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1.
Bengt E. Gustafsson Bo Angelin Ingemar Björkhem Kurt Einarsson Jan-Åke Gustafsson 《Lipids》1981,16(4):228-233
The aim of this investigation was to study the influence of chenodeoxycholic acid administration on cholesterol and bile acid
synthesis in germ-free rats. Seven rats were fed a basal diet and 2 groups of 4 rats received the same diet supplemented with
0.4 and 1% chenodeoxycholic acid, respectively. After 6 weeks, feces were collected in one 3- and one 4-day pool for analysis
of cholesterol and bile acids. When the sampling period was finished, the rats were killed and the liver microsomal fractions
isolated. The activities of HMG CoA reductase and cholesterol 7α-hydroxylase were determined, the 7α-hydroxylase by a mass
fragmentographic method. The 2 dominating bile acids in the untreated rats were cholic acid and β-muricholic acid. During
treatment with chenodeoxycholic acid, 60–70% of this bile acid was converted into α- and β-muricholic acid, indicating a high
activity of the 6β-hydroxylase. The excretion of cholic acid was almost completely inhibited and the 7α-hydroxylase activity
was decreased ca 75% in the rats fed 1% chenodeoxycholic acid. The activity of the hepatic HMG CoA reductase was unchanged.
The fecal excretion of cholesterol increased 2–3 times. An accumulation of cholesterol was seen in the rats treated with 1%
chenodeoxycholic acid, which was probably a result of the decreased catabolism of cholesterol to bile acids. 相似文献
2.
Feeding a diet high in excess histidine (5% L-histidine) resulted in hypercholesterolemia and enlargement of the liver in
rats. To clarify the mechanism of the hypercho-lesterolemia cholesterol synthesis and degradation were followed. We found
that hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity in histidine-excess diet rats was significantly higher
than in rats fed a basal diet. Incorporation of [3H]water into cholesterol of liver slices from rats fed the histidine-excess diet was higher than incorporation into liver
slices from rats fed the basal diet (expressed per liver per 100 g body weight).In vivo incorporation of [3H]water into hepatic cholesterol was also higher, but the incorporation into cholesterol of the small intestine was lower
in histidine-fed rats than in rats fed the basal diet (expressed per liver per 100 g body weight). Hepatic cholesterol 7α-hydroxylase
activity was similar in both groups. The data suggest that the hypercholester-olemia caused by histidine-excess diet appears
to be due to the stimulation of cholesterol synthesis in the liver. 相似文献
3.
We investigated the influence of an egg-enriched diet on plasma, hepatic and fecal lipid levels and on gene expression levels
of transporters, receptors and enzymes involved in cholesterol metabolism. Sprague–Dawley rats fed an egg-enriched diet had
lower plasma triglycerides, total cholesterol, low density lipoprotein (LDL)-cholesterol, hepatic triglyceride, and cholesterol
concentrations, and greater plasma high-density lipoprotein cholesterol concentration, fecal neutral sterol and bile acid
concentrations than those fed a plain cholesterol diet. Chicken egg yolk had no effect on sterol 12α-hydroxylase and sterol
27α-hydroxylase; but upregulated mRNA levels of hepatic LDL-receptor, cholesterol 7α-hydroxylase (CYP7A1) and lecithin cholesterol
acyltransferase, and downregulated hepatic hydroxymethylglutaryl-(HMG)-CoA reductase and acyl-CoA:cholesterol acyltransferase
(ACAT) after 90 days. Modification of the lipoprotein profile by an egg-enriched diet was mediated by reducing de novo cholesterol
synthesis and enhancing the excretion of fecal cholesterol, via upregulation of CYP7A1 and the LDL receptor, and downregulation
of HMG-CoA reductase and ACAT. 相似文献
4.
The effects of amino acid-fortified low casein and fish oil (FO) diets on hyperlipidemia and proteinuria were studied in rats
with nephrotoxic serum nephritis. After an antiserum injection, rats were maintained for 14 d on four different experimental
diets: a 20% casein diet containing corn oil (CO) or FO, or an 8% casein diet supplemented with cystine plus threonine containing
CO or FO. The 8% casein diets reduced urinary protein excretion in nephritic rats without inducing severe growth retardation
or fatty liver compared with the basal 20% casein diets. Both the 8% casein diet and the FO diet decreased serum cholesterol,
triglyceride and phospholipid levels in nephritic rats, and nonesterified fatty acid levels were decreased by FO feeding.
