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1.
M. Keelan K. Doring M. Tavernini E. Wierzbicki M. T. Clandinin A. B. R. Thomson 《Lipids》1994,29(12):851-858
Diabetes-associated changes in intestinal uptake of nutrients are modified by isocaloric variations in the type of dietary
lipids, and are associated with alterations in the phospholipid and fatty acyl content of the intestinal brush border membrane.
The present study was designed to test the hypothesis that diet- and diabetes-associated changes in enterocyte microsomal
membrane phospholipids are due to variations in the activity of two phospholipid metabolizing enzymes, 1,2-diacylglycerol:
CDP choline cholinephosphotransferase (CPT) and phosphatidylethanolamine methyltransferase (PEMT). Adult female Wistar rats
were fed one of four semisynthetic diets—beef tallow low in cholesterol (BT), beef tallow high in cholesterol (BTC), fish
oil low in cholesterol (FO) or fish oil high in cholesterol. In half of the animals, diabetes mellitus was produced by injection
of streptozotocin. Jejunal and ileal enterocyte microsomes (EMM) were isolated and analyzed for cholesterol and phospholipids,
as well as for CPT and PEMT activities. In control animals, feeding FO reduced EMM total phospholipids including phosphatidylcholine
(PC), phosphatidylethanolamine (PE) and phosphatidylinositol. Feeding FO resulted in a greater than 95% reduction in the activity
of CPT. Diabetes was associated with increased jejunal EMM total phospholipids including sphingomyelin (SM) and PE, without
associated changes in CPT or PEMT. Dietary cholesterol supplementation did not effect EMM total cholesterol or phospholipid
composition in control rats fed BT or FO, but was associated with an increase in EMM cholesterol in diabetic rats fed BT or
FO. A decrease in total phospho-lipids due to a decline in SM, PC and PE in diabetic rats fed FO was not associated with changes
in the activities of CPT or PEMT in EMM. Thus (i) enterocyte microsomal membrane cholesterol and phospholipid contents are
influenced by diabetes, dietary cholesterol and the type of fatty acid in the diet, and (ii) changes in phospholipid composition
are not fully explained by alterations in the activities of CPT and PEMT. 相似文献
2.
Effects of diets high in saturated fat and cholesterol on the lipid composition of canine platelets 总被引:1,自引:0,他引:1
The phospholipid composition of platelets from dogs on various experimental diets was determined. Thyroidectomized foxhounds
were fed a control diet or the control diet supplemented with (1) beef tallow, (2) beef tallow and cholesterol, or (3) beef
tallow, cholesterol, and safflower oil for 23 weeks prior to isolation of platelets. Platelets from animals fed the control
diet contained 36.7% phosphatidylcholine (PC), 22.8% phosphatidylethanolamine (PE), 18.4% sphingomyelin (Sph), 11.8% phosphatidylserine
(PS), 6.3% phosphatidylinositol (PI), and 2.2% lysophosphatidylcholine. The PE was 77.6% in the plasmalogen form. No highly
significant changes in the phospholipid class composition resulted from the experimental diets. Cholesterol supplementation
of the diets, however, caused consistent alterations in the fatty acid compositions of the platelet phospholipids including
increases in the percentages of 18∶1ω9 (oleic acid), 18∶2ω6 (linoleic acid), and 20∶3ω6 (homo-gamma linolenic acid) and a
decrease in the percentage of 20∶4ω6 (arachidonic acid). Addition of safflower oil to the tallow-cholesterol diet partially
reversed these effects. These cholesterol-induced alterations in fatty acid composition could be due to exchange with plasma
lipids, de novo synthesis, or altered platelet metabolism. The mechanism remains to be determined.
Der. Nelson’s current affiliation is the Lipid Metabolism Branch, Division of Heart and Vascular Diseases, National Heart,
Lung, and Blood Institute. 相似文献
3.
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
4.
