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1.
Triplicate groups of Atlantic salmon (Salmo salar L.) were fed four diets containing different oils as the sole lipid source, i.e., capelin oil, oleic acid-enriched sunflower
oil, a 1∶1 (w/w) mixture of capelin oil and oleic acid-enriched sunflower oil, and palm oil (PO). The β-oxidation capacity,
protein utilization, digestibility of dietary fatty acids and fatty acid composition of lipoproteins, plasma, liver, belly
flap, red and white muscle were measured. Further, the lipid class and protein levels in the lipoproteins were analyzed. The
different dietary fatty acid compositions did not significantly affect protein utilization or β-oxidation capacity in red
muscle. The levels of total cholesterol, triacylglycerols, and protein in very low density lipoprotein (VLDL), low density
lipoprotein (LDL), high density lipoprotein (HDL), and plasma were not significantly affected by the dietary fatty acids.
VLDL, LDL, and HDL fatty acid compositions were decreasingly affected by dietary fatty acid composition. Dietary fatty acid
composition significantly affected both the relative fatty acid composition and the amount of fatty acids (mg fatty acid per
g tissue, wet weight) in belly flap, liver, red and white muscle. Apparent digestibility of the fatty acids measured by adding
yttrium oxide as inert marker, was significantly lower in fish fed the PO diet compared to the other three diets. 相似文献
2.
Native fish-eye disease plasma, which is deficient of both high density lipoproteins (HDL) and lecithin-cholesterol acyltransferase
activity (α-LCAT), processing the free cholesterol of these lipoproteins, has been supplemented with normal isolated HDL2 or HDL3 and incubated in vitro at 37 C. After incubation for 0,7.5 and 24 hr the very low density (VLDL) and low density (LDL) lipoproteins
as well as HDL were isolated, and their contents of triglycerides, phospholipids and free, esterified and total cholesterol
were quantified. The resulting net mass transfer of the different lipids revealed a functioning transfer of cholesteryl esters
and all other analyzed lipids between the lipoproteins, although no de novo esterification of the HDL cholesterol by LCAT
in this plasma occurred. In accordance with previous findings there was a functioning esterification process of the free cholesterol
of the combined VLDL and LDL of fish-eye disease plasma. The present results make it reasonable to conclude that the lack
of HDL cholesterol esterification in this disease is not a result of a deficiency of cholesteryl ester transfer or lipid transfer
activities. 相似文献
3.
Vitamin E has no known plasma carrier protein and is transported by plasma lipoproteins. The site of association of vitamin
E in the lipoprotein particle and the mode of transfer of vitamin E between plasma lipoproteins have not been ascertained.
Since neutral lipids (triglycerides and cholesterol esters) exchange between plasma lipoproteins by processes mediated by
neutral lipid transfer protein, we questioned that if vitamin E, a hydrophobic molecule, is carried in the core of the lipoprotein
particle then its transfer between plasma lipoproteins may be mediated by neutral lipid transfer protein. Transfer of D-α(5-methyl-3H)tocopherol from in vitro-labeled human plasma lipoprotein fractions to other plasma lipoproteins was measured under incubation
conditions that were designed to yield markedly differing degrees of neutral lipid exchange. Despite the presence of the d>1.21
g/ml lipoprotein-poor plasma fraction or purified lipid transfer protein that resulted in up to a 10-fold increase in neutral
lipid transfer, vitamin E transfer between very low density lipoproteins, low density and high density lipoproteins remained
constant. Even excess amounts of lipid transfer protein, which caused triglyceride transfer between very low density and high
density lipoproteins to reach saturation, failed to affect significantly vitamin E transfer. Vitamin E distribution between
lipoprotein fractions did correlate with lipoprotein mass ratios. Vitamin E transfer was higher as the protein ratio of acceptor
lipoproteins to donor lipoproteins increased. We conclude that vitamin E transfer between lipoproteins is not dependent primarily
on neutral lipid transfer protein and is not mediated via neutral lipid transfer. 相似文献
4.
