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1.
Frank P. Bell 《Lipids》1976,11(10):769-773
Di-2-ethylhexyl phthalate (DEHP), a commonly used plasticizer, was found to be an inhibitor of the biosynthesis of hepatic
nonsaponifiable lipids in the rat. The addition of DEHP at levels of 0.5% or 1.0% to a stock diet of rats resulted in a decreased
conversion of acetate-1-14C and mevalonate-5-3H into squalene, C30 sterols, and C27 sterols by liver minces or slices, in vitro. In studies conducted with 0.5% DEHP feeding from 2 to 11 days, the degree of
inhibition was found to increase with the duration of DEHP feeding; the inhibition of3H-mevalonate conversion to squalene and sterols developed more slowly, being reduced to ca. 70% of control values in 11 days,
whereas14C-acetate conversion was reduced to ca. 35% of control values during the same period.3H-mevalonate conversion to sterols and squalene was, however, found to be suppressable to the same extent as14C-acetate conversion when diets containing 1.0% DEHP were fed for 18 days. The inhibitory effect of dietary DEHP on sterol
and squalene biosynthesis from14C-acetate and3H-mevalonate by rat liver preparations is unlikely to be accounted for by the negative feedback of cholesterol secondary to
hepatic sterol accumulation since, in these studies, hepatic total lipid and hepatic total sterol levels were simialr in control
and DEHP-fed rats. 相似文献
2.
The hypocholesteremic activity of garlic was tested by incorporating freeze-dried garlic powder at 0.5, 1.0, 2.0 and 3.0%
levels in an atherogenic diet fed to rats. It was observed that 0.5 and 1.0% levels were not effective whereas the other 2
levels were. The group fed 2.0% garlic powder had much lower serum cholesterol level than the one fed 3%. The increased levels
of low density lipoproteins (LDL) and LDL-cholesterol in rats fed the atherogenic diet were partly reversed in rats receiving
a supplement of 2% garlic powder. On a cholesterol-containing diet, high density lipoproteins (HDL) and HDL-cholesterol levels
were decreased. Inclusion of garlic powder in the atherogenic diet enhanced the percentage of HDL whereas no change was observed
in HDL cholesterol levels. Commercial garlic pearls (equivalent to 0.15% garlic powder in the diet) produced a significant
decrease in serum and liver cholesterol levels in rats fed the atherogenic diet. On the other hand, asafoetida at 1.5% level
failed to reduce the serum cholesterol levels in the cholesterol-fed rats. 相似文献
3.
Male albino rats were administered various oral doses of tibric acid daily for 1 week. Serum cholesterol and triglyceride
levels were reduced, but total liver content of cholesterol, phospholipids, and triglycerides was increased. Tibric acid treatment
suppressed the incorporation of both [14C] acetate and [3H] mevalonate into cholesterol by liver homogenates. 相似文献
4.
S. N. Shah 《Lipids》1973,8(5):284-288
The conversion of mevalonic acid into total nonsaponifiable lipids (NSF) and digitonin precipitable sterols (DPS) by 5000
g liver supernatant fractions was compared in suckling and weaned rats. The incorporation of mevalonate into both NSF and
DPS was low in fractions from suckling rats and very high in fractions from weaned rats. The results indicate that the activities
of one or more of the enzymes catalyzing the conversion of mevalonate into squalene and squalene into cholesterol change after
weaning and may act as regulatory step(s) for cholesterol synthesis in the livers of suckling rats. It is suggested that the
reduced synthesis of cholesterol in the liver of suckling rats is caused by the cholesterol in the maternal milk, and the
rapid rise in cholesterol synthesis after weaning is due in part to the dietary change accompanying weaning, and in part to
an increased need for cholesterol by developing liver. 相似文献
5.
6.
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
7.