In nephritic animals, hepatic cholesterol synthesis was decreased by the 8% casein diets compared with the 20% casein diets,
and tended to be reduced by FO feeding between groups at the same casein levels. No effect of diet was observed on fatty acid
synthesis among the nephritic rats. FO administration to the nephritic animals suppressed fecal steroid excretion. While lipoprotein
lipase activity was unchanged among the nephritic rats, hepatic triglyceride lipase activity was reduced by either the 8%
casein or FO diet. The results suggest that the hypolipidemic action of low casein diets may, at least in part, be due to
reduced hepatic cholesterol synthesis and suppressed triglyceride secretion from the liver. They also suggest that the hypolipidemic
action of FO may, at least in part, be due to reduced hepatic cholesterol synthesis and decreased fatty acid mobilization
from peripheral adipose tissue. 相似文献
5.
The effect of cabbage extract on cholesterol metabolism was studied in Donryu rats subcutaneously implanted with an ascites
hepatoma cell line (AH109A). The hepatoma-bearing rats exhibited hypercholesterolemia induced by increasing cholesterogenesis
in the host liver and decreasing steroid excretion into feces. The cabbage extract intake or administration reduced serum
cholesterol level and enhanced fecal bile acid excretion and cholesterol 7α-hydroxylase activity, the rate-limiting enzyme
of bile acid biosynthesis, in the microsomal fraction of the liver. Furthermore, S-methyl-l-cysteine sulfoxide, a component of cabbage, could mimic the effect of cabbage extract when orally administered. These results
suggest that cabbage suppresses hypercholesterolemia responding to hepatoma growth by upregulating cholesterol catabolism
and that S-methyl-l-cysteine sulfoxide in cabbage is one of the factors suppressing hypercholesterolemia in the hepatoma-bearing rats. 相似文献
6.
Kyoichi Osada Takehiro Kodama Koji Yamada Shingo Nakamura Michihiro Sugano 《Lipids》1998,33(8):757-764
The interactive effect of high dietary levels of oxidized cholesterol on exogenous cholerterol and linoleic acid metabolism
was examined in male 4-wk-old Sprague-Dawley rats given high-cholesterol diets. The rats were pair-fed purified diets free
of or containing either 0.5% cholesterol alone or both 0.5% cholesterol and 0.5% oxidized cholesterol mixture (containing
93% oxidized cholesterol) for 3 wk. Hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity was reduced in rats given cholesterol
alone or both cholesterol and oxidized cholesterol. However, hepatic cholesterol 7α-hydroxylase activity was lowered only
when rats were given both cholesterol and oxidized cholesterol, although dietary cholesterol increased this activity. Reflecting
this effect, acidic steroid excretion was lowest among the groups of rats given cholesterol and oxidized cholesterol. On the
other hand, the activity of hepatic Δ6 desaturase, a key enzyme in the metabolism of linoleic acid to arachidonic acid, was
increased in rats given both cholesterol and oxidized cholesterol, although dietary cholesterol alone lowered its activity.
As a result, the Δ6 desaturation index, 20∶3n-6+20∶4n-6/18∶2n-6, in liver and serum phosphlipids tended to be higher in the
group fed both cholesterol and oxidized cholesterol than in the one fed cholesterol alone. Thus, dietary oxidized cholesterol
significantly modulated exogenous cholesterol metabolism and promoted linoleic acid desaturation even when it was given at
high levels together with a high cholesterol diet. 相似文献
7.
