids in adipose tissue increased 2.5-fold forSterculia foetida oil vs. corn oil comparisons. Three membrane systems were examined in corn oil andSterculia foetida oil fed rats. Erythrocyte hemolysis rate in 0.3 M glycerol was increased by 30%; induction of mitochondrial swelling by reduced glutathione was inhibited completely and microsomal codeine demethylase activity was depressed nearly 50% inSterculia foetida oil fed rats. The ability of cyclopropenoid fatty acids to inhibit fatty acyl desaturase and influence tissue and membrane lipid composition is discussed. Most of the detrimental effects observed in cyclopropenoid fatty acids fed rats may be associated with alteration of normal lipid metabolism and membrane function. 相似文献
6.
L. G. Cleland M. A. Neumann R. A. Gibson T. Hamazaki K. Akimoto M. J. James 《Lipids》1996,31(8):829-837
n-9 Eicosatrienoic acid (ETrA), also known as Mead acid, is a minor fatty acid in essential fatty acid (EFA)-sufficient healthy
subjects but is found at increased levels in EFA deficiency. This study examined the influence of dietary ETrA from a biological
source on plasma and tissue ETrA. A synthetic fat-free diet was prepared to which was added Mut 48 oil which contains 19%
ETrA (wt%) as well as other n-9 fatty acids. Blends of vegetable oils were used to achieve overall diets with 5% fat (wt%)
and varying amounts of ETrA at two different dietary levels of linoleic acid (LA), approximately 4.4 and 19% of total fatty
acids. These diets were fed to 5-week-old Dark Agouti rats for four weeks. Plasma lipid fractions and liver, spleen, and peritoneal
exudate (PE) cells were analyzed for fatty acid composition. ETrA was present at up to 20% total fatty acids in plasma triglyceride,
cholesterol ester, and phospholipid fractions. ETrA also accumulated to substantial levels in phospholipids of liver and spleen
(up to 15% of total fatty acids) and PE cells (up to 11%). ETrA was found in plasma and tissue phospholipids in proportion
to the amount of ETrA present in the diet. The incorporation was reduced in diets with higher LA content compared to diets
containing similar amounts of ETrA but lower LA. All rats remained apparently healthy, and histological survey of major organs
revealed no abnormality. While the long-term implications for health of ingestion of diets rich in ETrA remain to be established,
rats appear to tolerate high levels of dietary ETrA without adverse effects. Dietary enrichment with ETrA warrants further
investigation for possible beneficial effects in models of inflammation and autoimmunity, as well as in other conditions in
which mediators derived from n-6 fatty acids can affect homeostasis adversely. 相似文献
7.
Analyses of the fatty acid content and composition of various lung lipids were conducted in rats 1 day, 5 days, and 12 days
after birth and in adult animals in order to define more clearly the specific lipid peroxidizing system found in neonatal
rat lungs. Lipid peroxidation occurs in the 900×g supernatant fraction of rat lung homogenates in an age-dependent manner
independent of the addition of any factor and is maximal at 5 days of age. No lipid peroxidation is evident in similar preparations
of either newborn or adult lung tissue. As the animals develop, arachidonic and docosahexaenoic acids, fatty acids which are
both highly susceptible to lipid peroxidation in the presence of a suitable catalyst, decrease gradually when measured as
the percentage of the total fatty acids in the triglyceride fraction of the lung. The total quantity of triglycerides, however,
is significantly lower in lungs from 1-day-old rats than at any other age. The fatty acid composition and total quantity of
both lung phospholipids and lung free fatty acids do not show similar changes. Following in vitro incubation of the 900×g
supernatant fraction of peroxidizing lung homogenates, an appreciable decrease in the amount of arachidonic and docosa-hexaenoic
acid could be detected in lung triglycerides. Less extensive decreases were observed in the phospholipid fraction. No changes
in these components were observed in newborn or adult animals. The addition of triarachidonin to the 900×g supernatant fraction
of lung homogenates resulted in increased malondialdehyde release at all ages tested while added arachidonic acid increased
the formation of malondialdehyde only in 5- and 12-day-old rat lung preparations. The addition of triolein, cholesterol arachidonate,
and diarachidonyl phosphatidylcholine had no effect on malondialdehyde formation at any age. The age-dependent lipid peroxidation
observed after in vitro incubation of rat lung homogenate preparations, therefore, may result from the relatively high concentration
of triglycerides containing polyunsaturated fatty acids present in the neonatal tissue. As the susceptible polyunsaturated
fatty acids of lung triglycerides are replaced by less unsaturated species, this activity may diminish concomitantly.
