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1.
The influence of dietary restriction on cholesterol transport and metabolism was investigated in rabbits given standard or
cholesterol-rich diets (0.2 g cholesterol/kg body weight daily) eitherad libitum or with 50% caloric ration. Dietary restriction which has only a slight influence in control rabbits markedly aggravated
the disturbances induced by exogenous cholesterol. With limited feeding, control rabbits presented a moderate increase in
plasma cholesterol, whereas marked aggravation of hypercholesterolemia was observed in cholesterol-fed rabbits. Analysis of
the lipoprotein profile showed that the excess of plasma cholesterol with the restricted cholesterol-rich diet corresponded
to an increase in the concentration of very low density lipoprotein (VLDL) and low density lipoproteins (LDL) without any
additional changes in the composition of these lipoproteins. No significant change appeared in the high density lipoprotein
(HDL) concentration. The parameters of cholesterol metabolism were determined, from the curves of [3H] cholesterol radioactivity decrease, using a two-pool model. The increase in cholesterol turnover rate induced by the cholesterol-rich
diet was accentuated by dietary restriction, whereas rabbits on standard restricted diet showed a slight decrease. The large
increase in the size of both pools A and B in cholesterol-fed rabbits was even more pronounced with limited feeding. Dietary
restriction induced additional accumulation of cholesterol in the aortic wall and the grade of the lesions was also aggravated. 相似文献
2.
Dietary restriction (half of the control ration) was performed in rabbits given either standard or cholesterol-rich diets.
The plasma apolipoproteins were studied on the total, d<1.21, lipoprotein fraction using polyacrylamide gel electrophoresis.
A marked rise in the amount of both apo-B and apo-E appeared in cholesterol-fed rabbits and was enhanced by dietary restriction.
These results reflect the aggravation of hypercholesterolemia when cholesterol feeding is carried out in underfed rabbits.
In all groups only one molecular species of apo-B, identified as apo-B-100, was present after overnight fasting. Thus, lipoproteins
which accumulate in the plasma following cholesterol feeding, associated with dietary restriction or not, probably are remnants
of hepatogenous triglyceride-rich lipoproteins. 相似文献
3.
In two inbred strains of rabbits with high or low response of plasma cholesterol to dietary saturatedversus polyunsaturated fatty acids, the efficiency of intestinal cholesterol absorption was measured. The feeding of a cholesterol-free
purified diet containing saturated fatty acids in the form of coconut fat, when compared with a diet containing corn oil as
polyunsaturated fatty acids, did not influence the efficiency of cholesterol absorption in the two rabbit strains. Irrespective
of the dietary fat source, the hyperresponsive rabbits absorbed cholesterol more efficiently. It is concluded that the hypercholesterolemic
effect of dietary coconut fatversus corn oil is not exerted by influencing cholesterol absorption. 相似文献
4.
To investigate the effects of dietary fat quality on synthesis and esterification of cholesterol, Syrian hamsters were fed
diets containing corn, olive, coconut or menhaden oils (10% w/w) with added cholesterol (0.1% w/w). After 3 weeks, animals
were sacrificed 90 min following IP injection of3H2O. Synthesis of free cholesterol and movement of free cholesterol into ester pools were measured from3H-uptade rate in liver and duodenum. Plasma total cholesterol and triglycerides levels were highest in coconut oil-fed animals,
whereas hepatic total cholesterol and ester levels were elevated in olive oil-fed animals, as compared with all other groups.
No diet-related differences were seen in duodenal cholesterol or total fatty acid content. In duodenum, uptake of3H per g tissue into cholesterol was greater compared with liver; however, within each tissue,3H-uptake into cholesterol was similar across groups. Notably,3H-uptake into cholesterol ester in liver was highest in menhaden oil-fed animals. These data suggest that menhaden fish oil
consumption results in enhanced movement of newly synthesized cholesterol into ester as compared with other fat types. 相似文献
5.
P. E. Mone W. D. Warner C. E. Poling E. E. Rice 《Journal of the American Oil Chemists' Society》1959,36(4):141-142
Summary Cottonseed oil, partially hydrogenated cottonseed oil and corn oil, were fed at 4% and 10% of the diets with two levels of
protein, 19% and 25%, and with 0.5% cholesterol to cockerels 21 days of age for a period of 38 days. Blood samples were obtained
at 0, 14, 24, and 38 daysvia heart puncture.
