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1.
André Grandgirard Jean-Pierre Sergiel Mohammed Nour Joelle Demaison-Meloche Christian Gihiès 《Lipids》1999,34(6):563-570
Two of the main classes of oxyphytosterols (7-keto and epoxides) were synthesized from sitosterol and campesterol and given to mesenteric duct-cannulated adult male rats. Lymph was collected during 24 h and was analyzed for oxysterols. The results showed that the lymphatic recovery of the phytosterol oxides was low: 4.7% of the given dose for epoxy derivatives and 1.5% for 7-keto compounds. The campesterol oxides presented a better absorption than the sitosterol oxides. During the process of absorption’ the epoxyphytostanols were also partly transformed in campestanetriol and stigmastanetriol. 相似文献
2.
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
3.
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
4.
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
5.
In this study we determined in rats the complete 24-h lymphatic fatty acid profile after administration of either rapeseed
oil (RO) or rapeseed oil interesterified with 10∶0 (RO/C10) with special emphasis on the transition from absorptive to postabsorptive phase. Rats were subjected to cannulation of the
main mesenteric lymph duct and the next day oils were administered through a gastric feeding tube. Lymph was collected in
1-h fractions for the following 24 h. The time for maximum lymphatic transport of fatty acids was at 4 h with fast changes
in fatty acid composition from the fatty acids of endogenous origin to those of the administered oils. Seven to eight hours
after administration the transport was significantly lower than maximum, indicating the change from absorptive to postabsorptive
phase. At 24 h after administration of either oil the transport of total fatty acids, palmitic acid (16∶0), and linoleic acid
(18∶2n−6) together with oleic acid (18∶1n−9) after RO had not returned to the transport at baseline. In contrast, the transport
of decanoic acid (10∶0) and α-linolenic acid (18∶3n−3) returned to baseline values between 12 and 15 h. This indicated that
the absorption of purely exogenous fatty acids (illustrated by 10∶0 and 18∶3n−3) was complete at 15 h and that the fatty acids
transported between 15 and 24 h were derived mostly from endogenous stores. 相似文献
6.
This experiment was designed to evaluate the effect of casein or ovomucin (OV) on the micellar solubility of cholesterol and
the taurocholate binding capacity in vitro. We also evaluated the effects of casein or OV on cholesterol metabolism in rats and Caco-2 cells. OV has a significantly
greater bile acid-binding capacity than that of casein in vitro. Micellar cholesterol solubility in vitro was significantly lower in the presence of OV compared to casein. The cholesterol micelles containing OV significantly suppressed
cholesterol uptake by Caco-2 cells compared to the cholesterol micelles containing casein. Consistent with these in vitro findings, OV-feeding significantly increased the fecal excretion of bile acids or cholesterol compared with casein-feeding.
Serum total cholesterol was significantly lower in rats fed OV than in those fed casein. The concentrations of total lipids
in liver were significantly lower in the OV-fed group compared with the casein group. These results suggest that the suppression
of cholesterol absorption by direct interaction between cholesterol mixed micelles and OV in the jejunal epithelia is part
of the mechanism underlying the hypocholesterolemic action of OV. OV may also inhibit the reabsorption of bile acids in the
ileum, thus lowering the serum cholesterol level. 相似文献
7.
8.
Plasma cholesterol and cholesterol absorption were measured in rabbits given either a standard or cholesterol-rich diet which
were fed either ad libitum or reduced to 50% of the control ration. The results confirmed the aggravating effect of dietary
restriction on the plama cholesterol response to cholesterol feeding. Hypercholesterolemia was doubled when cholesterol feeding
was associated with reduced dietary intake. The percentage of cholesterol absorbed increased significantly in cholesterolfed
rabbits on normal caloric ration, while dietary restriction had no effect on this parameter either with the standard or the
cholesterol-rich diet. These data indicate that the mechanisms by which plasma cholesterol increases in response to cholesterol
feeding involve increased cholesterol absorption. Nevertheless the aggravating effect of dietary restriction cannot be attributed
to increased cholesterol absorption. 相似文献
9.