Recipient of Public Heath Service Research Career Development Award 5-K04-HD00068 from the National Institute of Child Health
and Human Development. 相似文献
8.
Effect of dietary columbinic acid on the fatty acid composition and physical membrane properties of different tissues of EFA-deficient rats 总被引:1,自引:0,他引:1
The effect of columbinic acid (5 trans, 9 cis, 12 cis, octadeca-trienoic acid) supplemented to a fat-free diet on the fatty acid composition and its correlation to the physical properties of several tissues of rats, was studied. The absence of lipids in the diet produced the typical changes in the fatty acid composition characteristic of essential fatty acid (EFA) deficiency, namely a significant increase in the relative percentage of monoenoic fatty acids with a concomitant decrease in linoleic and arachidonic acids and a rise in eicosa-5,8,11-trienoic acid in liver, kidney, lung and spleen homogenates. Columbinic acid supplemented to a fat-free diet for 24 or 48 hr was incorporated into the different tissues and was partially elongated to 7 trans, 11 cis, 14 cis eicosatrienoic acid, but it was not desaturated. It modified the fatty acid spectrum of the lipids in the different tissues returning it to a similar composition of non-EFA deficient animals, except for a decrease of linoleic acid. The absence of lipids in the diet produced an increase in the 1-6 diphenyl-1,3,5-hexatriene (DPH) steady-state fluorescence anisotropy (rs) in liver microsomes, that was corrected by the administration of columbinic acid for 24 hr. It is concluded that columbinic acid produced a change in the pattern of total fatty acid composition of the different tissues studied which induced a favorable effect on the physical properties of the liver microsomal membranes (rs), leading to an improvement on the fatty acid deficiency in those membranes. Besides, columbinic acid would also exert a favorable effect in the short term, but not in the long-term eicosanoids production. 相似文献
9.
Response of free and esterified plasma cholesterol levels in the mongolian gerbil to the fatty acid composition of dietary lipid 总被引:2,自引:0,他引:2
The present study was undertaken to investigate the potential suitability of the Mongolian gerbil as a useful animal model
to study the effects of dietary fats on plasma cholesterol levels. Semipurified diets containing either 20% lard, 20% safflower
oil, or 19.5% beef tallow +0.5% safflower oil were equalized to contain 0.01% cholesterol and 0.05% plant sterol and were
fed for a four week experimental period. The proportions of total calories contributed by fat, protein and carbohydrate (starch/sucrose
ratio of 2∶1) were 40, 14 and 46%, respectively, so as to approach the distribution of calories within the average North American
diet. Free, esterified, and total plasma cholesterol levels of male gerbils were determined weekly by gas liquid chromatography
after drawing blood via a serial sampling technique. After 1, 2, 3, and 4 weeks of feeding the experimental diets, total cholesterol
levels were lowest in the safflower oil fed animals; the corresponding values were 19–64% greater in gerbils fed lard and
68–91% greater in those consuming the beef tallow diet. Cholesterol in the free form generally responded more dramatically
to the type of dietary lipid than did cholesterol in the ester form. Irrespective of the type of dietary lipid or the length
of the feeding trial, 18–23% of the total plasma cholesterol was in the free form and 77–82% was present as the ester. In
view of the similarity to the human of the relative proportions of free versus esterified cholesterol, the type of cholesteryl
esters, and their response to dietary manipulation, the gerbil appears to be a useful animal model for studying the regulatory
effect of dietary lipid on plasma cholesterol levels.
Presented in part at the A.O.C.S. Annual Meeting, San Francisco, CA, May 1979. 相似文献
10.
Three isocaloric diets were prepared. Diet 1 (Control) contained 22% herring oil. In diets 2 and 3, a third and a half of
the herring oil was replaced, respectively, by an animal fat (lard) which contained a high percentage of saturated fatty acids.
Each diet was fed to duplicate groups of rainbow trout for 14 wk. The results of the feeding trial indicated that the concentration
of the saturated fatty acids in trout body lipid did not increase despite the high concentration of these fatty acids in Diets
2 and 3. Fish growth, feed efficiency, mortality and the level of fatty acid deposited in fish body lipid and phospholipids
are discussed.
Technical Paper No. 4440, Oregon Agricultural Experiment Station, Oregon State University, Corvallis, OR 97331. 相似文献
11.