We compared the effects of three different high-lipid diets on plasma lipoproteins and phospholipids in mink (Mustela vison). The 18 mink studied were fed one of the three diets during a 25-d period in a parallel group design. The compared diets
had 0,17, and 67% extracted lipids from natural gas-utilizing bacteria (LNGB), which were rich in PE. The group with 0% LNGB
was fed a diet for which the lipid content was 100% soybean oil. The total cholesterol, LDL cholesterol, and HDL cholesterol
of animals consuming a diet with 67% LNGB (67LNGB-diet), were significantly lowered by 35, 49, and 29%, respectively, and
unesterified cholesterol increased by 17% compared with the animals fed a diet of 100% lipids from soybean oil (SB-diet).
In addition, the ratio of LDL cholesterol to HDL cholesterol was 27% lower in mink fed the 67LNGB-diet than those fed the
SB-diet. When the mink were fed the 67LNGB-diet, plasma PC, total phospholipids, lysoPC, and PI were lowered significantly
compared with the mink fed a SB-diet. Plasma total cholesterol was correlated with total phospholipids as well as with PC
(R=0.8, P<0.001). A significantly higher fecal excretion of unesterified cholesterol, cholesteryl ester, PC, lysoPC, and PE was observed
in the 67LNGB-fed mink compared with the SB-fed mink. We conclude that phospholipids from the 67LNGB-diet decreased plasma
lipoprotein levels, the LDL/HDL cholesterol ratio, and plasma phospholipid levels, especially lysoPC and PC, compared with
the highly unsaturated soybean oil. Our findings indicate that the decrease of plasma cholesterol is mainly caused by a specific
mixture of phospholipids containing a high level of PE, and not by the dietary FA composition. The lack of significant differences
in the level of plasma PE due to the diets indicates that most of the PE from LNGB has been converted to PC in the liver.
Thus, plasma cholesterol may at least be partly regulated by phospholipid methylation from PE to PC in the liver. 相似文献
5.
Effects of ethanol diets on cholesterol content and phospholipid acyl composition of rat hepatocytes
Chronic treatment of adult male rats with ethanol liquid diets resulted in alterations in phospholipid and cholesterol contents
as well as the acyl composition of phosphatidylethanolamine (PE), phosphatidylinositol (PI)-phosphatidylserine (PS) mixture,
and phosphatidylcholine (PC) of isolated hepatocytes. The influence of ethanol on these lipids was largely dependent on the
proportion of dietary fat. Phospholipid and total cholesterol contents were elevated 23 and 27%, respectively, by ethanol
when offered in a low-fat diet (5% corn oil). Only the percentage of arachidonic acid from PI-PS was significantly reduced
in the low-fat ethanol group. Exposure to a high-fat (34% corn oil) diet in the presence of ethanol for 4–5 weeks resulted
in a significant decrease in arachidonate/linoleate ratios of hepatic PE, PS-PI and PC, while total phospholipid content remained
constant. In the high-fat, ethanol-treated group, hepatic cholesterol content was increased 2-fold. These results suggest
that the level of dietary fat plays an important role in determining the effects of chronic ethanol consumption on hepatic
cholesterol content and phospholipid acyl composition. 相似文献
6.
Locally and systemically active glucocorticosteroids modify intestinal absorption of lipids in rats 总被引:3,自引:0,他引:3
Orally administered systemically active steroids enhance the digestive and absorptive functions of the intestine, but their
effect on lipid uptake is unknown. The effect of the locally acting steroid budesonide on intestinal absorptive function also
is unknown. Accordingly, this study was undertaken to assess the influence of 4 wk of treatment of weaning male rats with
a daily oral gavage of budesonide (BUD), prednisone (PRED), or control vehicle on the jejunal and ileal uptake of fatty acids
and cholesterol. BUD enhanced jejunal uptake of oleic acid and ileal uptake of linoleic acid. PREF increased jejunal uptake
of cholesterol and ileal uptake of lauric, palmitic, linoleic, and linolenic acids. Higher doses of BUD (up to 1 mg/kg) given
to adult rats for 2 wk further increased the uptake of some lipids. The changes in the uptake of lipids were not due to variations
in the weight of the intestinal mucosa or in the animals’ food intake. Ileal ornithine decarboxylase mRNA expression was increased
with PRED, but there were no steroid-associated changes in the expression of the mRNA of the early response genes c-myc, c-jun,
or c-fos or of proglucagon, the liver fatty acid-binding protein (FABP), the ileal lipid-binding protein, tumor necrosis factor
α, interleukin 2 (IL-2), IL-6, or IL-10. In summary, treatment of weanling rats with BUD and DRED enhances the uptake of some lipids by a process that is independent of the effects of early response genes and genes encoding
cytokines, proglucagon, and FABP. 相似文献
7.
