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1.
This study examined the effect on the plasma lipids and plasma phospholipid and cholesteryl ester fatty acids of changing
from a typical western diet to a very low fat (VLF) vegetarian diet containing one egg/day. The effect of the addition of
saturated, monounsaturated or polyunsaturated fat (PUFA) to the VLF diet was also examined. Three groups of 10 subjects (6
women, 4 men) were fed the VLF diet (10% energy as fat) for two weeks, and then in the next two weeks the dietary fat in each
group was increased by 10% energy/week using butter, olive oil or safflower oil. The fat replaced dietary carbohydrate. The
VLF diet reduced both the low density lipoprotein (LDL)-and high density lipoprotein (HDL)-cholesterol levels; addition of
the monounsaturated fats and PUFA increased the HDL-cholesterol levels, whereas butter increased the cholesterol levels in
both the LDL- and HDL-fractions. The VLF diet led to significant reductions in the proportion of linoleic acid (18∶2ω6) and
eicosapentaenoic acid (20∶5ω3) and to increases in palmitoleic (16∶1), eicosatrienoic (20∶3ω6) and arachidonic acids (20∶4ω6)
in both phospholipids and cholesteryl esters. Addition of butter reversed the changes seen on the VLF diet, with the exception
of 16∶1, which remained elevated. Addition of olive oil resulted in a significant rise in the proportion of 18∶1 and significant
decreases in all ω3 PUFA except 22∶6 compared with the usual diet. The addition of safflower oil resulted in significant increases
in 18∶2 and 20∶4ω6 and significant decreases in 18∶1, 20∶5ω3 and 22∶5ω3. These results indicate that the reduction of saturated
fat content of the diet (<6% dietary energy), either by reducing the total fat content of the diet or by exchanging saturated
fat with unsaturated fat, reduced the total plasma cholesterol levels by approximately 12% in normocholesterolemic subjects.
Although the VLF vegetarian diet reduced both LDL- and HDL-cholesterol levels, the long-term effects of VLF diets are unlikely
to be deteterious since populations which habitually consume these diets have low rates of coronary heart disease. The addition
of safflower oil or olive oil to a VLF diet produced favorable changes in the lipoprotein lipid profile compared with the
addition of butter. The VLF diets and diets rich in butter, olive oil or safflower oil had different effects on the 20 carbon
eicosanoid precursor fatty acids in the plasma. This suggests that advice on plasma lipid lowering should also take into account
the effect of the diet on the fatty acid profile of the plasma lipids. 相似文献
2.
Rats were fed diets high in either saturated fat (beef tallow) or α-linolenic acid (linseed oil) or eicosapentaenoic and docosahexaenoic
acids (fish oil) with or without 2% cholesterol supplementation. Consumption of linseed oil and fish oil diets for 28 days
lowered arachidonic acid content of plasma, liver and heart phospholipids. Addition of 2% cholesterol to diets containing
beef tallow or linseed oil lowered 20∶4ω6 levels but failed to reduce 20∶4ω6 levels when fed in combination with fish oil.
Feeding ω3 fatty acids lowered plasma cholesterol levels. Addition of 2% cholesterol to the beef tallow or linseed oil diet
increased plasma cholesterol concentrations but not when fish oil was fed. Feeding the fish oil diet reduced the cholesterol
content of liver, whereas feeding the linseed oil diet did not. Dietary cholesterol supplementation elevated the cholesterol
concentration in liver in the order: linseed oil > beef tallow > fish oil (8.6-, 5.5-, 2.6-fold, respectively). Feeding fish
oil and cholesterol apparently reduced 20∶4ω6 levels in plasma and tissue lipids. Fish oil accentuates the 20∶4ω6 lowering
effect of dietary cholesterol and appears to prevent accumulation of cholesterol in plasma and tissue lipids under a high
dietary load of cholesterol. 相似文献
3.