Kurokawa M Masuda Y Noda M Marushima R Usuda M Takeda S Hasegawa M Homma Y Sugano M 《Journal of oleo science》2008,57(1):23-33
We examined the minimal effective dose on serum cholesterol concentration and the safety of dressing containing plant sterol in humans. EXP.1: Sixty-eight healthy Japanese males (total cholesterol (TC) > or = 170 mg/dL) were randomly divided into four groups, and were given 0, 400, 800 or 1200 mg/day of plant sterol in 15 g dressing for 4 weeks followed by the washout period of 4 weeks. Although there were no significant differences in serum TC and low-density lipoprotein cholesterol (LDL-C) concentrations among all groups after feeding plant sterol for 4 weeks, in 36 subjects with TC > or = 220 mg/dL, serum LDL-C concentration tended to reduce when received 800 or 1200 mg of plant sterol, and the difference between 0 and 1200 mg groups was statistically significant. The difference between 0 and 800 mg groups was near significant (p=0.053). Intake of 400 mg of plant sterol did not change serum LDL-C concentration. EXP.2: Twenty-one healthy Japanese subjects (TC > or = 180 mg/dL, 10 men, 11 women) were given 2400 mg/day of plant sterol in 45 g dressing for 4 weeks. Clinical data were all remained normal. These results indicated that minimal effective dose of the plant sterol on serum cholesterol concentration in healthy male subjects is around 800 mg/day, and intake of 2400 mg/day of plant sterol is regarded to be safe. 相似文献
8.
9.
Studies of cholesterol levels in a population of Gran Buenos Aires was made in 1983, 1988, 1993 and 1996, and the Argentinian alimentary habits in this period were analyzed. It was noticed a change in food consumption, with reduction in the intake of fatty foods, such as meat, butter, milk, and other dairy products, with the concomitant increment in fiber rich products and oil, meat and dairy products reduced in fats. Changes in serum cholesterol level were analysed in 3051 persons along 1983-1996. They were grouped according their age and sex: A) 1-6 years old, B) 6-12, C) 12-17, D) 17-30, E) 30-60, F) 60-80. It was observed an increment in cholesterol level with age. For each group during the first 10 years of study was noticed a constant decrease in total cholesterol being higher in women than in men and according with the alimentary changes. Group D in 1983 became group E in 1993, maintained their cholesterol level along 10 years of life, being lower than the corresponding E group of 1983, while the older ones did not present differences. Values of cholesterol/cholesterol-HDL index over 6.5 correlate with a high incidence in cardiovascular diseases. The 40% of the population studied during 1993 and 1996 was evaluated, and the maximum average value found was 4.90. These results suggest that reduction in fat intake and diversification in food consumption during this period has contributed to decrease cholesterol levels and cholesterol/cholesterol-HDL index, particularly in younger than 30 years old and women, contributing to reduce metabolical cardiovascular diseases. 相似文献
10.
Ruvini Liyanage Kyu‐Ho Han Ken‐ichiro Shimada Mitsuo Sekikawa Yoshihiko Tokuji Kiyoshi Ohba Keiko Sasaki Barana Chaminda Jayawardana Takashi Shimizu Michihiro Fukushima 《European Journal of Lipid Science and Technology》2009,111(9):884-892
We examined the effect of potato peptides (PPC) in rats fed a cholesterol‐enriched diet, in comparison with two cholesterol‐enriched diets containing soy peptides (SPC) or casein (CNC), and a cholesterol‐free diet containing casein (CN) for 4 weeks. The serum non‐high‐density lipoprotein (HDL) cholesterol level was lower in the PPC‐ (–18.39%) and SPC‐fed (–32.76%) groups (p <0.05) than in the CNC‐fed group at the end of the feeding period. The low‐density lipoprotein receptor mRNA level in the PPC‐fed group, and cholesterol 7α‐hydroxylase and scavenger receptor class B type 1 mRNA levels in the SPC‐fed group, were higher (p <0.05) than in the CN‐ and CNC‐fed groups. Faecal neutral sterol and caecal short‐chain fatty acid concentrations in the PPC‐ and SPC‐fed groups were higher (p <0.05) than in the CN‐ and CNC‐fed groups. The faecal total acidic sterol concentration was higher in the SPC‐fed group than in the CN‐ and PPC‐fed groups. Caecal anaerobe and Bifidobacterium populations were higher (p <0.05) in the PPC‐ and SPC‐fed groups than in the CN‐fed group. This study suggests that potato peptides, as soy peptides, alter caecal fermentation and steroid absorption and reduce the serum non‐HDL cholesterol level in rats fed cholesterol. 相似文献
11.
