共查询到20条相似文献,搜索用时 140 毫秒
1.
Because copper and iron have been reported to be essential cofactors in Δ9 desaturation of fatty acids, the effects of different
dietary intakes of copper and iron on tissue fatty acids were studied. Male Long-Evans rats (ten per group) were fed diets
containing adequate, deficient or excess copper or iron. On day 42 of the dietary regimen, the animals were killed and tissues
and blood were removed for analysis of metals and fatty acids of phospholipids. Compared with the copper-adequate rats, the
copper-deficient rats showed increased 18∶0 in liver and decreased 16∶1ω7 in liver, heart and serum. There were no differences
for 16∶0 or 18∶1ω9. Intake of excess copper did not cause an increase in products of Δ9 desaturation. Comparisons between
iron-deficient and iron-adequate rats showed that iron deficiency increased 18∶2ω6 in liver and serum and decreased 20∶4ω6
in serum only. Relative percentages of 16∶0, 18∶0, 16∶1ω7 and 18∶1ω9 in liver and serum phospholipids were similar for both
groups. Intake of excess iron caused a decrease in 18∶2ω6; and 16∶0 and 18∶1ω9 were higher in the liver of the iron-excess
group than the iron-deficient group. This study did not support the requirement for copper or iron in the Δ9 desaturation
of fatty acids as expressed in phospholipids of liver, heart and serum. 相似文献
2.
A. J. Sinclair 《Lipids》1974,9(10):809-818
The fatty acid composition of triglycerides and phospholipids from rat liver was determined throughout the period of growth
in the rat. Major changes in the triglyceride fatty acid composition were observed during the period studied. The triglycerides
from fetal and newborn rats contained only a small percentage of polyunsaturated acids compared with suckling and weanling
rats. During the suckling phase the liver triglycerides were rich in long chain polyunsaturated acids such as 20∶4, 20∶5,
22∶5, and 22∶6; once the pups were weaned, the percentage of these acids in the liver triglycerides fell. In these experiments,
18∶2 and 18∶3 were the only polyunsaturated acids in the maternal diet. However, the stomach contents of the suckling pups
contained 18∶2 and 18∶3, as well as the long chain polyunsaturated acids. Radioactive 18∶3 and 22∶6 were fed to suckling pups,
and the results suggested that the LCP in the rat liver triglycerides during the suckling period were derived from the long
chain polyunsaturated acids in the dam's milk, rather than by synthesis from either 18∶2 or 18∶3 within the pups. 相似文献
3.
Adria Rothman Sherman 《Lipids》1979,14(11):888-892
Serum lipids were studied in iron-deficient and control rats during suckling and after weaning at 21, 30, and 60 days of age.
Diets providing 5 or 307 ppm iron were fed to dams and their offspring during gestation, lactation, and after weaning. Rats
on the deficient diet throughout the experimental period developed a hyperlipidemia characterized by elevated triglycerides,
cholesterol, and phospholipids which was present at 21, 30, and 60 days. Control pups weaned to the deficient diet developed
anemia at 30 days of age and hypertriglyceridemia at 60 days of age. Repletion of deficient rats with iron after weaning caused
a rapid decline in serum lipid levels after only 9 days on the control diet. The hyperlipidemia of iron deficiency thus appears
to be reversible with iron supplementation. The time required to develop hypertriglyceridemia in iron deficiency is longer
postweaning than during suckling. 相似文献
4.
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
5.
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
6.
Male weanling rats were fed semipurified diets with and without essential fatty acid (EFA) and DDT (150 ppm) for 14 weeks
to determine the effects of the pesticide on physiological and biochemical aspects of EFA deficiency (EFAD). DDT did not affect
EFAD-induced reduction in growth rate or final body weight, nor did the pesticide affect EFAD-induced changes in feed efficiency
or skin dermatitis. The pesticide did increase liver/body mass ratios, but did not interact with EFAD, which also increased
this ratio. The pesticide produced complex changes in total fatty acid composition of liver and tail skin: liver levels of
18∶0, 18∶2 and 20∶3ω9 were increased, whereas levels of 12∶0, 14∶0 and 16∶0 were decreased. In both tissues, DDT interacted
with EFA to increase 18∶2 levels. DDT did not change the total fatty acid 20∶3ω9/20∶4ω6 ratio in either tissue. In this study,
although DDT did not exacerbate the physiological aspects of EFAD, DDT-induced changes in fatty acid composition of liver
and tail skin indicated that 150 ppm DDT in the diets did alter lipid metabolism of the rats in an unexplained manner.