To test the possibility that dietary palmitic acid (16∶0) may be lithogenic, different fats were blended to exchange 18∶1
in olive oil with either 16∶0 in palm stearin, 12∶0+14∶0 in coconut oil, or 14∶0+16∶0 in butterfat. Dietary 18∶2 was held
constant at 1.2% energy (en) (with extra safflower oil as needed) in these four purified diets containing low fat (11% of
total energy) and 0.4% cholesterol. A fifth, high-fat diet provided 40% of the total energy as the 16∶0-rich blend. All hamsters
fed the low-fat, 16∶0-rich blend for six weeks developed cholesterol gallstones (8/8). Although the gallstone incidence was
lower for the 12∶0+14∶0-rich diet (5/8), the severity of stone formation in affected hamsters was equal to that in the low-fat,
16∶0-rich group. Mucin accumulation in gallbladder bile was often associated with cholesterol gallstones in diets containing
16∶0, but was minimal in 18∶1-rich and 12∶0+14∶0-rich groups. Neither the lithogenic index (all>1.0), plasma lipids, nor liver
cholesterol was a selective predictor of stone formation. The high-fat, 16∶0-rich diet actually decreased cholesterol stone
incidence (3/8) and severity, but yielded a high incidence of pigment stones (5/8). Thus, saturated fat and 16∶0per se were not responsible for the exaggerated lithogenesis. Because the antilithogenic 18∶1-rich diet also normalized the 18∶2
intake (1.2% en) relative to previous butter diets (0.3% en), the potential importance of essential fatty acids (EFA) deficiency
in the model was tested in a second study by feeding graded amounts of 18∶2 (0.3, 0.6, 0.9, and 1.2% en) as safflower oil
in four low-fat, butter-rich diets (11% en as fat) without alleviating gallstone incidence or severity. These studies indicate
that substitution of 18∶1 for saturated fatty acids in low-fat diets reduces gallstone formation without affecting the lithogenic
index. Furthermore, intake of 18∶2 at or below the EFA requirement does not appear to be a major factor in this model. 相似文献
4.
Male Sprague-Dawley weanling rats were fed isocaloric diets consisting of 10% (by wt) fat. The six groups differed in the
ratio of corn oil and butter fat present in the diets such that: 10C, 10% corn oil (C); 8C2B, 8% C/2% butter fat (B); 6C4B,
6% C/4% B; 4C6B, 4% C/6% B; 2C8B, 2% C/8% B; and 10B, 10% B. Liver plasma membranes were analyzed for fatty acid composition
and cholesterol/phospholipid molar ratio. The 18∶2n−6 content was constant in the 10C and 8C2B diets and then decreased linearly
through the 2C8B diet. The 20∶4n−6 and 18∶1n−9 contents were constant except in the 10B diet, in which a significant decrease
and increase, respectively, were observed. The cholesterol/phospholipid molar ratio increased between the 10C and 6C4B diets
and subsequently (4C6B and 10B diets) remained constant. This data indicates that changes in n−6 fatty acid content in the
liver plasma membrane are directly related to dietary intake only for 18∶2n−6. Arachidonic acid content in the membrane is
maintained at a constant level until the linoleic acid content of the diet is reduced to 0.5% of calories. It also indicates
that the cholesterol content of the membrane becomes saturated and does not increase with increasing concentrations of saturated
fat in the diet.
Presented in part at the FASEB Meeting, Washington, D.C., April, 1987. 相似文献
5.
Weanling male Wistar rats were fed for five weeks on standard rat chow (23 g fat/kg diet) or one of four synthetic diets with
butterfat, coconut oil, corn oil, or fish oil as the main lipid source (100 g fat/kg diet). In all diets, 10% of the fat was
provided as corn oil to prevent essential fatty acid deficiency. Significant differences were observed in the saturated, monounsaturated,
and polyunsaturated fatty acid composition, and in the ratio of cholesterol to phospholipid, in the hepatocyte membranes.