The effect of the liposoluble organophosphorus insecticide fenitrothion (FS) on lipid packing and rotation of two crustacean
plasma HDL was investigated. These lipoproteins, HDL-1 and HDL-2, differed in their lipid composition, but their lipid/protein
ratios were similar. The rotational behavior of the fluorescent probes 1,6-diphenyl-1,3,5-hexatriene (DPH) and 3-(p-(6-phenyl)-1,3,5-hexatrienyl) phenylpropionic acid (DPH-PA) was used to obtain information about the lipid dynamics in the
outer and inner regions, respectively, of the lipid phase of the lipoproteins. Fluorescent steady-state anisotropy (r
s), lifetime (τ), rotational correlation time (τr), and the limiting anisotropy (r
∞) of these probes were measured in the lipoproteins exposed to different concentrations of FS in vitro. The results showed the penetration of FS into both plasma lipoproteins, altering the lipid dynamics of the inner as well
as the outer regions. The overall effect of the insecticide was to induce an increase in the lipid order in a concentration-dependent
fashion. DPH and DPH-PA fluorescence-lifetime shortening indicated that FS increased the polarity of the probe environment,
suggesting an enhanced water penetration into the lipoprotein lipid phase, may be due to the induction of failures in the
lipid packing. Even in the absence of FS, a higher ordering of the lipid phase was found in HDL-2 compared to HDL-1, a fact
that might be attributed to a higher percentage of sphingomyelin in HDL-2.
An erratum to this article is available at . 相似文献
5.
Lipid emulsions (LE) contain triglyceride (TG)-rich particles (TGRP) and phospholipid-rich particles (PLRP). Various lipid
and protein exchanges take place during in vitro incubations of LE with lipoproteins. These composition changes affect physical properties of particles. The aim of this study
was to determine the role of different LE particles and the effect of TG composition on physical modifications. Low density
lipoproteins (LDL: 1.025<d<1.040 g/mL) or high density lipoproteins (HDL: 1.085<d<1.150 g/mL) were incubated with the following four LE or their TGRP or PLRP, which were manufactured with the same phospholipid
emulsifier: long-chain triglycerides (LCT): 100% soybean oil; medium-chain triglycerides (MCT)/LCT (MCT/LCT, 5∶5, w/w); FO
(100% fish oil); and MLF541 (MCT/LCT/FO, 5∶4∶1, by wt). After incubation, modified LE particles and lipoproteins were analyzed
by fluorescence polarization. Observed physical modifications were significant in emulsion particles (ordering effect) but
not in lipoporteins and also were significant for TG composition effect. Since intact emulsion contained a large excess of
TGRP over PLRP, it is not surprising that intact emulsion had the same behavior as TGRP alone, and that PLRP had the same
physical characteristics as lipoproteins. TG loss and cholesterol and protein acquisitions by emulsion particles rigidify
their envelope. The two emulsions containing FO were less ordered after incubation. In conclusion, incubation of LE with lipoproteins
changes physical properties of each kind of particle, and TG composition of the emulsion affects emulsion particle changes
but has no effect on LDL and HDL. These order modifications induce more effective exchanges between LE particles and lipoproteins
and modify their metabolism; HDL changes may increase the reverse cholesterol transport. 相似文献
6.
We compared the effects of three different high-lipid diets on plasma lipoproteins and phospholipids in mink (Mustela vison). The 18 mink studied were fed one of the three diets during a 25-d period in a parallel group design. The compared diets
had 0,17, and 67% extracted lipids from natural gas-utilizing bacteria (LNGB), which were rich in PE. The group with 0% LNGB
was fed a diet for which the lipid content was 100% soybean oil. The total cholesterol, LDL cholesterol, and HDL cholesterol
of animals consuming a diet with 67% LNGB (67LNGB-diet), were significantly lowered by 35, 49, and 29%, respectively, and
unesterified cholesterol increased by 17% compared with the animals fed a diet of 100% lipids from soybean oil (SB-diet).