Cholesterol-lowering effects of guar gum: Changes in bile acid pools and intestinal reabsorption 总被引:1,自引:0,他引:1
Soluble fibers such as guar gum (GG) may exert cholesterol-lowering effects. It is generally accepted that bile acid (BA)
reabsorption in portal blood is reduced, thus limiting the capacity of BA to down-regulate liver cholesterol 7α-hydroxylase,
the rate-limiting enzyme of BA synthesis. In the present work, rats were adapted to fiber-free (FF) or 5% GG diets (supplemented
or not with 0.25% cholesterol), to investigate various aspects of enterohepatic BA cycling. GG in the diet at a level of 5%
elicited a significant lowering of plasma cholesterol during the absorptive period, in cholesterol-free (−13%) or 0.25% cholesterol
(−20%) diet conditions. In rats adapted to the GG diets, the small intestinal and cecal BA pools and the ileal vein-artery
difference for BA were markedly enhanced; reabsorption in the cecal vein was also enhanced in these rats. [14C]Taurocholate absorption, determined in perfused ileal segments, was not significantly different in rats adapted to the FF
or GG diet, suggesting that a greater flux of BA in the ileum might support a greater ileal BA reabsorption in rats adapted
to the GG diet. In contrast, capacities for [14C]cholate absorption from the cecum at pH 6.5 were higher in rats adapted to the GG diet than to the FF diet. Acidification
of the bulk medium in isolated cecum (from pH 7.1 down to pH 6.5 or 5.8) or addition of 100 mM volatile fatty acids was also
found to stimulate cecal [14C]cholate absorption. These factors could contribute to accelerated cecal BA absorption in rats fed the GG diet. The effects
of GG on steroid fecal excretion thus appear to accompany a greater intestinal BA absorption and portal flux to the liver.
These results suggest that some mechanisms invoked to explain cholesterol-lowering effect of fibers should be reconsidered. 相似文献
8.
David Kritchevskya Shirley A. Tepper Subramanian Satchithanandam Marie M. Cassidy George V. Vahouny 《Lipids》1988,23(4):318-321
Rats (6 per group) were fed semipurified diets containing either particulate fibers (alfalfa, 10%; cellulose, 10%; bran, 10%),
a soluble ionic fiber (pectin 5%), soluble, nonionic fibers (guar gum, 5%; Metamucil, 10%), a mixed fiber preparation (Fibyrax,
10%, or an insoluble, ionic bile acid-binding resin (cholestyramine, 2%). The control group was fed the unsupplemented diet.
The feeding period, during which diet and water were provided ad libitum, was 28 days.
Compared with the control group, serum total cholesterol levels were increased by more than 10% in rats fed alfalfa and decreased
by more than 10% in rats fed cellulose, guar gum, Fibyrax and cholestyramine. There were no significant differences in percentage
of plasma HDL cholesterol. Serum triglycerides were elevated in the groups fed alfalfa, pectin, guar gum or Fibyrax and reduced
in the group fed Metamucil. Plasma phospholipids were elevated in rats fed alfalfa or bran, unaffected in rats fed pectin
or Metamucil and reduced in the other groups. Liver total cholesterol was elevated in all groups but those fed wheat bran
and cholestyramine. The percentage of liver cholesterol present as ester was elevated in every group except that fed cholestyramine.