The lymphatic absorption of nonvolatile oxidation products (NVOP) formed during heating of fats was studied. Heated colza
or soybean oils or synthetic triglycerides containing a definite aromatic or alicyclic fatty acid were fed to thoracic duct-cannulated
rats. Tritium-labeled triolein was added to each dietary fat, as an internal standard, in order to calculate the percentage
of lymphatic absorption of the ingested NVOP. Results show that 4% of the total polymeric acids, 53% of the total oxidized
monomeric acids and 96% of the total cyclic monomeric acids were recovered in the lymphatic lipids. Gas liquid and quantitative
thin layer chromatography of these 3 classes indicated that, within a NVOP class, the various constituents did not present
the same absorption rate. The lymphatic absorptions of individual oxidized monomers were between 25 and 93%. Concerning the
polymer fraction, the lymphatic recoveries were 1% (nonpolar dimers), 6.8% (polar dimers) and 12% (polar oligomers). Aromatic
acids were absorbed to a lesser degree (50–60%) than cyclohexenic acids (91–98%). 相似文献
10.
11.
Cholesterol absorption is frequently determined using the plasma dual stable-isotope ratio method (PDSIRM). However, this
method involves intravenous injection of stableisotope-labeled cholesterol with simultaneous oral administration of differently
labeled cholesterol, which results in high study costs and involves additional ethical considerations. The objective of the
present study was to validate a simpler singleisotope method for determining cholesterol absorption against PDSIRM by using
data from two previous studies. Enrichments of carbon-13 (13C) and deuterium in red blood cells were analyzed by using differential isotope ratio MS. The area under the curve of 13C-enrichment in the plasma free-cholesterol pool was found to be significantly correlated with cholesterol absorption measured
by using PDSIRM for study 1 (r=0.85, P<0.0001) and study 2 (r=0.81, P<0.0001). Average 13C-enrichment correlated with the area under the curve of 13C-enrichment in the plasma free cholesterol for both study 1 (r=0.98, P<0.0001) and study 2 (r=1.00, P<0.0001). Study 1 examined the efficacy and mechanisms of unesterified plant sterols and stanols on lipid profiles in hypercholesterolemic
men and women, while study 2 investigated the effects of phytosterol vs. phytostanol esters on plasma lipid levels and cholesterol
kinetics in hyperlipidemic men. Experimental approaches to determine cholesterol absorption were identical between the two
studies. Consequently, in both studies, correlations (r=0.88, P<0.0001 for study 1, and r=0.82, P<0.0001 for study 2) were found between the average 13C-enrichment of plasma free cholesterol and cholesterol absorption measured by PDSIRM. These results suggest that a single-isotope-labeled
cholesterol tracer approach can be used as a reliable noninvasive method to replace PDSIRM for examining changes in cholesterol
absorption. 相似文献
12.
In this study we examined the lymphatic transport in rats of FA after administration of interesterified oils containing CLA, with emphasis on the location of CLA and octanoic acid in the TAG. The oils were produced by enzymatic interesterification. Eight oils with different structures or FA profiles were examined in this study: MCM, CMC, OCO, and COC, where M was expected to be octanoic acid and O oleic acid. In group 1, C was CLA as a mixture of the two CLA isomers c9, t11 or t10, c12, and in group 2, C was mainly the isomer t10, c12. Rats were subjected to cannulation of the mesenteric lymph duct, and the following day they were intragastrically administered one of the oils and lymph samples were collected for 24 h. The lymphatic transport of total FA from 0 to 8 h in group 1 was significantly (P < 0.05) higher for the OCO-1 and the COC-1 oils than for the CMC-1 oil. Similarly, in group 2 the transport was higher for the OCO-2 oil than for the CMC-2 oil. The recovery of both of the CLA isomers examined was similar (50-70%) and independent of the isomer, oil structure, and FA profile, whereas more octanoic acid was recovered from the CMC oils than from the MCM oils. The results indicated that the FA profiles and the position of octanoic acid had only a minor influence on the absorption of CLA. 相似文献
13.