The fluidity of hepatocyte plasma membranes was assessed using the fluorescence recovery after photobleaching technique and
steady-state fluorescence anisotropy of diphenylhexatriene. No significant differences were found in the fluidity of plasma
membranes between animals on the different fat diets, despite diet-induced changes in their fatty acid composition. However,
the proportion of lipid free to diffuse in the plasma membrane varied with diet, being significantly greater (P<0.05) in animals fed chow (63.7%), coconut oil (61.5%), and butterfat (57.6%) diets than in those fed the corn oil (47.3%)
diet. Animals fed fish oil showed an intermediate (50.0%) proportion of lipid free to diffuse. The data support the hypothesis
that dietary lipids can change both the chemical composition and lateral organization (lipid domain structure) of rat hepatocyte
plasma membranes. 相似文献
6.
Anne Javouhey-Donzel Lucien Guenot Véronique Maupoil Luc Rochette Gérard Rocquelin 《Lipids》1993,28(7):651-655
Three groups of sixteen male rats each were fed semipurified diets containing 15% by weight of lipid for a period of 4 wk.
The diets contained the same amount of polyunsaturated fatty acids (PUFA) (20% of total fatty acids) and saturated fatty acids
(19% of total fatty acids). Dietary PUFA were represented exclusively by linoleic acid (18∶2 diet), or 10% linoleic acid and
10% linolenic acid (18∶3 diet), or 10% linoleic acid and 10% long-chain n−3 fatty acids (LCn−3 diet). The overall amount of
vitamin E was similar in the three diets,i.e, 140, 133 and 129 mg/kg diet, respectively. Following appropriate extraction, tocopherol levels in heart, liver, brain, adipose
tissue (AT) and plasma were measured by high-performance liquid chromatography. The level of vitamin E in the heart decreased
with n−3 PUFA diets, most markedly with LCn−3 PUFA. Liver and AT vitamin E contents also decreased with n−3 PUFA diets when
expressed as μg/mg total lipids and μg/mg phospholipids, respectively. Total plasma vitamin E was lower in rats fed the LCn−3
diet, but there was no significant difference when expressed as μg/mg total lipids. Brain vitamin E was not affected by the
various diets.In vitro cardiac lipid peroxidation was quantified by the thiobarbituric acid reactive substances (TBARS) test. Heart homogenates
were incubated at 37°C for 15 and 30 min in both the absence (uninduced) or presence (induced) of a free radical generating
system (1 mM xanthine, 0.1 IU per mL xanthine oxidase, 0.2 mM/0.4 mM Fe/ethylenediaminetetraacetic acid). TBARS release was
time-independent but significantly higher when LCn−3 fatty acids were fed to rats in either the uninduced or induced system.
The study demonstrated that n−3 PUFA diets can influence vitamin E status of rats even in short-term experiments and can change
the susceptibility of the heart toin vitro lipid peroxidation. 相似文献
7.
Semipurified diets containing different lipids were fed to rat dams during lactation and subsequently to their pups for 33
weeks post-weaning. Some rats within each group were exposed to oxygen at hyperbaric pressure (OHP). Lipid peroxide levels
were lower in lungs of rats fed 7% hydrogenated coconut oil or 10% butter as compared with their controls, fed 7% corn oil
or 10% safflower oil, respectively. Exposure to OHP increased lung peroxide levels. This increase varied with the type of
fat in the diet. Studies of the fatty acid composition indicate that lipid peroxide levels generally increased with an increase
in the levels of 18∶2 in lung total lipids. The results suggest that the type of dietary lipid may alter the susceptibility
of the animal to pulmonary oxygen toxicity. 相似文献
8.