In addition, the ratio of LDL cholesterol to HDL cholesterol was 27% lower in mink fed the 67LNGB-diet than those fed the
SB-diet. When the mink were fed the 67LNGB-diet, plasma PC, total phospholipids, lysoPC, and PI were lowered significantly
compared with the mink fed a SB-diet. Plasma total cholesterol was correlated with total phospholipids as well as with PC
(R=0.8, P<0.001). A significantly higher fecal excretion of unesterified cholesterol, cholesteryl ester, PC, lysoPC, and PE was observed
in the 67LNGB-fed mink compared with the SB-fed mink. We conclude that phospholipids from the 67LNGB-diet decreased plasma
lipoprotein levels, the LDL/HDL cholesterol ratio, and plasma phospholipid levels, especially lysoPC and PC, compared with
the highly unsaturated soybean oil. Our findings indicate that the decrease of plasma cholesterol is mainly caused by a specific
mixture of phospholipids containing a high level of PE, and not by the dietary FA composition. The lack of significant differences
in the level of plasma PE due to the diets indicates that most of the PE from LNGB has been converted to PC in the liver.
Thus, plasma cholesterol may at least be partly regulated by phospholipid methylation from PE to PC in the liver. 相似文献
7.
The influence of dietary excess (5%) of L-cystine on rat plasma lipoproteins was examined. After only one week of cystine
feeding, an increase in the plasma cholesterol level and a decrease in triglyceride levels were observed. The increase in
cholesterol level became greater when the duration of cystine-enriched diet increased until eight weeks (+131% after eight
weeks), but no further increase occurred between 8 and 20 weeks. This change was essentially due to the progressive increase
in cholesterol levels in high density lipoproteins (HDL) and in lipoproteins isolated between 1.040 and 1.063 g/ml, i.e.,
certain low density lipoproteins (HDL2), and containing mainly apoE-rich lipoproteins (HDL1). The decrease in plasma triglycerides resulted from that of chylomicrons and very low density lipoproteins (VLDL). The effects
observed after four or eight weeks of cystine feeding were maintained for eight weeks after replacing the cystine diet by
the standard diet. Ingestion of the standard diet containing either cholestyramine (2%) or probucol (0.25%) following eight
weeks of cystine feeding significantly decreased plasma cholesterol levels. It is concluded that cystine-fed rats are a useful
tool of investigation for understanding mechanisms leading to increased plasma cholesterol level and for hypocholesterolemic
drug trials. 相似文献
8.
Celastrus Orbiculatus Thunb. Reduces Lipid Accumulation by Promoting Reverse Cholesterol Transport in Hyperlipidemic Mice
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Ying Zhang Yanhong Si Lei Zhai Shoudong Guo Jilong Zhao Hui Sang Xiaofei Pang Xue Zhang Anbin Chen Shucun Qin 《Lipids》2016,51(6):677-692
Previously, we found that Celastrus orbiculatus Thunb. (COT) decreases athero‐susceptibility in lipoproteins and the aorta of guinea pigs fed a high‐fat diet, and increases high‐density lipoprotein (HDL). In the present study, we investigated the effect of COT in reducing lipid accumulation and promoting reverse cholesterol transport (RCT) in vivo and vitro. Healthy male mice were treated with high‐fat diet alone, high‐fat diet with COT (10.0 g/kg/d), or general fodder for 6 weeks. Serum levels of total cholesterol (TC), triglyceride (TG), HDL‐C, non‐HDL‐C, and 3H‐cholesterol in plasma, liver, bile, and feces were determined. Pathological changes and the levels of TC and TG in liver were examined. The expression of hepatic genes and protein associated with RCT were analyzed. COT administration reduced lipid accumulation in the liver, ameliorated the pathological changes, and lessened liver injury, the levels of TG, TC, and non‐HDL‐C in plasma were decreased significantly, and COT led to a significant increase in plasma HDL‐C and apolipoprotein A (apoA1). 3H‐cholesterol in plasma, liver, bile, and feces was also significantly increased in COT‐treated mice compared to controls. Both mRNA and protein expression of SRB1, CYP7A1, LDLR, ATP‐binding cassette transporters ABCA1, ABCG5, and LXRα were improved in COT‐treated mice. An in vitro isotope tracing experiment showed that COT and its bioactive ingredients, such as celastrol, ursolic acid, oleanolic acid, and quercetin, significantly increased the efflux of 3H‐cholesterol. They also increased the expression of SRB1, ABCA1, and ABCG1 significantly in macrophages. Our findings provided a positive role of COT in reducing lipid accumulation by promoting RCT. These effects may be achieved by activating the SRB1 and ABC transporter pathway and promoting cholesterol metabolism via the CYP7A1 pathway in vivo. The effective ingredients in vitro are celastrol, ursolic acid, oleanolic acid, and quercetin. 相似文献
9.