Liver triglycerides were reduced in rats fed guar gum or Metamucil and elevated in those fed alfalfa. Liver phospho-lipids
were lowered in the group fed cellulose.
Liver phospholipids were fractionated by thin layer chromatography to give phosphatidylcholine (PC), phosphatidylethanolamine
(PE), sphingomyelin (Sph), lysophosphatidylcholine (LPC) and phosphatidylinositol plus phosphatidylserine (PI+PS). PC was
elevated in all test groups (7–25%); PE levels ranged from 14% below to 0.3% above controls; Sph levels were sharply lower
(20–53%) in all groups. LPC and PI+PS levels were close to the control value in all test groups.
The results demonstrate that different dietary fibers can affect liver phospholipid composition. In view of the critical roles
of phospholipids in many biological reactions, it will be interesting to survey the influence of dietary fiber on phospholipid
spectra of other tissues.
Deceased. 相似文献
9.
10.
Omega-3 fatty acids influence the function of the intestinal brush border membrane. For example, the omega-3 fatty acid eicosapentaenoic
acid (20∶5ω3) has an antiabsorptive effect on jejunal uptake of glucose. This study was undertaken to determine whether the
effect of feeding α-linolenic acid (18∶3ω3) or EPA plus docosahexaenoic acid (22∶6ω3) on intestinal absorption of nutrients
was influenced by the major source of dietary lipid, hydrogenated beef tallow or safflower oil. Thein vitro intestinal uptake of glucose, fatty acids and cholesterol was examined in rats fed isocaloric diets for 2 weeks: beef tallow,
beef tallow + linolenic acid, beef tallow + eicosapentaenoic acid/docosahexaenoic acid, safflower oil, safflower oil + linolenic
acid, or safflower oil + eicosapentaenic acid/docosahexaenoic acid. Eicosapentaenoic acid/docosahexaenoic acid reduced jejunal
uptake of 10 and 20 mM glucose only when fed with beef tallow, and not when fed with safflower oil. Linolenic acid had no
effect on glucose uptake, regardless of whether it was fed with beef tallow or safflower oil. The jejunal uptake a long-chain
fatty acids (18∶0, 18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3 and 22∶6ω3) and cholesterol was lower in salfflower oil than with beef tallow.
When eicosapentaenoic acid/docosahexaenoic acid was given with beef tallow (but not with safflower oil), there was lower uptake
of 18∶0, 20∶5ω3 and cholesterol. The demonstration of the inhibitory effect of linolenic acid or eicosapentaenoic acid/docosahexaenoic
acid on cholesterol uptake required the feeding of a saturated fatty acid diet (beef tallow). These changes in uptake were
not explained by differences in the animals’ food intake, body weight gain or intestinal weight. Feeding safflower oil was
associated with an approximately 25% increase in the jejunal and ileal mucosal surface area, but this increase was prevented
by combining linolenic acid or eicosapentaenoic acid/docosahexaenoic acid with safflower oil. Different inhibitory patterns
were observed when mixtures of fatty acids were present together in the incubation medium, rather than in the diet: for example,
when 18∶0 was in the incubation medium with 20∶4ω6, the uptake of 20∶4ω6 was reduced, whereas the uptake was unaffected by
18∶2ω6 or 20∶5ω3. Thus, (1) the inhibitory effect of eicosapentaenoic acid/docosahexaenoic acid on jejunal uptake of glucose,
fatty acids and cholesterol was influenced by the major dietary lipid, saturated (beef tallow) or polyunsaturated fatty acid
(safflower oil); and (2) different omega-3 fatty acids (linolenic acid versus eicosapentaenoic acid/docosahexaenoic acid)
have a variable influence on the intestinal absorption of nutrients. 相似文献
11.