Kurokawa M Masuda Y Noda M Usuda M Takeda S Hasegawa M Homma Y Sugano M 《Journal of oleo science》2008,57(1):35-45
In a placebo-controlled double-blind study, we examined the effects of dressing containing plant sterol (PS) on blood lipids and the safety in Japanese borderline or mildly hypercholesterolemic subjects. Fifty-nine subjects [total cholesterol (TC) concentration > or = 200 mg/dL] were randomly divided into two groups and were given daily 15 g of dressing containing 800 mg of PS [PS(+)-group] or without PS [PS(-)-group] for 12 weeks. Every 4 weeks, fasting blood was examined and subjective symptoms were analyzed. Serum TC, low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) concentrations did not change in the PS(-)-group, while TC and ApoB significantly decreased in the PS(+)-group at 8 and 12 weeks and LDL-C at 4, 8 and 12 weeks. Moreover, serum TC, LDL-C and ApoB concentrations were significantly lower than those of PS(-)-group at 8 and 12 weeks. Other laboratory tests were all in normal ranges and no adverse events were observed. The results indicated that PS-containing dressing decreased serum TC, LDL-C and ApoB concentrations in borderline or mildly hypercholesterolemic subjects. It is therefore proved that the dressing containing PS is helpful in maintaining blood cholesterol level normal and hence, the health of Japanese. 相似文献
12.
Ingestion of plasmalogen markedly increased plasmalogen levels of blood plasma in rats 总被引:1,自引:0,他引:1
Plasmalogens, a subclass of phospholipids, are widely distributed in human and animals, and are taken into the body as food.
However, no data exist on the intestinal absorption or fate of ingested plasmalogen. Here, we determined whether dietary plasmalogen
is absorbed and whether blood and tissue concentrations increased in normal male Wistar rats by using four separate experiments.
Phospholipids containing more than 20 wt% of plasmalogen extracted from the bovine brain were incorporated into test diets
(10–15 wt%). In experiment 1, we estimated the absorption rate by measuring the plasmalogen vinyl ether bonds remaining in
the alimentary tract of rats after the ingestion of 2 g of test diet containing 91 μmol plasmalogen. The absorption rate of
plasmalogen was nearly 80 mol% after 4 h, comparable to the total phospholipid content in the test diet. In experiment 2,
we observed no degradation of the plasmalogen vinyl ether bonds under in vitro conditions simulating those of the stomach and small intestinal lumen. In experiment 3 we confirmed a comparable absorption
(36 mol%) by using a closed loop of the upper small intestine in anesthetized rats 90 min after injecting a 10 wt% brain phospholipid
emulsion. Feeding a test diet containing 10 wt% brain phospholipids for 7 d increased plasmalogen concentration threefold
in blood plasma and by 25% in the liver; however, no increases were seen in blood cells, skeletal muscle, brain, lungs, kidneys,
or adipose tissue (experiment 4). We concluded that dietary plasmalogen is absorbed from the intestine and contributes to
a large increase in plasmalogen levels in blood plasma. 相似文献
13.
Rats were fed plant sterols containing campesterol and β-sitosterol in the different proportions, and their distribution in
serum lipoproteins and in liver subcellular fractions was determined. In serum lipoproteins, the percentage as well as the
concentration of plant sterols increased with the increase in the density of lipoproteins. Thus, high density lipoprotein
(HDL) contained the highest and very low density lipoprotein (VLDL), the lowest. Also, there were distinct differences in
the ratio of campesterol to sitosterol among lipoproteins, it was the highest in VLDL and lowest in HDL. Quantitatively, more
than 75% of campesterol and 80% of sitosterol were carried in HDL; the values were significantly different from those of cholesterol
(ca. 70%) in relation to total cholesterol. The distribution of plant sterols in liver subcellular fractions was virtually
the same with that of cholesterol. Both nuclei and microsomes contained approximately 40% of total plant stetols.
A preliminary part of the study was presented at the First Congress of the Federation of Asian and Oceanian Biochemists in
Nagoya, October 1977. 相似文献
14.