Contrasting effects of water-soluble and water-insoluble dietary fibers on bile acid conjugation and taurine metabolism in the rat 总被引:2,自引:0,他引:2
The effect of the type of dietary fiber on the bile acid and taurine metabolism was examined in rats. Diets containing 10%
of various water-soluble fibers (citrus pectin, konjak mannan, guar gum) as compared to a fiber-free diet increased biliary
excretion of total bile acids. In contrast, water-insoluble dietary fibers (cellulose, corn bran, chitin; 10% in the diets)
as well as cholestyramine (5% in the diet) considerably, decreased bile acid excretion. Water-soluble dietary fibermediated
increases in bile acid excretion were totally attributable to increases in glycine-conjugates. Thus, these fibers greatly
increased by the bile acid glycine-to-taurine ratio (G/T). Excretio of glycine conjugates decreased more than that of taurine
conjugates in rats fed various water-insoluble dietary fibers. As a results, G/T in rats fed water-insoluble fibers was significantly
lowered as compared to G/T in animals fed a fiber-free diet. Cholestyramine did not affect the G/T ratio of bile acids. Fecal
bile acid excretion and the activities of hepatic cholesterol 7α-hydroxylase (EC 1.14.13.17) in rats fed various water-soluble
dietary fibers approximately doubled as compared to the respective values for rats fed a fiber-free diet. Whereas cholestyramine
greatly increased these parameters, water-insoluble fibers did not significantly affect them. Various water-soluble fibers
decreased hepatic concentration and urinary excretion of taurine as well as the activity of hepatic cysteine dioxygenase (EC
1.13.11.20). In contrast, water-insoluble fibers considerably increased hepatic taurine concentrations and enzyme activities.
The parameters for taurine metabolism were unaffected by cholestyramine. It was suggested that the types of dietary fiber
affected hepatic taurine synthesis and thus modified bile acid glycine/taurine ratios. 相似文献
8.
Marie-Laure Favier Pierre-Etienne Bost Christine Guittard Christian Demigné Christian Rémésy 《Lipids》1997,32(9):953-959
The effects of partially hydrolyzed, nonviscous, guar gum (PHGG) on cholesterol metabolism and digestive balance have been
compared with those of native guar gum (GUAR) in rats adapted to 0.4% cholesterol diets. Both types of guar gum elicited acidic
fermentations in the large intestine, but only GUAR effectively lowered plasma cholesterol (P<0.001), chiefly in the triglyceride-rich lipoprotein fraction. The biliary bile acid excretion was significantly enhanced
in rats fed GUAR (P<0.05), as well as the intestinal and cecal bile acid pool (P<0.001). In rats fed GUAR and to a lesser extent in those fed PHGG, the fecal excretion of bile acids and neutral sterol was
higher than in controls (P<0.01). The digestive balance (cholesterol intake-steroid excretion) was positive in control rats (+47 μmol/d), whereas it
was negative in rats fed GUAR (−20 μmol/d), which could involve a higher rate of endogenous cholesterol synthesis. In rats
fed PHGG, the steroid balance remained slightly positive. Liver 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity
was very low (22 pmol/min/mg protein), owing to cholesterol supplementation, in control rats or in rats fed PHGG, whereas
it was markedly higher (+463%) in rats fed GUAR. In conclusion, even if PHGG does alter some parameters of the enterohepatic
cycle of cholesterol and bile acids, its effects are not sufficient to elicit a significant cholesterol-lowering effect. The
intestinal (ileal or cecal) reabsorption of bile acids was not reduced, but rather increased, by GUAR; nevertheless the intestinal
capacities of reabsorption were overwhelmed by the enlargement of the digestive pool of bile acids. In the present model,
induction of HMG-CoA reductase probably takes place in the presence of elevated portal bile acid concentrations. 相似文献
9.
Marie-Laure Favier Pierre-Etienne Bost Christian Demigné Christian Rémésy 《Lipids》1998,33(8):765-771
A viscous hydrocolloid (guar gum, GG; 2.5% of the diet) or a steroid sequestrant (cholestyramine; 0.5% of the diet) was included
in semipurified diets containing 0.2% cholesterol to compare the cholesterol-lowering effects of each agent in rats. In the
present model, GG significantly lowered plasma cholesterol (−25%), especially in the density <1.040 kg/L fraction, whereas
cholestyramine was less potent. Bile acid fecal excretion significantly increased only in rats fed cholestyramine, similar
to the cecal bile acid pool; the biliary bile acid secretion was accelerated by GG, but not their fecal excretion, whereas
GG effectively enhanced neutral sterol excretion. As a result, the total steroid balance (+13 μmol/d in the control) was shifted
toward negative values in rats fed the GG or cholestyramine diets (−27 or −50 μmol/d, respectively). Both agents induced liver
3-hydroxy-3-methylglutaryl-CoA reductase, but cholestyramine was more potent than GG in this respect. The present data suggest
that, at a relative low dose in the diet, GG may be more effective than cholestyramine in lowering plasma cholesterol by impairing
cholesterol absorption and by accelerating the small intestine/liver cycling of bile acids, which is interestingly, accompanied
by reduction of bile acid concentration in the large intestine. 相似文献
10.