José M. Martins José A. Neves Amadeu Freitas José L. Tirapicos 《European Journal of Lipid Science and Technology》2010,112(3):295-303
This study was undertaken to investigate the effects of long term betaine intake on the cholesterol and lipid profile of Alentejano (AL) pigs. At ?36 kg body weight (BW), castrated male and female pigs fed a commercial (C) diet, were divided into two groups: i) Group C, consuming the C diet; and ii) Group CB, consuming the C diet supplemented with 1 g/kg betaine. Pigs were slaughtered at ?100 kg BW. Fasting plasma concentrations of protein, urea, glucose, TAG, phospholipids, homocysteine, total and LDL‐ and HDL‐cholesterol were determined. Liver TAG, phospholipids, and total and free cholesterol were analyzed, as well as total lipids, cholesterol contents, and fatty acid (FA) composition of M. semimembranosus and dorsal subcutaneous fat. Betaine supplemented pigs presented significantly higher plasma concentrations of TAG, phospholipids, cholesterol, and lipoprotein cholesterol. Dorsal subcutaneous fat cholesterol concentration was also significantly higher in CB than in C pigs. No differences were detected in the most abundant FA profile (including the unsaturated to saturated FA ratio) of muscle and subcutaneous fat tissues among treatments. These data suggest that betaine induces dyslipidemia, and increases cholesterol concentration in dorsal subcutaneous fat, without affecting the FA profile of M. semimembranosus and dorsal subcutaneous fat. 相似文献
10.
Three major density classes of lipoproteins and a residual protein (d>1.21) were isolated by ultracentrifugation from plasma
of fasted, fed normal, and choline-deficient rats. Lipid extracts were obtained from total plasma and the various density
classes of lipoproteins, and each extract was examined in detail by thin layer and gas chromatographies. The results indicated
essentially identical compositions of molecular species of phosphatidyl choline, which suggested their rapid equilibration
among the different plasma lipoprotein classes. In contrast, the molecular species of the triacylglycerols and cholesteryl
esters showed significant differences among the chylomicrons, very low and low, and high density lipoproteins, which excluded
the possibility of their ready equilibration in vivo. Omission of choline from diet resulted in a sharp and statistically
significant decrease in all lipid components of the very low and low density lipoproteins within 2 days. After 10 days of
choline deficiency, the lipid levels of chylomicrons and very low and low density lipoproteins were ca. one-half the levels
found in the choline supplemented animals, and there were discernible distortions in their lipid composition. Reintroduction
of choline led to a prompt return to normal levels and lipid composition of both chylomicron and very low and low density
lipoprotein fractions. The lack of equilibration of the triacylglycerols among the lipoprotein classes under normal conditions
and in choline deficiency demonstrates an as yet unrecognized source of compartmentation of plasma lipids. 相似文献
11.
Changes of lipoprotein composition have been mainly reported in conditions of sepsis. This study characterized compositional
changes in LDL and HDL during the acute phase response following cardiac surgery with cardiopulmonary bypass. Twenty-one patients
undergoing cardiac surgery were included in this study. Blood samples were drawn before operation and on day 2 post-surgery.
In parallel to plasma lipids and antioxidant status, lipoproteins were analyzed for lipid, apolipoprotein (apo), hydroperoxide
and alpha-tocopherol content. Beyond decreases in lipid concentrations and antioxidant defenses, cardiac surgery induced substantial
modifications in plasma lipoproteins. ApoB decrease in LDL fraction (−46%; P < 0.0001) reflected a marked reduction in the circulating particle number. LDL cholesteryl ester content relative to apoB
concentration remained unchanged post-surgery while triglyceride (+113%; P < 0.001), free cholesterol (+22%; P < 0.05) and phospholipid (+23%; P < 0.025) were raised relative to apoB indicating increased particle size. In HDL, an abrupt rise of apoSAA (P < 0.05) was observed together with a decrease of apoA1 (−22%; P < 0.005). Cholesteryl ester content in HDL fraction decreased in parallel to apoA1 concentration while triglycerides, free
cholesterol and phospholipids increased relative to apoA1. In contrast to unchanged alpha-tocopherol content, hydroperoxide
content was increased in LDL and HDL. By comparison to sepsis, cardiac surgery induces a comparable reduction in circulating
LDL but a more limited decrease in HDL particles. Furthermore, in contrast, cardiac surgery induces an increase in polar and
non-polar lipids, as well as of particle size in both LDL and HDL.