The data indicate that the serum cholesterol value, irrespective of the level or type of fat, was significantly lower in those
groups of birds which were fed the higher level of protein. Excluding the combination of 19% protein and 10% cottonseed oil,
the degree of saturation did not have any apparent effect upon serum cholesterol because the mean differences among the oils
and between the fat levels were not statistically significant. 相似文献
6.
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
7.
G. W. Meijer A. F. H. Stalenhoef P. N. M. Demacker M. J. T. M. Mol L. F. M. Van Zutphen A. C. Beynen 《Lipids》1992,27(6):474-477
In two inbred strains of rabbits with high or low response of plasma cholesterol to dietary cholesterol, low density lipoprotein
(LDL) apolipoprotein (apoLDL) kinetics were determined with the use of a heterologous tracer isolated from a Watanabe heritable
hyperlipidemic (WHHL) rabbit. On a diet without added cholesterol, the total clearance of apoLDL (which equals apoLDL production)
did not differ significantly between rabbits of both strains. After the feeding of a diet containing 0.1% cholesterol for
six weeks, plasma LDL cholesterol, plasma apoLDL and liver cholesterol concentrations rose significantly in the hyperresponsive
but not in the hyporesponsive rabbits. Cholesterol feeding depressed the total fractional catabolic rate (FCR) of apoLDL in
the hyper- but not in the hyporesponsive rabbits; this was attributed to a decrease of receptor-dependent FCR while receptor-independent
FCR was similar in the two strains. On the diet containing cholesterol, the receptor-mediated absolute catabolic rate (ACR)
of apoLDL did not differ between hyper- and hyporesponsive rabbits but receptor-independent ACR of apoLDL was higher in hyperresponders.
It is concluded that the higher plasma apoLDL levels in hyperresponsive rabbits fed the 0.1% cholesterol diet are caused by
a higher production of apoLDL and not by a lower flux of apoLDL through the receptor-mediated pathway. 相似文献
8.
Influence of dietary saturated fatty acids on the regulation of plasma cholesterol concentration 总被引:1,自引:1,他引:0
The specific effects of individual fatty acids (FA) on plasma cholesterol levels, in the range habitually consumed by humans,
is not usually presented by the literature. Conclusions have been made regarding the cholesterolemic effect of individual
FA, even though these FA cannot be tested individually. It appears that FA balance of the diet may be more important than
individual FA intakes. Variation in plasma cholesterol response to diet is influenced by many factors, such as gene-nutrient
interactions. The effect on human health of current processes used in the food industry that are certain to change dietary
fat composition and TG structure is yet to be fully explored. Some of the relevant research regarding dietary fat and plasma
cholesterol levels is reviewed. 相似文献
9.
Peanut oil has been shown to be unexpectedly atherogenic for cholesterol-fed rats, rabbits and rhesus monkeys. However, randomization
(rearrangement of fatty acids to random distribution) of peanut oil significantly reduced its atherogenicity for rabbits and
monkeys. This study was conducted to investigate whether the absorption and transport of dietary cholesterol was altered in
the presence of peanut oil or randomized peanut oil, thereby accounting for the difference in the atherogenicity of the two
diets. Intestinal lymph fistula rats were infused intraduodenally with a lipid emulsion at a rate of 3 ml/hr. The lipid emulsion
contained either peanut oil (control) or randomized peanut oil (experimental) (10 mM),14C-cholesterol (1.3 mM) and sodium taurocholate (19 mM) in phosphate-buffered saline, pH 6.4. Lymph triglyceride, cholesterol
and phospholipid outputs were similar in both groups of rats during fasting and subsequently during lipid infusion. Comparable
recovery of14C-cholesterol from the intestinal lumen and the intestinal mucosa of the control and the experimental rats showed that the
absorotion and transport of dietary cholesterol were similar in both groups of rats. Analyses of thefatty acid of both lymph
and intestinal mucosal lipid again failed to reveal a difference between the 2 groups of rats. It is concluded that the difference
in the atherogenicity between the peanut oil and the randomized peanut oil is probably caused by events subsequent to the
release of cholesterol containing chylomicrons and very low density lipoproteins by the small intestinal epithelial cells. 相似文献
10.