P. Wells L. Aftergood L. Parkin R. B. Alfin-Slater 《Journal of the American Oil Chemists' Society》1975,52(5):139-143
This study was designed to study the possible interrelationships between Torula yeast, vitamin E, and the dietary fat source on aflatoxin-induced tumors. Rats were fed Torula yeast-containing basal diets which included 1.7 ppm aflatoxin B1 with either lard, corn oil or no fat, and with or without vitamin E supplements for 3 months. Thereafter, the respective diets without aflatoxin were fed for ca. 9 months. Animals receiving the vitamin E-deficient diets had a high mortality. Although the vitamin E-deficient, aflatoxin-treated rats had lower wt gains than did the vitamin E-deficient controls, they lived twice as long. In addition, regardless of the dietary fat source, the kidneys and adrenals of these vitamin E-deficient, aflatoxin-supplemented rats were found to be significantly heavier than the controls, and plasma cholesterol levels were elevated. Increased amounts of liver lipid were observed in response to aflatoxin in both corn oil-fed and fat-deficient rats. No such differences were observed in the responses of the vitamin E-supplemented groups to aflatoxin. On the corn oil diet, aflatoxin administration resulted in an increased deposition of polyunsaturated fatty acids in cholesteryl ester and phospholipid fractions in livers of vitamin E-deficient rats and the phospholipid fraction of vitamin E-sufficient rats. The vitamin E-deficient rats exhibited necrosis of the liver, which was alleviated when aflatoxin was included in the diet, and calcification of the kidneys, which was potentiated by the dietary aflatoxin. No tumors were observed in these animals. In animals maintained on vitamin E-sufficient diets for 1 year, growth was depressed as a result of aflatoxin administration with the greatest depression occurring in the group fed corn oil. Spleen wt were decreased in all groups given aflatoxin. However, there were no changes in either plasma or liver cholesterol or total liver lipids which could be attributed to aflatoxin administration. When aflatoxin was fed with lard, the cholesteryl ester, triglyceride, and free fatty acid fractions of plasma had decreased amounts of the C20:4 acid. In the cholesteryl ester fraction only, this change was accompanied by increased levels of C16:0, C18:0, and C18:1 acids. In the liver phospholipids, there were increased levels of mono- and polyunsaturated fatty acids and decreases in the saturated fatty acids. All of the animals receiving aflatoxin exhibited severe necrosis and tumor formation in the kidneys; the animals fed lard had the highest level of involvement and those in the fat-free group the least. Liver pathology was the least marked among the rats fed the fat-free diet. Since aflatoxin-induced tumors are rich in lipids, the fat-free diet may be protective to the animal. 相似文献
9.
Kerin O'Dea Merryn Steel Joan Naughton Andrew Sinclair Grant Hopkins James Angus Guo-Wei He Margaret Niall T. J. Martin 《Lipids》1988,23(3):234-241
Rats were fed diets containing 10%, 30% or 50% energy as fat derived predominantly from butter or lard. The protein content
of the diets was maintained at 20%. After three weeks on the diets, the rats were killed and the following parameters measured:
prostacyclin production in vitro from abdominal aorta and mesenteric artery; platelet aggregation to ADP and thrombin; fatty
acid composition of the phospholipids in plasma, thoracic aorta and liver; smooth muscle reactivity and release of endothelial
derived relaxing factor (EDRF) from aortic endothelium stimulated by acetylcholine. There was no significant effect of increasing
fat content of the diets (neither lard nor butter) on platelet aggregation. In contrast, prostacyclin production in both the
mesenteric artery and the abdominal aorta fell in a concentration-dependent manner in the butter-supplemented rats. However,
no effect on prostacyclin production was detected in arteries from the lard-supplemented animals. The effects of the diets
on prostacyclin (PGI2) production correlated very well with the changes in plasma, aortic and liver phospholipid arachidonic acid (AA) and eicosapentaenoic
acid (EPA) contents. AA decreased in a concentration-dependent manner in the rats fed the butter-enriched diets but did not
change in those fed the lard-enriched diets, whereas EPA rose in a concentration-dependent manner in the butter-fed rats and
was unchanged in the lard-fed animals. The clear-cut effects of the butter-enriched diets on aortic phospholipid fatty acid
composition and aortic PGI2 production were accompanied by a significant reduction in smooth muscle relaxation to EDRF. These results indicate that in
the rat, enrichment of the diet with butter can reduce the concentration of AA and increase that of EPA in plasma and tissue
phospholipids with a parallel reduction in arterial PGI2 production and EDRF. 相似文献
10.