The effect of a hypercholesterolemic diet (HCD) on hyperlipemia and atherogenesis was investigated using normotensive Wistar/Kyoto
rats (WKY), spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP), with systolic blood pressures increasing in
that order. Feeding an HCD diet containing cholesterol, cholate and suet induced hypercholesterolemia in all the strains examined
as compared with a normal diet. The plasma cholesterol levels were significantly higher in WKY than in SHR and SHRSP fed the
HCD diet. The HCD diet also induced hepatic fat deposition, particularly deposition of cholesteryl esters, a slight increase
in aortic cholesterol deposition, and elevation of both monoenoic/saturated fatty acid ratios and linoleate/arachidonate ratios
in tissue lipids. The changes induced in the three strains by the HCD diet were not positively correlated with blood pressures.
The HCD diet affected hepatic acyl-CoA:cholesterol acyltransferase and plasma lecithin:cholesterol acyltransferase activities
differently in WKY and SHR which, in addition to the induction of Δ9 desaturase, may partly account for the difference in
the diet-induced changes in the fatty acid compositions of plasma cholesteryl esters. The results indicate that hypertensionper se does not stimulate the development of hypercholesterolemia and arterial cholesterol deposition induced by an HCD diet, suggesting
that other factors are involved. 相似文献
11.
Yasuharu Imai Sumio Kawata Masami Inada Shio Miyoshi Yuzo Minami Yuji Matsuzawa Kiyohisa Uchida Seiichiro Tarui 《Lipids》1987,22(7):513-516
Effects of cholestyramine on biliary secretion of cholesterol, phospholipids and bile acids and fecal excretion of sterols
and bile acids were examined in Wistar male rats. Six rats were fed a basal diet, and the other six were fed a basal diet
supplemented with 5% cholestyramine for eight days. Bile flow and biliary secretion of bile acids and phospholipids (per hour
per rat) decreased with cholestyramine treatment, while biliary cholesterol secretion (per hour per rat) remained unchanged.
In the biliary bile acid composition, a marked increase of chenodeoxycholic acid with a concomitant decrease of β-muricholic
acid was observed in cholestyramine-treated rats. Fecal excretion of total sterols and bile acids increased about three-and
four-fold, respectively, after cholestyramine treatment. The increase of fecal bile acids derived from cholic acid was more
predominant than that derived from chenodeoxylcholic acid, resulting in an increase of the cholic acid group/chenodeoxycholic
acid group ratio. 相似文献
12.
Udagawa H Kitaoka C Sakamoto T Kobayashi-Hattori K Oishi Y Arai S Takita T 《Lipids》2008,43(8):695-702
The effects of four cornstarches containing various contents of resistant starch on serum and liver cholesterol levels in rats fed a high-cholesterol diet were investigated. Male Sprague Dawley rats (aged 4 weeks) were divided into four groups (n = 7) and fed high-cholesterol diets containing 15% of cornstarch (CS), heat-moisture-treated CS (HCS), high-amylose CS (HA), or heat-moisture-treated HA (HHA) for 21 days. The results showed that the serum and hepatic level of total cholesterol, LDL-cholesterol, and triglyceride in rats of the HHA group and their arteriosclerosis index were significantly higher, suggesting that HHA increases the risk of arteriosclerosis under a high-cholesterol dietary condition. No significant between-group differences were noted in the levels of plasma mevalonic acid and hepatic HMG-CoA reductase mRNA, whereas fecal cholesterol excretion was significantly higher in the HHA group, indicating that the elevation of the serum and liver cholesterol levels was not due to the promotion of liver cholesterol synthesis and cholesterol absorption in the intestine. 相似文献
13.
The effect of chitosan feeding (for 21 days) on intestinal bile acids was studied in male rats. Serum cholesterol levels in
rats fed a commercial diet low in cholesterol were decreased by chitosan supplementation. Chitosan inhibited the transformation
of cholesterol to coprostanol without causing a qualitative change in fecal excretion of these neutral sterols. Increased
fiber consumption did not increase fecal excretion of bile acids, but caused a marked change in fecal bile acid composition.