Scientific contribution No. 811, Storrs Agricultural Experimental Station, University of Connecticut, Storrs, CT 06268. 相似文献
7.
Guinea pigs were fed one of three diets containing 10% black currant seed oil (a source of gamma-linolenic (18∶3 n−6) and
stearidonic (18∶4 n−3) acids), walnut oil or lard for 40 days. The fatty acid composition of liver triglycerides, free fatty
acids, cholesteryl esters, phosphatidylinositol, phosphatidylserine, cardiolipin, phosphatidylcholine and phosphatidylethanolamine
were determined.
Dietary n−3 fatty acids found esterified in liver lipids had been desaturated and elongated to longer chain analogues, notably
docosapentaenoic acid (22∶5 n−3) and docosahexaenoic acid (22∶6 n−3). When the diet contained low amounts of n−6 fatty acids,
proportionately more of the n−3 fatty acids were transformed. Significantly more eicosapentaenoic acid (EPA) (20∶5 n−3) was
incorporated into triglycerides, cholesteryl esters, phosphatidylcholine and phosphatidylethanolamine of the black currant
seed oil group compared with the walnut oil group.
Feeding black currant seed oil resulted in significant increases of dihomogamma-linolenic acid (20∶3 n−6) in all liver lipid
classes examined, whereas the levels of arachidonic acid (20∶4 n−6) remained relatively stable. The ratio dihomo-gamma-linolenic
acid/arachidonic acid was significantly (2.5-fold in PI to 17-fold in cholesteryl esters) higher in all lipid classes from
the black currant seed oil fed group. 相似文献
8.
Ikuo Ikeda Yoshiaki Tomari Michihiro Sugano Soichiro Watanabe Junichi Nagata 《Lipids》1991,26(5):369-373
The effects of various structured triglycerides containing medium-chain (caprylic or capric acids) and long-chain (linoleic
acid) fatty acids on fatty acid and cholesterol absorption were studied in lymph-cannulated rats. A considerable portion of
capric and caprylic acid was absorbed through the lymph duct, although to a lesser extent than was linoleic acid. Capric and
linoleic acid located at the 2-position of 2-decanoyl-1,3-dilinoleoyl-glycerol (18∶2/10∶0/18∶2) and 2-linoleoyl-1,3-didecanoyl-glycerol
(10∶0/18∶2/10∶0), respectively, tended to be absorbed more efficiently than those located at the 1- and 3-position or those
from tricaprin (10∶0/10∶0/10∶0) or trilinolein (18∶2/18∶2/18∶2). A similar trend was observed when the medium-chain fatty
acid was caprylic acid instead of capric acid. Caprylic acid absorption from 2-octanoyl-1,3-dilinoleoylglycerol (18∶2/8∶0/18∶2)
was significantly greater (p<0.05) than from 2-linoleoyl-1,3-dioctanoyl-glycerol (8∶0/18∶2/8∶0) or tricaprylin (8∶0/8∶0/8∶0).
Preferential absorption of caprylic and linoleic acid was not observed when the 1 to 2 and the 2 to 1 mixtures of 8∶0/8∶0/8∶0
and 18∶2/18∶2/18∶2, respectively, were administered. The structured lipids did not affect the lymphatic absorption of cholesterol.
The results suggest that structured triglycerides composed of medium-chain fatty acids and linoleic acid may be more useful
for the treatment of lipid malabsorption than are mixtures of medium-chain triglyceride (MCT) and long-chain triglycride (LCT). 相似文献
9.