Severe iron deficiency affects lipid metabolism. To investigate whether moderate iron depletion also alters lipid variables—including
lipid levels in serum and liver, hepatic lipogenesis, and fatty acid composition indicative of an impaired desaturation—we
carried out experiments with rats fed 9, 13, and 18 mg iron/kg diet over a total of 5 wk. The study also included three pair-fed
control groups and an ad libitum control group, fed with 50 mg iron/kg diet. The iron-depleted rats were classified as iron-deficient on the basis of reduced
serum iron, hemoglobin concentration, and hematocrit. All moderately iron-deficient rats had significantly lower cholesterol
concentrations in liver and serum lipoproteins than their pair-fed controls. Rats with the lowest dietary iron supply had
higher concentrations of hepatic phosphatidylcholine (PC) and phosphatidylethanolamine (PE), lower activities of glucose-6-phosphate
dehydrogenase, malic enzyme and fatty acid synthase, and higher triacylglycerol concentrations in serum lipoproteins than
the corresponding pair-fed control rats. Moderate iron deficiency also depressed the serum phospholipid level. Moreover, several
consistent significant differences in fatty acid composition of hepatic PC and PE occurred within moderate iron deficiency,
which indicate impaired desaturation by Δ-9 and Δ-6 desaturases of saturated and essential fatty acids. We conclude that lipid
variables, including cholesterol in liver and serum lipoproteins as well as fatty acid desaturation, reflect the gradations
of iron status best and can be used as an indicator of the degree of moderate iron deficiency. 相似文献
12.
Dietary fat and abnormal production of various prostanoids have been linked to various disease states of the large bowel,
including cancer of the colon. Studies were conducted to determine the effect of dietary fat (beef tallow or corn oil) on
the lipid composition and prostanoid production of the murine colon.
Female C57BL/6J mice were fed high-fat (HF) diets (47% of calories as fat) or low-fat (LF) diets (10% of calories as fat).
After four wk of dietary treatment, the mucosa was scraped, and lipids were extracted from the mucosal and muscle layers.
The fat content of the diets did not significantly alter the amount of phospholipid (PL) or neutral lipid in the colonic tissue.
However, the HF affected the PL profile of the colonic mucosa. For example, the ratio of phosphatidylcholine (PC) to phosphatidylethanolamine
(PE) was significantly higher for both the HF groups compared with that of the two LF groups (0.76±0.15 and 0.80±0.13 vs 0.31±0.20
and 0.34±0.18). Production of 13,14-dihydro-15-keto-PGE2 (measured as bicyclic PGE2) and TXB2 (a stable metabolite of TXA2) and PGF1α (a stable metabolite of PGI2) was unaffected by the dietary treatments. The muscle had a different PL profile (PC:PE is 2.6±0.1) than the mucosa and contributed
a larger proportion of the prostanoids formed. This study demonstrates that the phospholipid polar head group composition
of normal colonic mucosa is altered by dietary fat, but the ability of the mucosa to synthesize metabolites of PGE2, TXA2 and PGI2 is not affected.
ARC Contribution No. 1504. 相似文献
13.
A line of mice was developed which exhibited spontaneous obesity when fed commercial laboratory ration low in fat content.
Obese mice were compared to a nonobese related line to determine whether energy source in the diet would affect onset of obesity.
Experimental diets-beef tallow (38% of calories as beef fat and 2% as corn oil), corn oil (40% corn oil) or low-fat (2% corn
oil)-were instituted ad libitum at the time of weaning. When the mice reached 6 months of age, lipogenesis was investigated
by injecting intravenously3H2O and glucose-U-14C.3H2O and glucose-U-14C incorporation into fatty acids of fed mice was greater for obese than for lean mice. Fatty acid synthesis was inhibited
by high-fat diets compared to low-fat diet in both lines. Of the 2 high-fat diets, the corn oil diet inhibited fatty acid
synthesis about twice as much as beef tallow diet. There was no line effect on tritium incorporation into cholesterol. Cholesterol
synthesis from glucose-U-14C was greater in obese than lean mice. Diets had no effect on tritium and glucose-U-14C incorporation into cholesterol. Fasting reduced fatty acid synthesis in all mice, but total body fatty acid synthesis was
not affected by lines or dietary treatment under fasted conditions. These data suggest that degree of lipogenesis, in part,
explains obesity. A failure of inhibition of lipogenesis or an enhanced efficiency in fat deposition by feeding beef tallow
compared to corn oil diet may explain the fact that lean mice fed the beef tallow diet tended to be more obese that lean mice
fed corn oil or low-fat diets. 相似文献
14.