Litcholic acid increased sigificantly, deoxycholic acid increased to a leasser extent, whereas hyodeoxycholic acid and the
6β-isomer and 5-epimeric 3α-hydroxy-6-keto-cholanoic acid(s) decreased. The pH in the cecum and colon became elevated by chitosan
feeding which affected the conversion of primary bile acids to secondary bile acids in the large intestine. In the cecum,
chitosan feeding increased the concentration of α-,β-, and ω-muricholic acids, and lithocholic acid. However, the levels of
hyodeoxycholic acid and its 6β-isomer, of monohydroxy-monoketo-cholanoic acids, and of 3α, 6ξ, 7ξ-trihydroxy-cholanoic acid
decreased. The data suggest that chitosan feeding affects the metabolism of intestinal bile acids in rats. 相似文献
14.
Hypercholesterolemic rats, fed 1% cholesterol and 0.5% glycocholate, were treated with arylsulfonates in various ways to observe
the pattern of cholesterol elimination. Dietary linoleyl p-toluene-sulfonate (LTS) hastened return to normocholesterolemia
and lowered hepatic cholesterol either with or without continued cholesterol feeding. LTS administered via the portal vein
significantly lowered plasma cholesterol in 48 hr; ethyl linoleate and monoolein produced no lowering. LTS administered via
the portal vein to glycocholate-infused rats increased the biliary excretions of label from [4-14C]cholesterol administered intracardially and also increased total bile acid excretion 21% without increased bile volume when
compared to similar injection of ethyl linoleate. No change in biliary excretion of cholesterol was seen. Bile acid kinetics
were studied by using isotopic dilution techniques. Cholate turnover was enhanced by feeding oleyl p-toluenesulfonate (OTS)
and oleylp-(n-decyl)-benzenesulfonate (ODS) as suggested by a 16–35% decrease in half-life in both normal and hypercholesterolemic rats.
Rats consuming a grain-based colony diet had a 54% increase in cholate synthesis when OTS was included in the diet. The composition
of bile was changed when either OTS or ODS was fed; an increase in chenodeoxycholate was noted. This change was gradual with
OTS but rapid with ODS and paralleled enhanced decay of chenodeoxycholate specific radioactivity in response to treatment.
ODS and OTS also increased14CO2 expiration from oral [26-14C] cholesterol in hypercholesterolemic rats. Dietary OTS and ODS elevated hepatic free cholesterol in hypercholesterolemic
rats; ODS also elevated plasma free cholesterol and increased cholesteryl ester hydrolase activity in the liver. The data
suggest that arylsulfonates stimulate cholesterol catabolism, in addition to the reported inhibition of cholesterol absorption
[Lipids 12:819 (1977)].
Published as Journal Paper No. 6699, A.E.S., Purdue University. 相似文献
15.
Cholesterol biosynthesis from acetate-2-14C by the livers of suckling rats, which is known to be relatively slow, was increased 2–3-fold within 24 hours after severing
the bile duct. Cholesterol synthesis by sham-operated litter mates showed no change under similar treatment. Mevalonate biosynthesis
from acetate-2-14C in vitro by recombined liver microsomal supernatant (105,000×g) fractions from suckling rats also was only 10% of that of
comparable recombined fractions from normal controls (young adult rats which were consuming colony diet). Activity was not
improved by combining either the microsomal or supernatant fraction from suckling rat livers with the complementary fraction
from normal adult livers. On the other hand, activity was restored to 100% when microsomes from livers of duct-served suckling
rats were combined with the supernatant fraction from normal controls. Likewise, recombined liver fractions prepared from
adult rats fed synthetic diets exhibited low activity for mevalonate biosynthesis. Activity was restored by bile duct cannulation,
but inhibited when cholic acid was infused into the cannulated animal. Therefore, surgical procedures which interrupt the
enterohepatic recirculation of bile components lead to a restoration of cholesterol biosynthesis and, at least in the adult
animal where cannulation studies are practicable, this effect can be reversed readily by bile acid infusion.
A slow rate of fecal excretion of14C-cholic acid was observed in suckling rats and rats fed synthetic diets, apparently reflecting an efficient enterohepatic
recirculation of bile salts. The data suggest that under these dietary conditions bile salt retention either directly or indirectly
influences hepatic synthesis of cholesterol.
Presented in part before Federation of American Societies for Experimental Biology, Fed. Proc.24, 1078, 1965 (abstract). and in part at the AOCS Meeting, Los Angeles, April 1966.
Journal Paper No.2835, Purdue University Agricultural Experiment Station. 相似文献
16.