Fifty-two male guinea pigs fed on a scorbutigenic diet were divided into a control group (10 mg ascorbicacid per animal per
day) and a group with latent vitamin C deficiency (2 weeks on the scorbutigenic diet only, followed by a maintaining dose
of 0.5 mg ascorbic acid per animal per day). After 13 weeks, 26-14C-cholesterol was administered intraperitoneally to all the animals, in which the14C excretion in the expired CO2 and the urine and cholesterol specific activity in the blood serum and liver were then studied at intervals of 24 hr and
1, 3, 5, 7, 9 and 11 weeks. The ascorbic acid concentration in the liver and spleen of the control animals was five times
higher than in vitain C-deficient animals. The total cholesterol concentration in serum and liver was significantly higher
in the vitamin C-deficient guinea pigs. A two-pool analysis of the disappearance curves of serum cholesterol specific activity
showed that the size of the cholesterol pool A (blood and tissues with rapid cholesterol exchange) was greater in the vitamin
C-deficient animals. The rate of the transformation of cholesterol to bile acids was estimated as the ratio of14CO2 expired to liver cholesterol specific activity. Latent vitamin C deficiency caused significant slowing down of this process
(controls: 11.8±0.6; vitamin C deficiency: 8.3±0.4 mg/24 r/500 g w/w). A significant correlation between the liver ascorbic
acid concentration and the rate of cholesterol transformation to bile acids was found. The results demonstrate that ascorbic
acid is necessary for a normal course of cholesterol catabolism. In latent vitamin C deficiency, the rate of cholesterol catabolism
slows down and cholesterol consequently accumulates in the blood and liver of vitamin C-deficient guinea pigs. 相似文献
15.
The effect of phosphatidylserine and sterol carrier proteins on cholesterol exchange was determined using an assay not requiring
separation of donor and acceptor membrane vesicles. Sterol carrier protein-2 (SCP2, also called nonspecific lipid transfer protein), but not fatty acid binding protein (FABP, also called sterol carrier protein),
enhanced the initial rate of sterol exchange between neutral zwitterionic phosphatidylcholine small unilamellar vesicles (SUV)
2.3-fold. Phosphatidylserine at 10 mol% increased the initial rate of spontaneous and of SCP2-mediated (but not FABP-mediated) sterol exchange by 22% and 44-fold, respectively. The SCP2 potentiation of sterol transfer was dependent on SCP2 concentration and on phosphatidylserine concentration. The SCP2-mediated sterol transfer was inhibited by a variety of cations including KCl, divalent metal ions, and neomycin. The data
suggest that SCP2 increase in activity for sterol transfer may be partly ascribed to charge on the phospholipid.
A portion of this work was presented as an abstract: Nemecz, G., Butko, P., and Schroeder, f. (1989)Biophysical Journal 55, 137a. 相似文献
16.
Free and esterified sterol fractions were isolated fromAspergillus oryzae, and their components analyzed mainly by gas chromatography-mass spectrometry. Cholesterol, brassicasterol, episterol (5α-ergosta-7,24[28]-dien-3β-ol),
4α-methyl-5α-ergosta-8[9],24[28]-dien-3β-ol, lanosterol and 24-methylene-24-dihydrolanosterol were well characterized, whereas
5-dihydroergosterol, sitosterol and 24[28]-dehydroergosterol were tentatively characterized. The principal sterol of the free
sterol fraction was brassicasterol, and that of the esterified sterol fraction was episterol. Ergosterol, which is reported
to be widely distributed in the fungi kingdom, was not detected. 相似文献
17.
Flaxseed and sesame seed both contain more than 40% fat, about 20% protein, and vitamin E, mostly γ-tocopherol. Furthermore,
both contain considerable amounts of plant lignans. However, flaxseed contains 54% α-linolenic acid, but sesame seed only
0.6%, and the chemical structures of flaxseed and sesame lignans are different. In this study, we investigated the differential
effects of flaxseed and sesame seed on plasma and tissue γ-tocopherol, TBARS, and cholesterol concentrations. Rats were fed
experimental diets for 4 wk: vitamin E-free, (-VE), γ-tocopherol, flaxseed (FS), sesame seed (SS), flaxseed oil (FO), FO with
sesamin (FOS), and defatted flaxseed (DFF). SS and FOS diets induced significantly higher γ-tocopherol concentrations in plasma
and liver compared with FS, FO, and DFF diets. Groups fed FS, FO, and FOS showed lower plasma total cholesterol compared with
the SS and DFF groups. Higher TBARS concentrations in plasma and liver were observed in the FS and FO groups but not in the
FOS groups. These results suggest that sesame seed and its lignans induced higher γ-tocopherol and lower TBARS concentrations,
whereas flaxseed lignans had no such effects. Further, α-linolenic acid produced strong plasma cholesterol-lowering effects
and higher TBARS concentrations. 相似文献
18.