Hepatocyte plasma membranes were isolated from the livers of mice fed either a low fat diet or high fat diets containing polyunsaturated
or saturated fat. The combined rate and isopycnic ultracentrifugation technique which was used produced highly purified hepatocyte
plasma membrane fractions. The efficacy of the procedure was checked by electron microscopy and the assay of marker enzymes
for the different subcellular organelles. Mice were maintained on a low fat diet until 60–70 days of age, when they were fed
high fat diets containing polyunsaturated or saturated fat. The hepatocyte plasma membrane lipids of mice fed the polyunsaturated
fat diet for 4 wk contained increased proportions of the major dietary unsaturated fatty acid, linoleic acid, and increased
proportions of arachidonic acid. The proportion of linoleic and arachidonic acids decreased with continued feeding of the
polyunsaturated fat diet. The hepatocyte plasma membrane lipids of mice fed the saturated fat diet contained increased proportions
of oleic acid. 相似文献
11.
Male weanling rats were fed semi-synthetic diets high in saturated fat (beef tallow) vs high in linoleic acid (safflower oil)
with or without high levels of α-linolenic acid (linseed oil) for a period of 28 days. The effect of feeding these diets on
cholesterol content and fatty acid composition of serum and liver lipids was examined. Feeding linseed oil with beef tallow
or safflower oil had no significant effect on serum levels of cholesterol. Serum cholesterol concentration was higher in animals
fed the safflower oil diet than in animals fed the beef tallow diet without linseed oil. Feeding linseed oil lowered the cholesterol
content in liver tissue for all dietary treatments tested. Consumption of linseed oil reduced the arachidonic acid content
with concomitant increase in linoleic acid in serum and liver lipid fractions only when fed in combination with beef tallow,
but not when fed with safflower oil. Similarly, ω3 fatty acids (18∶3ω3, 20∶5ω3, 22∶5ω3, 22∶6ω3) replaced ω6 fatty acids (20∶4ω6,
22∶4ω6) in serum and liver lipid fractions to a greater extent when linseed oil was fed with beef tallow than with safflower
oil. The results suggest that the dietary ratio of linoleic acid to saturated fatty acids or of 18∶3ω3 to 18∶2ω6 may be important
to determine the cholesterol and arachidonic acid lowering effect of dietary α-linolenic acid. 相似文献
12.
Bertram I. Cohen Erwin H. Mosbach Nariman Ayyad Shigeo Miki Charles K. McSherry 《Lipids》1992,27(7):526-532
We tested two hypotheses, i) whether the type and the amount of fat in the diet will affect the formation of cholesterol gallstones
in the hamsters, and ii) whether palmitic acid, a major fatty acid component of butterfat, can act as a potentiator of cholesterol
cholelithiasis in the hamster. Young, male golden Syrian hamsters (Sasco) were fed a semipurified diet containing casein,
corn starch, cellulose and cholesterol (0.3%) to which various types and amounts of fat (butterfat, olive oil, menhaden oil,
corn oil) were added. All diets contained 2% corn oil to supply essential fatty acids to the growing hamsters. No deaths or
illness occurred during the experiment. Animals fed the semipurified diet plus 4% butterfat (group 1) had a gallstone incidence
of 63%. Replacement of butterfat with either olive oil, corn oil or menhaden oil prevented the formation of cholesterol gallstones
entirely (groups 2–4). When total butterfat was increased from 4% to 8% (group 8), the incidence of cholesterol gallstones
increased to 80%. Substitution of 4% olive oil (group 5), corn oil (group 6), or menhaden oil (group 7) for the additional
4% butterfat significantly reduced gallstones to 35%, 45% and 30%, respectively. The replacement of 4% butterfat with 1.2%
palmitic acid gave the highest incidence of cholesterol gallstones (95%). These results suggest that butterfat (and one of
its components, palmitic acid) intensifies gallstone formation in this model whereas mono- and polyunsaturated fats act as
inhibitors of cholesterol cholelithiasis. A fatty acid, possibly palmitic acid, appears to act as lithogen in our model. 相似文献
13.