Masaharu Kamei Sumiko Ohgaki Tamotsu Kanbe Mitsuru Shimizu Shigeru Morita Isao Niiya Isao Matsui-Yuasa Shuzo Otani 《Lipids》1996,31(11):1151-1156
The effects of dietary highly hydrogenated soybean oil (HSO) upon the changes caused by dietary polychlorinated biphenyls
(PCBs) were examined in rats. Six groups of rats were fed the following diets for 30 d: a 20% soybean oil-containing diet
(control diet), a diet in which a half of soybean oil was substituted with HSO (HSO-A diet), a diet in which cellulose powder
was replaced with HSO (HSO-B diet) and these diets supplemented with 100 ppm PCBs (control+PCBs, HSO-A+PCBs and HSO-B+PCBs
diets). Hepatic concentration of PCBs and relative liver weight were markedly decreased in rats fed with the HSO-A+PCBs diet
compared with those fed with the other diets containing PCBs. Liver lipids and liver cholesterol were considerably decreased
with a reciprocal increase in fecal sterol excretion by rats fed the HSO-A+PCBs and the HSO-B+PCBs diets compared with those
fed with the control+PCBs diet. The fatty acid composition in hepatic phospholipids showed an independent increase of the
saturated fatty acid content induced by dietary HSO and PCBs. Dietary PCBs also caused decreases in the amounts of monounsaturated
and n-3 polyunsaturated fatty acids. These results suggest that dietary HSO prevents accumulation of PCBs in the liver and
promotes the excretion of lipids stimulated by PCBs, accompanied by a change in fatty acid metabolism. 相似文献
17.
Effects of dietary methionine and cystine on lipid metabolism in hepatoma-bearing rats with hyperlipidemia 总被引:2,自引:0,他引:2
Abnormal lipid metabolism and its restoration by dietary methionine (Met) and cystine (Cys) were studied in Donryu rats subcutaneously
implanted with an ascites hepatoma cell line of AH109A. The hepatoma-bearing rats exhibited byperlipidemia characterized by
rises in serum triglyceride and cholesterol levels. Decreased lipoprotein lipase (LPL) activities in epididymal adipose tissue,
cardiac muscle, and gastrocnemius as well as increased fatty acid mobilization from adipose tissue were considered to be responsible
for the hepatoma-induced hypertriglyceridemia, while increased hepatic cholesterogenesis and decreased steroid excretion into
feces were thought to be responsible for the hepatoma-induced hypercholesterolemia. Dietary-supplemented Met or Cys reduced
the AH109A-induced hypertriglyceridemia with suppression of fatty acid synthesis in the host liver. Met restored the fall
of LPL activities, while Cys did not. Dietary Met or Cys also reduced the hypercholesterolemia with restoration of decreased
bile acid excretion into feces. These results suggest that dietary Met or Cys is hypolipidemic in the hepatoma-bearing rats
with slight differences in their modes of action. 相似文献
18.
Feeding rats beans with resistant starch reduces their serum cholesterol concentration; however, the mechanism by which this
occurs is not fully understood. We examined the effects of enzyme-resistant fractions of adzuki (Vigna angularis) and tebou (Phaseolus vulgaris, var.) beans on serum cholesterol and hepatic mRNA in rats. Rats were fed a cholesterol-free diet with 50 g of cellulose
powder (CP)/kg, 50 g of an enzyme-resistant fraction of adzuki starch (AS)/kg, or 50 g of an enzyme-resistant fraction of
tebou starch (TS)/kg diet for 4 wk. There were no significant differences in body weight, liver weight, and cecum contents
among the groups, nor was there a significant difference in food intake among the groups. The levels of serum total cholesterol,
VLDL + intermediate density lipoprotein + LDL-cholesterol, and HDL cholesterol in the AS and TS groups were significantly
(P<0.05) lower than in the CP group throughout the feeding period. Total hepatic cholesterol in the CP group was significantly
(P<0.05) lower than in the AS and TS groups, fecal cholesterol excretion in the TS group was significantly (P<0.05) greater than in the CP and AS groups, and the fecal total bile acid concentrations in the AS and TS groups were significantly
(P<0.05) higher than in the CP group. Cecal acetate, propionate, and n-butyrate concentrations in the AS and TS groups were significantly (P<0.05) higher than in the CP group. The level of hepatic scavenger receptor class B1 (SR-B1) mRNA in the TS group was significantly
(P<0.05) higher than in the CP group, and the levels of hepatic cholesterol 7α-hydroxylase mRNA in the AS and TS groups were
significantly (P<0.05) higher than in the CP group. These results suggest that AS and TS have a serum cholesterol-lowering function due to
the enhanced levels of hepatic SR-B1 and cholesterol 7α-hydroxylase mRNA. 相似文献
19.