The present study was carried out to examine if the positional distribution of medium-chain fatty acid (MCF) in dietary synthetic
fat influences lymphatic transport of dietary fat and the chemical composition of chylomicrons in rats with permanent cannulation
of thoracic duct. Four types of synthetic triacylglycerol were prepared: (i) sn-1(3) MCF-sn 2 linoleic acid, (ii) interesterified sn-1(3) MCF-sn 2 linoleic acid, (iii) sn-2 MCF-sn-1(3) linoleic acid, and (iv) interesterified sn-2 MCF-sn-1(3) linoleic acid. A purified diet composed of equal amounts of the synthetic fat and cocoa butter was given to rats with
permanent lymph duct cannulation. The positional distribution of MCF in the dietary fat had no significant effect on the lymph
flow, triacylglycerol output, phospholipid output, lipid composition of chylomicrons, or the particle size. The positional
distribution of MCF in the synthetic triacylglycerol was maintained in the chylomicron triacylglycerol. These results showed
that MCF in the dietary triacylglycerol is transported into lymphatics and the positional distribution is well preserved in
chylomicron triacylglycerol. 相似文献
12.
The effect of dietary fats on phospholipid class distribution and fatty acid composition was studied in rat fat cell plasma
membrane. Three groups of male Wistar weanling rats were fed for 8 wk three diets differing in the amount and nature of the
fats: 1.5% sunflower oil (low fat control; LFC), 10% sunflower oil (high fat, unsaturated; HFU), 1.5% sunflower oil+8.5% cocoa
butter (high fat, saturated; HFS). Plasma membranes were prepared from epididymal adipocytes. The amount and type of dietary
fat significantly altered membrane phospholipid distribution. Phospholipid content was lowered with HFU as compared to LFC
or HFS diets, but no changes were observed for cholesterol. Phosphatidylinositol (PI) and phosphatidylserine (PS) were less
affected by dietary changes than were other phospholipid classes. Major changes were detected for phosphatidylcholine (PC),
phosphatidylethanolamine (PE) and sphingomyelin (SM) contents. No large changes in PC and PE fatty acid compositions were
observed between the LFC and HFS groups, but the HFU diet induced several changes. Correlations with plasma membrane 5′-nucleotidase
activities are discussed. 相似文献
13.
Alteration in membrane lipid order and composition in metabolically hyperactive fatty rat adipocytes 总被引:2,自引:0,他引:2
Michèle Guerre-Millo Phillipe Guesnet Colette Guichard Georges Durand Marcelle Lavau 《Lipids》1994,29(3):205-209
We have previously shown that adipose cells from young genetically obese Zucker rats are characterized by very high metabolic
activity together with an increase in a wide range of membrane-mediated functions. The aim of the present study was to examine
whether the physical properties of the membranes and the composition of the membrane lipids were altered in these cells. Plasma
membranes and two intracellular membrane fractions were prepared by differential ultracentrifugation from inguinal adipose
cells of 30-day-old obese (fa/fa) and lean (Fa/fa) littermates. The lipid order as measured by steady-state fluorescence polarization
of diphenylhexatriene used as probe was markedly decreased in the plasma membranes of obese rat adipose cells. Consistent
with this, the cholesterol-to-phospholipid ratio was significantly decreased, and the degree of unsaturation of the phospholipid
fatty acids was significantly increased. In intracellular membranes, none of these parameters were altered by the different
genotype. In fat cells from obese rats, both plasma and intracellular membranes exhibited a 2-fold decrease in the ratios
of n−6/n−3 fatty acids mainly due to an enrichment in docosahexaenoic acid (22∶6n−3). The data show that the fatty genotype
is a determinant of membrane lipid order and composition in adipose cells. The alterations reported here for young obese Zucker
rat adipocytes might be related to the metabolic hyperactivity of these cells. 相似文献
14.
A study was made of the influence of semisynthetic diets of low and high unsaturation on the fatty acid composition and desaturation-chain
elongation enzymatic activity of the liver microsomal fractions of male Sprague-Dawley rats of different ages. Groups of rats
were fed 5 or 20% coconut oil (CO), or a 5 or 20% mixture of corn and menhaden oils (3∶7) (CME) from weaning to 100 wk of
age. Growth rate and food consumption were measured during this period in which animals were sacrificed at 36, 57, 77 and
100 wk of age. Both the level and composition of the dietary fat supplements produced marked effects on the fatty acid composition
of the liver microsomal lipids. In general, the fatty acid composition of the microsomal fractions reflected that of the dietary
fat and was more unsaturated with the higher level of fat fed. The rate of conversion of linoleic to arachidonic acid in assays
performed in vitro with liver microsomal preparations from animals of the different groups also showed marked differences.