Minimal deviation hepatoma 7288C cells were cultured in a modified Swim's medium supplemented with decreasing levels of serum,
lipid-free serum, lipid-free serum plus fatty acids, and other additives. Cellular and media neutral lipid classes were quantitated,
the fatty acids of triglycerides and sterol esters analyzed, and the carbon number distribution of triglycerides determined.
Cellular triglyceride biosynthesis virtually was inhibited when the medium was supplemented with bovine serum alone. This
inhibition was not observed when the medium was supplemented with fetal calf serum alone or mixtures of fetal calf serum and
bovine serum. Cells cultivated on medium supplemented with lipid-free serum plus palmitic or linoleic acids had much lower
levels of free and esterified cholesterol. The fatty acid composition of cellular triglycerides and cholesterol esters differed
dramatically from the corresponding media lipid classes. Except when linoleic acid was added to the medium, changes in the
media serum and lipid levels had only marginal effects upon the fatty acid composition of cellular triglycerides and cholesterol
esters. These data, in conjunction with earlier data that showed the media neutral lipid levels did not decrease during cell
growth, indicate that these hepatoma cells utilize little or no serum triglycerides and cholesterol esters. Linoleic acid
added to the medium dramatically reduced the level of 18∶1 acids in cellular triglycerides and cholesterol esters. Palmitic
acid added to the medium did not change the fatty acid compositions significantly. Comparison of experimentally determined
and calculated triglyceride carbon number percentages indicated a random distribution of fatty acids in this glyceride. The
fatty acid composition of cellular triglycerides was similar to the composition of the cholesterol esters. The lack of characteristic
and distinguishable compositions of these two classes that occur in most normal tissues suggests a loss of specificity in
the lipid metabolism of this neoplasm at the class level. 相似文献
10.
The objective of this study was to test the hypothesis that increasing maternal dietary 18∶3n−3 by decreasing the 18∶2n−6/18∶3n−3
ratio will increase the 18∶3n−3 and 22∶6n−3 content of the whole body, liver, skin (epidermis, dermis, and subcutaneous tissue),
epididymal fat pads, and muscles (arms and legs) of 2-wk-old rat pups. Sprague-Dawley dams at parturition were fed semipurified
diets containing either a low (18∶2n−6 to 18∶3n−3 ratio of 24.7∶1) or a high (18∶2n−6 to 18∶3n−3 ratio of 1.0∶1) 18∶3n−3 fatty
acid content. During the first 2 wk of life, rat pups received only their dams' milk. Fatty acid composition of the pups'
stomach contents (dams' milk), whole body, brain, liver, skin, epididymal fat pads, and muscles was determined. The stomach
fatty acid composition of 18∶3n−3 reflected the dams' diet. The content of 18∶3n−3 in whole body, brain, liver, skin, epididymal
fat pads, and muscles was significantly (P<0.05) greater in rat pups fed the high compared with the low 18∶3n−3 fatty acid diet. The 22∶6n−3 content of the whole body,
brain, skin, epididymal fat pads, and muscles was not quantitatively different in rat pups fed either the low or high 18∶3n−3
fatty acid diet. The 20∶5n−3 and 22∶5n−3 content of the whole body, skin, and epididymal fat pads was significantly increased
in rat pups fed the high compared with the low 18∶3n−3 fatty acid diet. High content of 18∶3n−3 was found in the skin of rat
pups fed either a low or high 18∶3n−3 fatty acid diet. These findings demonstrate that high maternal dietary 18∶3n−3 significantly
increases the 18∶3n−3 but not the 22∶6n−3 content of the whole body, brain, skin, epididymal fat pads, and muscles with approximately
39 and 41% of the whole body 18∶3n−3 content being deposited in the skin of suckling rat pups fed either the low or high 18∶3n−3
diet, respectively. 相似文献
11.