M. Kruger C. M. Smuts A. J. S. Benadé J. E. Fincham C. J. Lombard E. A. Albertse K. J. van der Merwe 《Lipids》1992,27(10):733-739
The effects of the degree of unsaturation and of the amount of dietary fat on low density lipoprotein (LDL) concentration
and composition were determined in vervet monkeys. Diets with fat contents of 41, 31 and 18% energy, each with a low and a
high polyunsaturated to saturated fatty acid ratio (P/S; 0.27–0.38 and 1.13–1.47) were fed to six female vervet monkeys for
two months. Another six females were given a low fat, high P/S diet for the same period of time, to serve as a reference.
The cholesterol contents of the diets were low (21–33 mg per day) and relatively constant. LDL cholesterol concentrations
decreased significantly (P≤0.01) when the dietary fat content decreased from 31 to 18% of energy. The dietary P/S ratio only affected LDL cholesterol
concentrations during moderate (31% of energy) fat intake, where LDL cholesterol increased (P≤0.01) with a decrease in dietary P/S. Substantial individual variations were observed in LDL cholesterol concentration responses
to dietary fat changes. The changes in LDL cholesterol concentrations were the result of changes in the concentration of LDL
particles, as the molecular composition did not differ significantly between dietary periods. The high density lipoprotein
choelsterol and the plasma triacylglycerol concentrations were not influenced by the dietary fat changes. During the high
P/S diets, the percentage of 18∶2 (linoleic acid) increased (P≤0.01) and that of 18∶1 (oleic acid) decreased (P≤0.01) in LDL esterified cholesterol, as compared to the low P/S diets. In adipose tissue triacylglycerol the percentage of
18∶2 was three times higher (P≤0.01) during the high P/S diets than during the low P/S diets. A decrease in the amount of dietary fat (from 31 to 18% of
energy) was associated with an increase in the percentage of 18∶1 in LDL esterified cholesterol. 相似文献
14.
Comparative effects of feeding dietary linoleic (safflower oil) and α-linolenic (linseed oil) acids on the cholesterol content
and fatty acid composition of plasma, liver, heart and epididymal fat pads of rats were examined. Animals fed hydrogenated
beef tallow were used as isocaloric controls. Plasma cholesterol concentration was lower and the cholesterol level in liver
increased in animals fed the safflower oil diet. Feeding the linseed oil diet was more effective in lowering plasma cholesterol
content and did not result in cholesterol accumulation in the liver. The cholesterol concentration in heart and the epididymal
fat pad was not affected by the type of dietary fatty acid fed. Arachidonic acid content of plasma lipids was significantly
elevated in animals fed the safflower oil diet and remained unchanged by feeding the linseed oil diet, when compared with
the isocaloric control animals fed hydrogenated beef tallow. Arachidonic acid content of liver and heart lipids was lower
in animals fed diets containing safflower oil or linseed oil. Replacement of 50% of the safflower oil in the diet with linseed
oil increased α-linolenic, docosapentaenoic and docosahexaenoic acids in plasma, liver, heart and epididymal fat pad lipids.
These results suggest that dietary 18∶2ω6 shifts cholesterol from plasma to liver pools followed by redistribution of 20∶4ω6
from tissue to plasma pools. This redistribution pattern was not apparent when 18∶3ω3 was included in the diet. 相似文献
15.