Four groups of young male and female rats were fed a chow diet (0), chow plus 10% corn oil (F), chow plus 1% cholesterol (C),
or chow plus 1% cholesterol plus 10% corn oil (CF) for 1, 2, 4 and 8 days. After 2 dats, male F, C and CF rats exhibited a
shorter anesthesia period (−20 to −30%) when given pentobarbital. By 4 days, male F and C rats had pentobarbital sleeping
times (PB-ST) 20% less than 0 rats. These effects were additive and CF rats had 40% shorter PB-ST. Reduction of PB-ST by cholesterol
and corn oil was similar but slightly less in female rats. Liver lipid content doubled in 4 days in CF rats, and liver cholesterol
was 4 times that of 0 rats. These changes and the increases in metabolism of barbiturate suggested changes in liver microsomal
enzyme activities. Serum glutamic oxaloacetic and glutamic pyruvic transaminase, two enzymes reflective of liver damage, did
not increase after 8 days on C, F or CF diets. Our results suggest that consumption of an animal sterol and a high lipid diet
by laboratory rats, normally consuming a diet low in fat (3–4%), increases the ability of the animal to detoxify a barbiturate.
Storage of absorbed dietary cholesterol in the liver may represent a major mechanism for maintaining extra hepatic cholesterol
homeostasis. 相似文献
14.
Lymphatic transport of a mixture of medium-chain TAG (MCT) and long-chain TAG (LCT) was studied in lymph-cannulated rats.
Animals were administered a test emulsion containing either triolein, tricaprylin, or a 1∶1 mixture of triolein and tricaprylin,
and the lymph was collected for 24 h. The lymphatic recovery rate of medium-chain FA (MCFA) was significantly higher in rats
given the TAG mixture than in those given MCT alone. The lymphatic recovery rate of long-chain FA (LCFA) also was significantly
higher in rats given the TAG mixture than in those given LCT alone. No TAG containing three MCFA (i.e., MCT) was detected,
and 37.7% of TAG containing one or two MCFA was detected in the lymph TAG when rats were given the TAG mixture. These results
indicate that lymphatic transport of MCFA and LCFA can be modified by the combination of MCT and LCT. 相似文献
15.
16.
The effect of (−)N-[α-phenyl-β-(p-tolyl)ethyl] linoleamide (PTLA) on intestinal absorption of cholesterol was studied in rats.
Oral administration of 15 mg PTLA to rats resulted in a significant (P<0.05) decrease in the radioactivity in serum and liver
4 hr after administration of labeled cholesterol. The effect of PTLA was greater on the absorption of cholesteryl oleate as
compared with free cholesterol. The rate of hydrolysis of cholesteryl oleate in mucosal homogenates of rat intestine was decreased
with PTLA, suggesting that the inhibition of cholesterol absorption by PTLA is related to its effect on cholesteryl ester
hydrolysis in the intestine. 相似文献
17.