The fate of an oral dose of [4-14C] cholesterol given to rats grown on diets with 20% safflower oil or 20% hydrogenated coconut oil was determined by analysis
of digestive tract, feces and tissues. The pattern of isotope distribution did not support the view that rats fed a saturated
fat absorb less cholesterol than those fed an unsaturated fat. Fasted animals growth on the diet with 5% of these two fats
and beef fallow showed no clear difference in the amount of digitonin-peecipitable sterol in their intestines. A shorter transit
time for intestinal contents was observed with the saturated fat groups. It is concluded that neither absorption of cholesterol
from the gut nor secretion of β-hydroxy sterol into the gut accounts for the hypocholesterolemic effect of polyunsaturated
fat.
Journal Paper No. 4951 AES, Purdue University. 相似文献
11.
12.
13.
The aim of the present study was to determine whether increased output of phospholipid in bile during aging may be due to
alteration of bile acid composition and stimulated hydrophobic bile acid formation. In female Sprague-Dawley rats we examined
the influence of aging and life long dietary restriction (60% of thead libitum intake) on bile flow, total bile acid secretion, bile acid composition and conjugation pattern, as well as phospholipid output.
Rats were cannulated at 3.5, 8–12 and 24–27 months of age and bile collected for analysis. With age, there was a significant
reduction in bile flow and total bile acid secretion, however, phospholipid output increased. Restriction of dietary intake
exerted a beneficial effect on the age-related decline in bile formation. Studies of bile composition indicated that 12α-hydroxylated
bile acids (cholic acid and deoxycholic acid) secretion decreased in aged rats compared to 3.5-month-old rats. This was associated
with a corresponding increase in secretion of chenodeoxycholic acid and hyodeoxycholic-ursodeoxycholic acid. However, the
magnitude of the change in secretion of these bile acids could not account for the increased output of phospholipid in bile. 相似文献
14.
The absorption of cholesterol and of cholesterol oxidation products (oxidized cholesterols) was compared in lymph-cannulated
rats. We found that the lymphatic absorption of an intragastrically administered, emulsified lipid meal containing 25 mg of
cholesterol or 25 mg of oxidized cholesterols, within 24 h, was approximately 67 and 30%, respectively. The absorption rate
of individual oxidized cholesterols differed considerably and was approximately 30% for 7α-hydroxycholesterol, 42% for 7β-hydroxycholesterol,
32% for 5β-epoxycholesterol, 28% for 5α-epoxycholesterol, 15% for cholestanetriol and 12% for 7-ketocholesterol. Moreover,
cholesterol oxidation products delayed the absorption of oleic acid as triolein. Approximately 35 and 48% of cholesterol was
recovered in chylomicrons (CM) and very low density lipoprotein (VLDL), respectively. In contrast, 54 and 40% of the oxidized
cholesterols was recovered in CM and VLDL, respectively, although there was a significant difference in the distribution of
individual oxidized cholesterols. The results of the present study indicate that oxidized cholesterols are absorbed to a lesser
extent than is cholesterol, that they disturb fat absorption and that they distribute differently between lymphatic lipoproteins. 相似文献
15.
Infusion of bile containing labeled cholesterol into bile fistula rats has permitted an in vivo study of the movements and
of the absorption of biliary cholesterol in the digestive tract. The specific activities of cholesterol were similar in the
micelles and the sediment of the luminal content after a 6 hr infusion, indicating rapid exchange of cholesterol between these
fractions. In animals fed a basal diet, the biliary cholesterol absorption was higher (83%) than that of dietary cholesterol
(70%). Bile cholesterol is essentially absorbed in the jejunum while the absorption of cholesterol from the diet takes place
all along the small intestine but preferentially in its second and third quarters. Both alimentary cholesterol and bile cholesterol
enter the top cells of the villi in preference to those of the crypts. In L-thyroxin-fed rats, a parallel decrease in biliary
and dietary cholesterol absorption was observed. The increase in the intestinal transit of cholesterol and epithelium cell
renewal of the jejunum accounted for this observation. 相似文献
16.
17.
Dietary supplements containing cholesterol or sunflower oil were prepared to protect them against degradation in the rumen.