The 6-desaturase-chain elongation activity was higher in the 5% than 20% group and corresponded to the essential fatty acid
(EFA) status of the animals in these groups as represented by the triene-tetraene ratio of the microsomal lipid. The relationship
of the 6-desaturase activity to fatty acid composition of the microsomal lipid indicated that if varied directly with the
level of 20∶3ω9, 18∶1 and 16∶1 and was inhibited by arachidonic acid. The activity of the 6-desaturase enzyme system was lowest
in the liver microsomal fraction obtained from the animals fed the CME diets and appeared to be suppressed by the high levels
of 20∶5 and 22∶6 that accumulated in the microsomal lipid. Accordingly, the levels of arachidonic acid were lower in the microsomal
lipid of these groups than those of the corresponding CO groups in spite of a greater abundance of linoleic acid in the diet.
The data suggest that the activity of the 6-desaturase-chain elongation system is regulated by the fatty acid composition
of the microsomal lipid as influenced by the composition of the dietary fat. 相似文献
15.
Atlantic salmon post-smolts were fed diets containing either fish oils (Fosol, FO and Marinol, MO) rich in long-chain n-3
polyunsaturated fatty acids (PUFA), or plant oils rich in 18:2n-6 (sunflower oil, SO) or 18:3n-3 (linseed oil, LO) for 12
wk. The major PUFA in individual phospholipids from gill and kidney were related to the dietary lipid intake. Levels of n-6
PUFA were highest while levels of n-3 PUFA were lowest in fish fed SO. Fish fed LO generally had lower levels of 20:4n-6 compared
to the other treatments while fish fed SO generally had the highest levels of 20:4n-6. In all phospholipid classes except
phosphatidylinositol (PI) 20:5n-3 was greatest in fish fed MO followed by FO, LO, and SO. In PI, 20:5n-3 was also highest
in fish fed MO but those fed LO contained more 20:5n-3 than those fed FO. This resulted in the ratio of the eicosanoid precursors,
20:4n-6/20:5n-3, being significantly greater in fish fed SO, for all phospholipid classes, compared to fish fed the other
three dietary oils. The activity of gill phospholipase A was greatest in fish fed FO and was lowest in fish fed SO. The concentration
of PGF3α was significantly increased in gill homogenates from fish fed MO compared to the other three treatments while PGF2α was significantly increased in fish fed SO compared to those fed LO. The concentration of PGE3 was significantly reduced in kidney homogenates from fish fed SO compared to the other three treatments while PGE2 was significantly increased in fish fed SO compared to those fed either FO or LO. 相似文献
16.
Weanling male rats were fed hydrogenated coconut oil to induce essential fatty acid (EFA) deficiency. After 15 weeks, the
rats were divided into six groups. Five groups were fed graded amounts of purified linolenate (18∶3ω3) with a constant amount
of linoleate (18∶2ω6) for six weeks. Fatty acid composition was determined in brain lipids. Increasing dietary 18∶3ω3 resulted
in a decrease in arachidonic acid (20∶4ω6), docosatetraenoic acid (22∶4ω6) and docosapentaenoic acid (22∶5ω6), whereas 18∶2ω6
and eicosatrienoic acid (20∶3ω6) were increased both in total lipids and phospholipids. These results suggest that dietary
18∶3ω3 exerts its inhibitory effect mainly on the desaturation of 20∶ω6 to 20∶4ω6 in brain lipids. Linolenate was undetectable
in brain lipids from any dietary treatments. The levels of eicosapentaenoic acid (20∶5ω3) in groups receiving dietary 18∶3ω3
were not different from that of the group receiving no 18∶3ω3. These results indicate that, in the brain, 18∶3ω3 is rapidly
converted mainly to 22∶6ω3 without being accumulated and imply that dietary 18∶3ω3 can modulate the level of precursor of
diene prostaglandins (PG) but not that of triene PG in the rat brain. 相似文献
17.