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
15.
The effect of dietary restriction of n−3 fatty acids during development on brain phospholipid fatty acid composition and exploratory
behavior has been studied in male Sprague Dawley rats. Female rats were fed semipurified diets containing either 5.5% safflower
oil or 6% soybean oil for 6 wk prior to mating and throughout gestation and lactation. Control rats were maintained on laboratory
chow. The male pups were weaned to the diets of the dams except for one group which was switched from safflower to soybean
oil at weaning. Behavioral studies and brain phospholipid analyses were conducted at 16–18 wk of age. Rats fed safflower oil
showed significantly lower levels of 22∶6n−3 in phospholipids of synaptic membranes and myelin than rats fed soybean oil or
chow. The decrease in 22∶6n−3 was compensated for by an increase in 22∶5n−6, the total content of polyunsaturated fatty acids
remaining approximately constant. The brain phospholipid fatty acid composition of rats switched from safflower to soybean
oil at weaning was similar to that of rats fed soybean oil throughout the experiment. There was no difference in spontaneous
locomotor activity among the different dietary groups. However, rats raised on safflower oil displayed a significantly lower
exploratory activity (horizontal movements and rearings) in a novel environment than rats fed soybean oil or chow. In contrast
to the brain phospholipid fatty acid composition, there was no recovery of exploratory behavior in rats raised on safflower
oil and switched to soybean oil at weaning suggesting a specific requirement of n−3 fatty acids during development. 相似文献
16.
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
17.
The impact of a moderate Zn deficiency on growth and plasma and liver lipids was investigated in two 4-week experiments with
male weanling rats fed fat-enriched diets. Semisynthetic, approximately isocaloric diets containing 3% soybean oil were supplemented
with either 7 or 100 mg Zn/kg diet and with 22% beef tallow (BT) or sunflower oil (SF). In Experiment 1, which compared the
dietary fat level and the fat source in a factorial design of treatments, all diets were fed ad libitum to 6 × 8 animals,
whereas intake of the high-Zn BT and SF diets was restricted in Experiment 2 (5 × 6 rats) to the level of intake of the respective
low-Zn diets. The low-Zn SF diet consistently depressed food intake and final live weights of the animals to a greater extent
than the other low-Zn diets, while intake and growth were comparable among the animals fed the high-Zn diets. The marginal
Zn deficit per se did not alter plasma triglyceride and cholesterol concentrations nor hepatic concentrations of triglyceride,
cholesterol and phospholipids. The fatty acid pattern of liver phospholipids did not indicate that chain elongation and desaturation
of fatty acids was impaired by a lack of zinc. It was concluded that dietary energy and fat intake, and fat source have a
greater effect on plasma and liver lipids than a moderate Zn deficiency. Marginally Zn-deficient diets enriched with sunflower
oil as a major energy source cause a greater growth retardation than diets rich in carbohydrates or beef tallow. 相似文献
18.
Ethyl-14C-acetoacetate was used to trace oxidation and metabolism of acetoacetate when rats were fed a high fat diet (80% of total
calories from beef tallow or corn oil, carbohydrate free), a high carbohydrate diet (2% corn oil) or a high carbohydrate diet
with restriction of calories to one half of ad lib. consumption for two weeks. The rate of expiration of14CO2 in all groups of animals did not differ significantly and was not related to plasma concentration of acetoacetate. The high
fat diets slightly enhanced the oxidation of acetoacetate to14CO2 over a 3 hr period compared to other diets. Incorporation of acetoacetate into fatty acids did not differ significantly among
groups. Rats fed the high carbohydrate diet ad lib. incorporated into liver cholesterol more acetoacetate than did any other
group, but dietary unsaturated fat resulted in greater incorporation of acetoacetate into cholesterol than saturated fat.