Male rats were fed on a fat-free diet for 8 weeks and then switched to diets containing 10% hydrogenated coconut oil (HCO),
safflower oil (SFO) or evening primrose oil (EPO). Half of each group was also given 1% of cholesterol in the diet. After
5 further weeks, plama, red cell and liver fatty acids were measured in the various lipid fractions. Plasma and liver cholesterol
also were estimated. In almost all fractions and on all three diets, feeding cholesterol led to accumulation of the substrates
of desaturation reactions and to deficits of the products of these reactions. The results were consistent with inhibition
of Δ-6, Δ-5 and Δ-4 desaturation of n−6 essential fatty acids. Since the diets were deficient in n−3 fatty acids, levels were
very low but were also consistent with inhibition of desaturation. In contrast, cholesterol had relatively less consistent
effects on 20∶3n−9, suggesting that desaturation of n−9 fatty acids was less inhibited. Plasma cholesterol levels rose sharply
in the HCO and SFO groups but not at all in the EPO group. EPO contains the product of Δ-6 desaturation, 18∶3n−6, suggesting
that conversion of linoleic acid to 18∶3n−6 and possibly to further metabolites may be important for the cholesterol-lowering
effect of polyunsaturates. 相似文献
12.
Trans, trans-linoleate at 50 and 100% of dietary fat decreased kidney size and altered its composition.Trans, trans-linoleate as the sole source of dietary fat imparied growth and caused more severe symptoms of essential fatty acid deficiency
than was observed with hydrogenated coconut oil (HCO). The concentration of renal cholesterol, phospholipids (PL), triglycerides
(TG) and cholesteryl esters (CE) were also decreased. Linoleic (18∶2), homo-γ-linolenic acid (20∶3n6) and arachidonic acid
(20∶4n6) were significantly depressed in lipid classes, especially in PL and CE, by dietarytrans, trans-linoleate. The increase in eicosatrienoate (20∶3n9), especially in PL and CE of kidneys of rats fed HCO (essential fatty
acid deficient), was slight in rats fed 100%trans, trans-linoleate, indicating that thetrans, trans acid probably inhibited acyl elongation and desaturation. 相似文献
13.
The objective of this study was to test the effect of a novel fatty acid mixture, enriched with myristoleic and palmitoleic
acids, on plasma lipoprotein cholesterol concentrations. Weanling pigs were assigned to one of six groups and each group received
a diet differing in fatty acid composition. Diets were fed for 35 days and contained 10 g added cornstarch/100 g (to provide
baseline data) or 10 g added fatty acids/100 g. For those diets containing added fatty acids, extracted lipids contained 36%
myristoleic plus palmitoleic acid combined (14∶1/16∶1 diet), 52% palmitic acid (16∶0 diet), 51% stearic acid (18∶0 diet),
47% oleic acid (18∶1 diet), or 38% linoleic acid (18∶2 diet). Witht the exception of the cornstarch diet, all diets contained
approximately 30% myristic acid. There were no significant differences in weight gain across treatment groups (P=0.22). All diets caused a significant increase in triglycerides and in total, low density lipoprotein, high density lipoprotein,
and very low density lipoprotein cholesterol. The increase in total plasma cholesterol from pretreatment values was greatest
in pigs fed the 14∶1/16∶1 and 18∶1 diets. However, the increase in low density lipoprotein cholesterol from the pretreatment
concentration was greatest in the 14∶1/16∶1-fed pigs. Increases in very low density lipoprotein cholesterol above pretreatment
concentrations were lowest in 16∶0-fed pigs and greatest in 18∶1-fed pigs. Dietary fatty acids elicited changes in plasma
fatty acids which generally were reflective of the diets, although the 18∶0 diet did not alter plasma fatty acid concentrations
and the 16∶0 diet increased plasma 16∶0 only at the end of the study. These results demonstrated that the combination of myristoleic
plus palmitoleic acids increased plasma cholesterol in young pigs, suggesting that fatty acid chain length, rather than degree
of unsaturation, is primarily responsible for the effects of fatty acids on circulating lipoprotein cholesterol concentrations. 相似文献
14.