On feeding daily supplements containing 1–2 g protected cholesterol and/or 100g protected sunflower oil to sheep, along with
a basal ration of crushed oat grain and lucerne chaff, a rise in the plasma cholesterol was observed when compared with control
animals. Livers from sheep fed protected cholesterol were enlarged, friable and cirrhotic in appearance and contained large
deposits of esterified and free cholesterol, while livers from animals fed protected sunflower oil alone contained much less
cholesterol. Octadecenoates constituted the major fatty acids in cholesterol esters, which, in animals fed protected sunflower
oil, were mainly polyunsaturated. The factors involved in the deposition of liver lipid at very low dietary cholesterol concentrations
(0.11–22%) in sheep compared with monogastric animals are discussed.
Deceased. 相似文献
18.
The influence of feeding cholesterol to rats during pregnancy and postpartum (from the 11th day of gestation to the third
day after delivery) on the serum and hepatic cholesterol levels and on the bile acid composition in the pool and in the liver
in relationship to the dams and their pups was examined. The hepatic content of cholesterol in both dam and offspring increased
during cholesterol feeding without any changes in serum cholesterol level. In the dams, mainly the esterified cholesterol
was increased; in the pups, mainly the free cholesterol was increased. Cholesterol feeding led to a pronounced increase in
the pool of β-muricholic acid and a relative decrease in the lithocholic acid concentration in pregnant rats. In fetal rats,
the chenodeoxycholic acid pool was increased by cholesterol intake. The lithocholic acid pool was larger in the postpartum
rats fed cholesterol than in the controls, while the concentration of α- and β-muricholic acids was decreased. The neonates
of cholesterol-fed dams had a larger pool of chenodeoxycholic acid but a smaller pool of β-muricholic acid. These results
suggest that the metabolism of cholesterol and of bile acids in dams and their offspring respond differently to cholesterol
intake. 相似文献
19.
Male Sprague-Dawley rats were fed a cholesterol-free (Exp. 1) or cholesterol-supplemented (Exp. 2) diet containing 20% casein
(control group) or 15% defatted squid and 5% casein (defatted squid group), as protein, for 14 d. Serum and hepatic cholesterol
concentrations were lower in rats fed defatted squid than in those fed casein in both cholesterol-free (−20%, P<0.05 and −15%, P<0.05, respectively) and cholesterol-supplemented (−25%, P<0.05 and −15%, P<0.05, respectively) diets. Hepatic triglyceride concentration was lower in the defatted squid than in the control groups
in both cholesterol-free (−51%, P<0.05) and cholesterol-supplemented diets (−38%, P<0.01). The activities of cytosolic fatty acid synthase and the NADPH-generating enzymes, malic enzyme and glucose-6-phosphate
dehydrogenase, in the liver were lower in the defatted squid than in the control groups in both cholesterol-free (−21%, P<0.01, −33%, P<0.05, and −33%, P<0.01, respectively) and cholesterol-supplemented diets (−34%, P<0.05, −57%, P<0.05, and −67%, P<0.05, respectively). The activity of mitochondrial carnitine palmitoyltransferase in the liver was comparable between the
control and defatted squid groups. The activity of Mg2+-dependent phosphatidate phosphohydrolase in the liver cytosol was lower in the defatted squid (−9%, P<0.05) than in the control groups only in the cholesterol-free diet. Fecal excretion of total steroids was stimulated by the
feeding of defatted squid in both cholesterol-free (+77%, P<0.005) and cholesterol-supplemented diets (+29%, P<0.01). These results suggest that the nonlipid fraction of squid exerts a hypocholesterolemic effect by increasing the excretion
of total steroids in feces. The fraction also induces a triglyceride-lowering activity in the liver by decreasing hepatic
lipogenesis. 相似文献
20.
Feeding 1–2 g/day of cholesterol protected against ruminal hydrogenation caused a 20–30% drop in the secretion of milk fat
by goats and cows. The effect was observed with goats fed conventional rations or with goats and cows fed rations supplemented
with protected lipids, but was not observed with cows fed conventional rations, or when unprotected cholesterol and protected
β-sitosterol was fed to these animals. The results suggest that this depression in milk fat is due to a decreased uptake of
plasma triacylglycerol fatty acids by the mammary gland, induced by dietary cholesterol. 相似文献