Interrelationship of stearic acid content and triacylglycerol composition of lard,beef tallow and cocoa butter in rats 总被引:4,自引:0,他引:4
We investigated modes whereby stearic acid (18∶0) exerts a neutral or cholesterol-lowering effect using dietary fats which
provided graded levels of 18∶0 and distinct triacylglycerol (TAG) profiles. Male Sprague-Dawley rats (150–175 g) were fed
diets containing 0.2% cholesterol and 16% fat from corn oil, or from 1% corn oil plus 15% lard (13.2% 18∶0), beef tallow (19.2%
18∶0) or cocoa butter (34.7% 18∶0) for 3 wk, and then killed in a fasted or fed state. Chylomicron (CM) fatty acid profiles
suggested reduced absorption of 18∶0 with greater 18∶0 intake. CM TAG profiles indicated a reduction or loss of two TAG species
compared to the TAG profiles of the stearate-rich diets: 1-palmitoyl-2-oleoyl-3-stearoyl glycerol (POS) and 1,3-distearoyl-2-oleoyl
glycerol (SOS). Hepatic total cholesterol concentrations were 54–77% lower (P<0.01) in the cocoa butter-fed than the lard- and beef tallow-fed groups. The cocoa butter group showed a significantly lower
ratio of high-density lipoprotein esterified/free cholesterol than all other groups. Hepatic stearoyl-CoA and oleoyl-CoA concentrations,
the substrate and product for hepatic δ9 desaturase, were not significantly different for corn oil-fed and cocoa butter-fed
groups in spite of a large difference in 18∶0 intake. These data suggest that the neutral or cholesterol-lowering effect of
18∶0 is not due to hepatic conversion of stearic to oleic acid, and that POS and SOS are poorly absorbed from stearate-rich
dietary fats. 相似文献
16.
Two nutritional models, essential fatty acid (EFA) deficiency and the feeding of saturated vs unsaturated fats, were used
to determine the effects of dietary lipids on the fatty acid composition of rat lung and lavage. Semipurified diets containing
7% corn oil, 7% hydrogenated coconut oil (EFA-deficient), 10% butter or 10% safflower oil were fed to dams during lactation
and thereafter to their offspring for a total of 24 weeks. Lipids were extracted from the lung lavage and lung tissue and
their fatty acid composition was determined. The content of dipalmitoylphosphatidylcholine (DPPC), the main surfactant in
the lungs, was also determined. The results show that the levels of DPPC in the lungs of rats fed 10% butter decreased although
the decrease in the EFA-deficient rats was greater. Comparing rats fed butter with those fed corn oil, there were also modifications
in the fatty acid composition of the total lipids and phospholipids of lung tissue and lavage as well as in phosphatidylcholine,
phosphatidylethanolamine and phosphatidylinositol +phosphatidylserine fractions isolated from the lung tissue. The changes
in fatty acid composition were somewhat fewer in rats fed butter then in those fed an EFA-deficient diet. The results suggest
that a marginal EFA deficiency produced in rats by long-term feeding of 10% butter may account for the reduction in DPPC levels
and in the changes in fatty acid composition in the lung tissue and lavage. 相似文献
17.
18.