Effects of pregnancy and lactation on lipid metabolism in mouse mammary fat pads and nonmammary adipose tissues have been
studied. In order to address the question whether the influence of hormonal milieu on lipid metabolism in mammary epithelial
cells during pregnancy and lactation is the same as in fat cells, we have studied the mobilization of lipids and metabolism
of fatty acids in the intact mammary glands, parenchyma-free mammary fat pads and in the perimetrial fat tissues of virgin,
pregnant and lactating mice. Compared to parenchyma-free mammary fat pads, the perimetrial adipose tissues accumulated 5-fold
higher levels of triglycerides during pregnancy. Mammary fat cells maintained overall lipid levels during pregnancy and lactation
(16–20 μg/fat pad). In contrast, lactation depleted total lipid stores from 108 ± 5 to 24 ± 4.5 μg/fat pad in perimetrial
fat pads. Results of comparative analysis of fatty acid composition of mammary fat pads, with and without epithelial tissue,
from virgin and lactating mice showed stimulation of 18∶2ω6 metabolism leading to 130% increase in the ratio 20∶4ω6 to 18∶2ω6
in the epithelial compartment. Pregnancy and lactation resulted in the elevation of 20∶4ω6 levels probably due to a 4-fold
increase in Δ5 desaturase activity and a decrease in oxidative degradation of 18∶2ω6. These results suggest that, unlike other
adipose tissues, the metabolic pathways in mammary fat cells are not dedicated to sequestration and accumulation of dietary
lipids during pregnancy. Lactation favors mammary epithelial cell-stimulated production of precursors of eicosanoids which
are known to have agonist-like effect on mammary epithelial cells. 相似文献
15.
Nanna Philipson Brandorff 《Lipids》1980,15(4):276-278
During pregnancy and lactation, female rats were fed diets containing either 28% partially hydrogenated marine oil (28MO),
2% arachis oil (2AO), or no fat (FF). Milk lipid composition was examined by gas chromatographic analysis of the gastric content
of 10-day-old suckling pups. An increase to 45% in the milk content of long chain monoenoic acids, 18∶1, 20∶1 and 22∶1, reflects
the fatty acid composition of the marine oil. Milk fatty acids of medium chain length comprised 6%, 31% and 24% of total fatty
acids in the (28MO), (2AO) and (FF) groups, respectively, suggesting that a high-fat diet (28MO) inhibits the lipid synthetic
activity of mammary glands. The amount of dienoic C18-acids (6%) in the group fed (28MO) containing no essential fatty acids (EFA) was similar to the amount of 18∶2 in the group
receiving a low-fat, EFA-rich diet (2AO). However, only half the dienoic acid from the milk of the (28MO)-fed animals was
linoleic acid, which was most likely mobilized from fat depots. 相似文献
16.
Ikuo Ikeda Jun Murakami Takayuki Oka Michihiro Sugano Hideaki Yamada Sakayu Shimizu Hiroshi Kawashima Yoshifumi Shinmen Teruo Amachi 《Lipids》1991,26(1):27-30
The effects of perfused oleic (18∶1n−9), arachidonic (20∶4n−6) and 5,8,11,14-nonadecatetraenoic (19∶4n−5) acids on triglyceride
and cholesterol secretion and ketone body production were studied in isolated rat liver. As compared to oleic and 19∶4n−5
acids, both ketone body production and triglyceride secretion were significantly lowered when arachidonic acid was perfused.
The concentration of triglyceride in the post-perfused liver was lower upon perfusion with arachidonic acid than upon perfusion
with oleic acid or 19∶4n−5 acid. Cholesterol secretion in the liver perfused with arachidonic acid or 19∶4n−5 acid was significantly
higher than with oleic acid. The concentration of cholesterol in the post-perfused liver was slightly but significantly higher
with 19∶4n−5 acid than with the other fatty acids. The results suggest that 19∶4n−5 acid when compared with arachidonic acid
affects lipid metabolism in liver differently. 相似文献
17.