The properties and fatty acid and sterol specificity of cholesterol-esterifying enzyme (EC 3.1.1.13) in rat brain were studied.
The enzyme utilized free fatty acid for esterification, and activity was maximal at pH 5.6. Exogenous ATP and CoA did not
stimulate the incorporation of free fatty acids into sterol esters. Substrates dispersed in Tween 20 or Triton X-100 were
just as effective as the substrates dissolved in acetone solution, while dispersion in propylene glycol or sodium taurocholate
was not as effective. Snake venom phospholipase A2 (EC 3.1.1.4) increased the esterification of cholesterol in the absence of added fatty acid. The fatty acid specificity data
indicated that oleic and palmitic acids were the preferred fatty acids. Little or no esterification occurred in the presence
of long chain fatty acids (C20–C24). Esterification of cholesterol with palmitate or stearate was not affected by the presence of oleic acid in the mixture.
Thus, the nonrequirement of the brain-esterifying enzyme for a bile acid or for an amphiphile such as an unsaturated fatty
acid suggests that micellar solubilization of the substrate is not essential for activity. Although the brain enzyme catalyzed
the esterification of desmosterol, cholesterol was the preferred substrate. Neither lanosterol (C29 sterols) nor Δ7-dehydrocholesterol was esterified to any significant extent. The presence of low concentrations of desmosterol
increased cholesterol esterification slightly, while there was a concentration-dependent inhibition of demosterol esterification
by cholesterol. These data on fatty acid and sterol specificity of the esterifying enzyme correlate well with the composition
of sterol esters present in developing rat brain. 相似文献
19.
Weihua Ni Susumu Yoshida Yasuyuki Tsuda Koji Nagao Masao Sato Katsumi Imaizumi 《Lipids》1999,34(7):713-716
Soy protein preparations were reported to have hypocholesterolemic actions in experimental animals and humans, while the active
components and the mechanism by which this occurs are not clarified yet. The objective of this study is to address these issues
by using exogenously hypercholesterolemic rats which are susceptible to dietary cholesterol. Two groups of five rats (male,
12-wk-old) were fed on AIN 93G-based diet with soy protein isolate (SPI) or ethanol-extracted SPI (EE-SPI) for 2 wk. EE-SPI
was prepared by ethanol extraction to remove isoflavones and other components. Concentrations of serum and liver total cholesterol
were lower in rats fed SPI than in those fed EE-SPI. The abundances of mRNA for 7α-hydroxylase and low density lipoprotein
receptor in the liver were lower in EE-SPI group than those in SPI group. These results suggest that the ethanol extract from
SPI has a factor(s) to alleviate hypercholesterolemia by increasing the removal of cholesterol from serum through the receptor
pathway and then from liver through enhancement of bile acid synthesis. 相似文献
20.
In this communication we attempt to provide one possible explanation for the observed differences regarding kinetics and distribution
between simvastatin and pravastatin. Rats treated with simvastatin or pravastatin exhibited a reduction in the incorporation
of [2-14C]acetate into liver cholesterol and displayed lower plasma mevalonate levels as compared to control animals. Moreover, both
the total and dephosphorylated 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase (EC 1.1.1.34) activities, particularly 1
h after treatment, were greatly reduced in liver microsomes obtained from simvastatin-treated as compared to control rats.
During the same time frame, these parameters were actually elevated with pravastatin treatment. It is known that HMG-CoA reductase
synthesis and activity increase following their competitive inhibition. Our results suggest that pravastatin, at 1 h following
treatment, was no longer bound to the enzyme; however, it had entered the liver because its inhibitory effect on cholesterol
synthesis was manifest at early times after administration. These data provide a plausible rationale for the earlier observation
that activity of simvastatin persists longer in plasma than does that of pravastatin. 相似文献