Oryzanol is a class of nonsaponifiable lipids of rice bran oil (RBO). More specifically, oryzanol is a group of ferulic acid
esters of triterpene alcohol and plant sterols. In experiment 1, the mechanisms of the cholesterol-lowering action of oryzanol
were investigated in 32 hamsters made hypercholesterolemic by feeding chow-based diets containing 5% coconut oil and 0.1%
cholesterol with or without 1% oryzanol for 7 wk. Relative to the control animals, oryzanol treatment resulted in a significant
reduction in plasma total cholesterol (TC) (28%, P<0.01) and the sum of IDL-C, LDL-C, and VLDL-C (NON-HDL-C) (34%, P<0.01). In addition, the oryzanol-treated animals also exhibited a 25% reduction in percent cholesterol absorption vs. control
animals. Endogenous cholesterol synthesis, as measured by the liver and intestinal HMG-CoA reductase activities, showed no
difference between the two groups. To determine whether a lower dose of oryzanol was also efficacious and to measure aortic
fatty streaks, 19 hamsters in experiment 2 were divided into two groups and fed for 10 wk chow-based diets containing 0.05%
cholesterol and 10% coconut oil (w/w) (control) and the control diet plus 0.5% oryzanol (oryzanol). Relative to the control,
oryzanol-treated hamsters had reduced plasma TC (44%, P<0.001), NON-HDL-C (57%, P<0.01), and triglyceride (TG) (46%, P<0.05) concentrations. Despite a 12% decrease in high density lipoprotein cholesterol (HDL-C) (P<0.01), the oryzanol-treated animals maintained a more optimum NON-HDL-C/HDL-C profile (1.1±0.4) than the contorl (2.5±1.4;
P<0.0075). Aortic fatty streak formation, so defined by the degree of accumulation of Oil Red O-stained macrophage-derived
foam cells, was reduced 67% (P<0.01) in the oryzanol-treated animals. From these studies, it is concluded that a constituent of the nonsaponifiable lipids
of RBO, oryzanol, is at least partially responsible for the cholesterol-lowering action of RBO. In addition, the cholesterol-lowering
action of oryzanol was associated with significant reductions in aortic fatty streak formation. 相似文献
18.
Randomization of partially hydrogenated corn oil containing approximately 45% oftrans octadecenoic acid only slightly, but not significantly, increased the lymphatic fatty acid absorption in rats. No effect
of randomization was observed on cholesterol absorption. When rats were fed these fats at the 8.8% level (with 1.2% safflower
oil) for three weeks, the concentrations of serum cholesterol, and serum and liver phospholipid were significantly higher
in randomized fat than in control fat, which was composed of 9% high-oleic safflower oil and 1% palm oil. Liver cholesterol
tended to be higher in randomized fat. In contrast, nonrandomized fat was not hyperlipidemic compared to control fat. Although
the fatty acid composition of liver phospholipids suggested a possible interference oftrans fatty acid with the metabolism of linoleic acid to arachidonic acid, there was no effect of randomization. In the two hydrogenated
fat groups,trans octadecenoic acid was incorporated and distributed similarly in adipose tissue triacylglycerol. These observations indicated
that randomization of partially hydrogenated fat is not beneficial to various lipid parameters in rats. 相似文献
19.
20.
Female (Exp. I) or male (Exp. II) weanling rats were fed diets containing either 2% Solka-Floc or 2% agar for 28-day periods.
Some groups received 1% cholesterol, either added in crystalline form or first dispersed in the oil portion of the diet, and
some agar groups received their diet in a gelled form. Feces were collected for a 3-day period after 2 weeks (Exp. II) or
during the fourth week (Exp. I) of experimentation. Serum and liver cholesterol, total liver lipids, fecal lipids, and fecal
sterols were determined. The results indicated that cholesterol feeding increased serum cholesterol, total liver, and fecal
lipids, liver cholesterol, and fecal sterols. Substitution of agar for Solka-Floc in dry (nongelled) diets further increased
total liver lipids (Exp. I), but had no significant effect upon any other measured parameter. Gelling of 1% cholesterol agar
diets, in contrast to the 1% cholesterol dry agar diet, resulted in reduced liver cholesterol in both experiments. Gelling
significantly increased fecal sterols after 2 weeks feeding (Exp. II), but no significant differences were observed after
4 weeks feeding (Exp. I) when compared to 1% cholesterol-fed groups. Small, nonsignificant increases of liver cholesterol
and total liver lipids with similar reduction of fecal sterols resulted from dispersing the cholesterol in the oil portion
of the diet prior to mixing. The results indicate that (a) inclusion of 2% agar in rat diets and (b) dispersing cholesterol
in oil had little effect upon serum, liver, or fecal lipids in cholesterol-fed rats. However, gelling the agar diets reduced
liver cholesterol, possibly by initial reduction of dietary cholesterol absorption. 相似文献