High calorie and high beef tallow groups were ketonemic but the low concentration of plasma acetoacetate in rats fed a high
corn oil diet indicates that unsaturated fatty acids are not ketogenic. The data show that utilization of acetoacetate is
not significantly reduced in a ketonemic condition and support the premise that overproduction of ketone bodies is the cause
of ketonemia. Rats appeared to be normal during the two-week period when no carbohydrate was included in the diet.
Presented at the AOCS Meeting, Chicago, October, 1967. 相似文献
19.
The purpose of this study was (i) to determine whether dietary fat-induced differences in neural and retinal membranes occur
when dietary fat treatment is implemented in aged animals and (ii) to characterize the effect of long-term differences in
dietary fat on neural and retinal membrane composition. For the first objective, young (six-week-old) and old (95-week-old)
mice were randomly assigned to beef tallow (TAL) or soybean oil (SBO) diets for eight weeks. For the second objective, young
(four-week-old) mice consumed either TAL or SBO diets for 99 weeks. Young and old mice challenged with a change in dietary
fat for an eight-week period showed both diet and age effects on neural and retinal phospholipid fatty acid composition (P<0.05). In addition, significant diet by age interactions were evident. In mice that consumed TAL and SBO diets throughout
their life, only retinal phosphatidylethanolamine (PE) 18∶2n−6 and neural phosphatidylserine 22∶5n−6, PE 18∶2n−6 and phosphatidylcholine
18∶2n−6 differed between dietary treatments (P<0.05). Neither the unsaturation index nor the n−6/n−3 ratio was affected by diet. Neural and retinal phospholipid fatty acid
composition were responsive to changes in dietary fat even when the treatment was implemented beyond developmental or post-weanling
stages. In contrast, when mice consumed TAL or SBO diets throughout their life, fewer differences in phospholipid fatty acid
composition were detected, suggesting that the effect of the dietary treatment was mitigated by aging. 相似文献
20.
Jeannie Leonardi Elise Termine Florence Morand Raymond Lafont Henri Portugal Huguette Lafont Gilles Nalbone 《Lipids》1987,22(7):517-522
Rats were fed lard-enriched (17%) or corn oil-enriched (17%) diets and were compared with rats fed a low fat (4.5%) diet.
Cardiac protein, DNA, phospholipid (PL) and fatty acid (FA) compositions were analyzed. Neutral phospholipase A, lysophospholipase
and creatine kinase activities in the membrane and cytosolic compartments were also investigated.
No significant modification of cardiac protein, DNA nor PL was observed among the three groups. Some alterations appeared
in the FA composition. A lard-enriched diet induced a significant increase of 22∶5n−3 and 22∶6n−3 in heart phosphatidylcholine
(PC) and phosphatidylethanolamine (PE), whereas a linoleic acid-rich diet induced a specific increase of 22∶4n−6 and 22∶5n−6
in these two major PL.
Compared to rats fed the low fat diet, membrane-associated phospholipase A activity, measured by endogenous hydrolysis of
membrane PC and PE, showed a significant increase (+45%) for both PL in rats fed corn oil. However, the activity of membrane-associated
phospholipases, measured with exogenous [1-14C]dioleoyl PC, was not different among the three groups of rats. Cytoplasmic activity was decreased in rats fed corn oil,
and lysophospholipase and creatine phosphate kinase activities were not significantly affected by diet.
FA modification of the long chain n−6 FA induced by corn oil may be responsible for the observed increase in phospholipase
activity. Physiological implications are suggested in terms of membrane degradation and prostaglandin production.
Presented in part at the International Symposium on Lipid Metabolism in the Normoxic and Ischemic Heart, Rotterdam, The Netherlands,
September 1986. 相似文献