The effect of diets high (15%) in saturated (beef tallow) or polyunsaturated (corn or cottonseed oil) fatty acids on the fatty
acid composition of sphingomyelin from canine erythrocytes and platelets and sphingomyelin and neutral glycosphingolipids
of swine erythrocytes was determined. Sphingolipids of platelets and erythrocytes from animals fed high levels of corn or
cottonseed oil exhibited a dramatic alteration in their fatty acid composition, most notable of which was a 50% reduction
in nervonic acid (24∶1ω9) as compared to levels observed in control or tallow fed animals. This decrease was compensated for
by a quantitatively similar increase in a C24 dienoic acid. The long chain dienoic acid was isolated by silver nitrate thin layer chromatography and determined by analysis
of its oxidation products to be Δ15, 18-tetracosadienoic acid (24∶2ω6). When the animals were fed the diets high in polyunsaturates,
the 24∶2ω6 represented 13, 20, and 9% of the sphingomyelin fatty acids from canine erythrocytes, platelets, and swine erythrocytes,
respectively, and 5% of the neutral glycosphingolipid fatty acids of swine erythrocytes. In contrast, the 24∶2ω6 represented
less than 4% of the total cellular sphingolipid fatty acids in animals fed the control or high beef tallow diets. The 24∶1ω9
in the sphingolipids of the animals fed the polyunsaturated diet was roughly equal to that of 24∶2ω6, whereas in the sphingolipids
of animals fed the control or saturated fat (beef tallow) diet, the 24∶1ω9 was twice these values. Since sphingomyelin is
a membrane component, the increase in unsaturation (24∶2ω6) in its fatty acid moiety induced by dietary polyunsaturates may
affect membrane fluidity and may alter membrane properties.
Dr. Nelson’s current affiliation is with the Lipid Metabolism Branch, Division of Heart and Vascular Diseases, National Heart,
Lung, and Blood Institute. 相似文献
19.
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
20.
R. B. Alfin-Slater P. Wells L. Aftergood D. Melnick 《Journal of the American Oil Chemists' Society》1973,50(12):479-484
In a long-term multigeneration study, conducted in our laboratories for 32-years, with occasional longevity and histopathological
evaluations included, rats of our own inbred strain (originally of Wistar derivation) were fed semisynthetic diets comprising
whole wheat, skim milk powder, and fat in the form of margarine products. The total source of tocopherols was the dietary
fat itself. Saturated fatty acid content (S) remained relatively constant at about 20% of the fat and total tocopherol level
also remained constant at about 0.12% of the fat. Polyunsaturated fatty acid (P) content, however, progressively increased
almost fourfold, from 7.5% to 28.5% and alphatocopherol levels decreased to one-half level, from 0.033% to 0.016% of the fat.
Hence, the ratio of polyunsaturated fatty acids to alpha-tocopherol content changed markedly from 227∶1 to 1780∶1, with other
factors (relative to fat composition) held constant during the 32-year period of feedings and observations. Fat level in the
diet increased over the years from 9.2% to 16.0% or from about 21% to about 33% of the caloric intake. Thus, quality and quantity
of the fat in the diet progressively changed, and the impact of these changes was evaluated by comparing biological performances
of the successive generations. Growth and reproduction and lactation performances were noted to be regularly satisfactory
and comparable from generation to generation throughout the experimental period. Longevity studies conducted on arbitrarily
selected generations also provided data showing no deleterious effects associated with a dietary change. Histopathological
examinations of tissue revealed minimal myocarditis and no malignant tumors which could be attributed to a dietary factor.
No vitamin E deficiencies were observed. Even the in vitro peroxide hemolysis values for the red blood cells of the animals,
fed the diets containing the higher levels of polyunsaturated fatty acids, were low, indicating that the dietary fats provided
sufficient absorbable tocopherol to protect the potentially oxidizable unsaturated fatty acids in the erythrocyte membrane.
Biochemical data reflected responses to aging and not to any specific diet fed. It is concluded that a diet providing as much
as 33% of the calories as a fat, the latter containing up to 28.5% polyunsaturated fatty acids, substantially of the essential
fatty acid type, with a P/S ratio of up to 1.6∶1 and a polyunsaturated fatty acid to alphatocopherol ratio as high as 1780∶1]
produces no undesirable effects in the rat.
Presented in part at a symposium entitled “Long Term Nutritional Effects of Dietary Fats” at the International Society for
Fat Research World Congress, September 30, 1970, Chicago, Illinois. 相似文献