Lih-Ling Wang Andrew C. Peng Andrew Proctor 《Journal of the American Oil Chemists' Society》1990,67(8):499-502
Lipids from five cultivars of highbush blueberries (Vaccinium corymbosum L.) were extracted and fractionated into neutral lipids (60–66%), glycolipids (20–22%) and phospholipids (14–18%). The major
fatty acids in all fractions were palmitic (16∶0), oleic (18∶1), linoleic (18∶2), and linolenic (18∶3) acids. All lipid classes
had a large concentration of C18 polyunsaturated acids (84–92%), indicating that blueberries are a rich source of linoleic and linolenic acids. Changes in
the fatty acid composition of neutral lipids and phospholipids were not significantly different among the five cultivars,
but significant differences were noted in the ratios of linoleic and linolenic acids in the glycolipids fraction. 相似文献
18.
The effect of essential fatty acid (EFA) deficiency on the lipid composition of basolateral plasma membranes (BPM) from intestinal
mucosal cells was investigated in weaning pigs fed control or EFA-deficient diets for 12 weeks. The phospholipid and cholesterol
contents relative to protein were similar in both groups, showing a cholesterol/phospholipid molar ratio of 0.6. The distribution
of phospholipid classes was also unaffected by the diet. In contrast, fatty acid profiles of the two phospholipid main classes,
phosphatidylcholine and phosphatidylethanolamine were altered by EFA deficiency. Linoleic acid (18∶2n−6) was largely reduced,
whereas arachidonic acid (20∶4n−6) only slightly decreased in EFA-deficient pigs. The unsaturation index was essentially maintained
by high levels of oleic acid (18∶1n−9) and by conversion of oleic acid to 5,8,11-eicosatrienoic acid (20∶3n−9). Finally, during
the period of EFA deficiency, the lipid composition of BPM of the intestinal mucosal cells was little affected, suggesting
a preferential uptake of 20∶4n−6 and (or) precursor mobilized from other tissues. However, an effect of dietary treatment
on the function of membrane-associated proteins cannot be ruled out. 相似文献
19.
The effect of dietary zinc deficiency in the rat on the lipid composition of the erythrocyte membrane was determined. Weanling
male Wistar rats were fed an egg whitebased diet containing <1.0 mg Zn/kg dietad libitum. Control rats were either pair-fed orad libitum-fed the basal diet suppelemented with 100 mg Zn/kg diet. A zinc refed group was fed the −Zn diet until day 18 and then pairfed
the +Zn diet until day 21. The voluntary feed restriction associated with dietary zinc deficiency resulted in erythrocyte
membranes that had depressed phospholipid/protein and elevated cholesterol/phospholipid ratios. Similarly, all feed restricted
groups had elevated 22-carbon n−3 polyunsaturated fatty acid (PUFA) and depressed 22-carbon n−6 PUFA concentrations in alkenylacyl
and diacyl glycerophosphoethanolamine, phosphatidylserine and phosphatidylcholine; they also had depressed 24∶2n−6 levels
in sphingomyelin. The relative concentrations of phospholipids in the membrane was similar between −Zn and +Zn (ad libitum) groups; however, the −Zn group had significantly less phosphatidylserine relative to +Zn (pair-fed) controls. 相似文献
20.
Studies are reported on the composition of the lipids of human liver and hepatoma tissues from male adults. Liver tissues
were obtained from individuals who died from causes other than liver disease or cancer. The hepatoma tissues were obtained
from individuals shortly after they succumbed to cancer. The total lipid of each tissue was fractionated quantitatively by
silicic acid column chromatography into neutral lipid, glycolipid, and phospholipid fractions. These fractions were analyzed
by thin layer chromatography and converted to methyl esters for analysis of their constituent fatty acids by gas liquid chromatography.
In comparison to liver tissue, the total amount of lipid in the hepatoma tissues was generally higher and more variable; the
lipid of one hepatoma was ca. 92% of the dry wt of the tissue. The greater lipid content of the hepatoma tissues was due to
the high percentage of neutral lipid. Except for one specimen, there was ca. the same amount of glycolipid in the hepatoma
as in the liver tissues, but the composition of the glycolipid fraction of the hepatoma lipid differed considerably, particularly
in the ganglioside fraction. The phospholipid fraction of hepatoma lipid was much lower than that of liver but exhibited only
quantitative differences in composition. No glyceryl ether diesters and only traces of plasmalogens of phosphatidyl choline
or phosphatidyl ethanolamine were detected in the liver and hepatoma lipids. The levels of monoenoic acids were higher and
those of linoleic and polyunsaturated fatty acids lower in the hepatoma lipids. Positional isomers of trienoic acids not normally
present in liver tissue were detected in hepatoma lipids. The abnormalities observed in lipid composition indicated interferences
in the regulatory processes of lipid metabolism in human hepatoma similar to those observed in animals. 相似文献