Effectiveness of resistant starch,compared to guar gum,in depressing plasma cholesterol and enhancing fecal steroid excretion 总被引:2,自引:0,他引:2
Marie-Anne Levrat Corinne Moundras Hassan Younes Christine Morand Christian Demigné Christian Rémésy 《Lipids》1996,31(10):1069-1075
Amylase-resistant starch (RS) represents a substrate that can be administered in substantial amounts in the diet, in contrast
to gel-forming polysaccharides, such as guar gum (GG). The aim of this work was thus to compare the effects of GG and RS on
cholesterol metabolism in rats adapted to 0.4% cholesterol diets, using dietary GG or RS levels (8 or 20%, respectively) that
led to a similar development of fermentations, as assessed by the degree of enlargement of the cecum. The RS diet elicited
a marked rise in the cecal pool of short-chain fatty acids, especially acetic and butyric acid, whereas the GG diet favored
high-propionic acid fermentations. Both polysaccharides markedly altered the cholesterol excretion, from 50% of ingested cholesterol
in controls, up to about 70% in rats adapted to the RS or GG diets. With these diets, the fecal excretion of bile acids was
enhanced (67 and 144% with the RS and GG diets, respectively). RS and GG diets were effective in lowering plasma cholesterol
(about −40%) and triglycerides (−36%). There was practically no effect of the diets on cholesterol in d>1.040 lipoproteins
(high density lipoproteins), whereas RS (and to a larger extent, GG) were very effective to depress cholesterol in d<1.040
lipoproteins (especially in triglyceride-rich lipoproteins). Fermentable polysaccharides counteracted the accumulation of
cholesterol in the liver, especially cholesterol esters. In parallel, liver acyl CoA:cholesterol acyltransferase was depressed
in rats fed the RS or GG diets, whereas only the GG diet counteracted the downregulation of 3-hydroxy-3-methylglutaryl-CoA
by cholesterol. These data suggest that RS may be practically as effective as a gel-forming gum, such as GG, on steroid excretion
and on cholesterol metabolism. 相似文献
20.
Mechanisms Underlying Decreased Hepatic Triacylglycerol and Cholesterol by Dietary Bitter Melon Extract in the Rat 总被引:4,自引:0,他引:4
Senanayake GV Fukuda N Nshizono S Wang YM Nagao K Yanagita T Iwamoto M Ohta H 《Lipids》2012,47(5):495-503
In these studies, we focused on finding the mechanism(s) underlying the bitter melon (Momordica charantia L.) methanol fraction (MF)-dependent reduction in the concentration of hepatic triacylglycerol (TAG) and cholesterol in the
rat. Rats were fed diets containing low (5 %) fat for 2 weeks (experiment 1), or low (5 %) and high (15 %) fat for a longer
period of 8 weeks (experiment 2). MF was supplemented at 1 % level in both experiments. After feeding, rats were sacrificed,
and their livers were prepared as slices and hepatocytes, followed by incubation with [1(2)-14C] acetate or [1-14C] oleic acid (18:1 n-6). Under these conditions, we found that rats fed diets containing MF, as compared to those without
MF, showed: (1) no adverse effects on food intake and growth, (2) a decreased hepatic TAG and total cholesterol, irrespective
of the difference in dietary fat level or feeding period, and (3) a decreased incorporation of [1(2)-14C] acetate and [1-14C] oleic acid into TAG of liver slices and hepatocytes. MF-supplemented rats also showed no altered incorporation of labeled
acetate into cholesterol and cholesterol ester, an increased fecal excretion of neutral steroids, but not of acidic steroids,
and an enhanced mRNA abundance of carnitine palmitoylacyltransferase I, which is the rate-limiting enzyme for fatty acid oxidation.
These results suggest that dietary MF decreases hepatic TAG synthesis while enhancing fatty acid oxidation, thereby reducing
the concentration of hepatic TAG. The liver cholesterol-lowering effect of MF, however, is probably mediated through an increased
fecal excretion of neutral steroids, without an effect on cholesterogenesis. 相似文献