Steers were given diets containing formaldehyde-treated casein-safflower oil supplements, in which the constituent 18∶2 was
protected from ruminal hydrogenation. A similar group was given unsupplemented diets. The fatty acid compositions of plasma,
liver, muscle and adipose tissue lipids were determined in both groups of cattle after 0, 2, 4 and 8 weeks of experimentation.
The proportion of 18∶2 in the triglycerides was markedly increased on feeding the supplement and the rate of incorporation
into the plasma triglycerides was higher than that in the triglycerides of muscle and adipose tissue. Associated with this
increase there were compensatory decreases in the proportions of 16∶0 and 18∶1 but no consistent change in the proportion
of 18∶0. The proportion of 18∶2 in the plasma phospholipids and cholesteryl esters was initially much higher than in the triglycerides
and this was further increased by feeding the safflower oil supplement. A linear relationship existed between the proportion
of 18∶2 in the phospholipids and cholesteryl esters of plasma. The supplement also caused substantial increases in the proportion
of 18∶2, both in phospholipids from liver and muscle and in cholesteryl esters from liver, and there were compensatory decreases
in the proportions of other unsaturated fatty acids, e.g., 18∶1, 18∶3, 22∶6. These studies demonstrate that when ruminal hydrogenation
was circumvented by feeding formaldehyde-treated casein-safflower oil particles, the linoleic acid was absorbed and the pattern
of incorporation into plasma and tissue lipids was similar to that in nonruminants. 相似文献
18.
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
19.
The present study examined the effects of two atherogenic factors, animal protein and cholesterol, on the distribution of
fatty acids and the molecular species of major liver phospholipids in mice. Weanling mice were fed a semisynthetic diet supplemented
with either casein or soy protein (20%, w/w) in the presence or absence of 0.5% cholesterol for 4 wk. Results from mouse liver
showed that animal protein and, more so, dietary cholesterol modified the fatty acid profiles of the phospholipids. Animal
protein had no significant effect on the concentration of lipids, but it altered the relative distribution and fatty acid
profiles of the phospholipids, phosphatidylcholine and phosphatidylethanolamine. Dietary cholesterol, on the other hand, significantly
increased the concentration of liver lipids, but it did not alter the relative distribution of phosphatidylcholine and phosphatidylethanolamine.
In cholesterol-fed mice, the proportions of molecular species containing 18∶2n−6 were increased, whereas those containing
20∶4n−6 were decreased, indicating that dietary cholesterol suppressed linoleic acid metabolism. Since cholesterol feeding
selectively decreased the ratio of 18∶0/20∶4n−6 in phosphatidylcholine, whereas it increased the 18∶0/18∶2n−6 ratio in phosphatidylethanolamine,
this finding suggests that dietary cholesterol may affect the incorporation of fatty acids but not the rate of synthesis of
phosphatidylcholine and phosphatidylethanolamine. 相似文献
20.
The fatty acid composition of liver, heart, and testes was determined in gerbils maintained on a fat-deficient or fatsupplemented
diet since the age of twenty-eight days and in gerbil pups, the mothers of which were placed on the respective diets on the
day of delivery. Pups born to these mothers were killed at 11 to 19 days at which time increased concentrations of 16∶1, 18∶1,
and 20∶3ω9 and decreased concentrations of 18∶2 and 20∶4 (and 22∶5ω6 in testes) were apparent in organs of fat-deficient compared
to fat-supplemented gerbils. Similar but more marked changes occurred in organs of gerbils placed on the fat-deficient diet
at twenty-eight days of age and examined at intervals of time up to two months later. In these animals, minimal changes were
seen also in fatty acids of the brain. The concentration of 22∶6ω3 was resistant to change with the fat-deficient diet. Deficient
gerbils had hair loss, decreased quantities of spermatids and spermatozoa in the testis, and most but not all had decreased
body weight compared to the fat-supplemented controls. Extremely high concentrations of oleic acid were present in carcass
fatty acids of deficient compared to supplemented gerbils, indicating an extremely dynamic fatty acid metabolism in these
animals. 相似文献