M. Hacquebard is recipient of a fellowship from the Danone Institute, Belgium. 相似文献
12.
Itaru Arimoto Chizuko Matsumoto Masafumi Tanaka Keiichirou Okuhira Hiroyuki Saito Tetsurou Handa 《Lipids》1998,33(8):773-779
Sphingomyelin (SM) and cholesterol (Chol) are major surface lipid constituents of plasma lipoproteins. We investigated the
effects of SM and Chol on the plasma clearance of lipid emulsions as a model for lipoprotein particles in rats. The presence
of Chol facilitated the removal of emulsion particles from plasma, whereas SM delayed particle removal. Preinjection of lactoferrin,
an inhibitor of the apolipoprotein E (apoE) receptor, revaled that the differences in clearance of emulsions were due to the
differences in affinity for the apoE receptor. Measurement of apolipoprotein binding suggested that the balance of apoE and
apoC (apoC-II and apoC-III) bound to emulsions caused the difference in plasma clearance of emulsion particles. That is to
say, SM in the emulsion surface decreased binding of apoE, which led to a longer circulation of emulsion particles in plasma.
Chol, on the other hand, decreased the ratio of apoC to apoE, which may have promoted emulsion uptake through the apoE receptor.
We also examined in vitro lipolysis using immobilized lipoprotein lipase (LPL) in a heparin affinity column. Lipolysis rates were significantly reduced
by the incorporation of SM into the emulsion surface, but not by the incorporation of Chol, indicating that SM in the lipoprotein
surface is an important lipid component regulating LPL-mediated lipolysis. Our results suggest that the presence of SM and
Chol in the lipoprotein surface plays an important role in the circulation behavior and LPL-mediated lipolysis of lipid emulsions
through their effect on the selectivity of plasma protein binding. 相似文献
13.
An important factor which determines the movement of cholesterol in and out of the cells is the free cholesterol (FC)/esterified
cholesterol (EC) ratio in the plasma. Although this ratio has been shown to be increased in several types of malignancies
in humans as well as experimental animals, it is not known whether such an abnormality is found in breast cancer patients.
Furthermore, the reasons for such an increase in cancer patients are unknown. We studied the plasma lipid composition and
the activity of lecithin-cholesterol acyltransferase (LCAT), the enzyme responsible for the formation of most of EC in human
plasma, in 12 women with breast cancer and 9 agematched control women. The plasma EC concentration was found to be significantly
decreased in cancer patients, whereas the FC concentration was unchanged, leading to increased FC/EC ratios (P<0.05). The concentration of phosphatidylcholine, the acyl donor in the LCAT reaction, was decreased significantly, whereas
all other phospholipids were unaffected. The cholesterol-esterifying activity of LCAT was significantly lower in cancer patients,
whether assayed with endogenous substrates (P<0.05), or with an exogenous substrate (P<0.01). However, another function of the enzyme, namely the lysolecithin acyltransferase activity, was increased (P<0.02), indicating that the enzyme concentration in plasma may not be decreased. These results show that the increase in the
FC/EC ratio in cancer patients is due to an impaired esterification of cholesterol by plasma LCAT, probably due to an alteration
in the composition of substrate lipoproteins, or the presence of an inhibitory factor. 相似文献
14.
Free cholesterol of plasma low density lipoproteins (LDL) and high density lipoproteins (HDL) of the rat was high and that
of plasma very low density lipoproteins (VLDL) was low during the dark period of the diurnal cycle. Variations in the esterified
plasma sterols were inconsistent. Free methyl sterols were high in all lipoproteins during the dark phase. Simultaneously,
the incorporation of14C-acetate into nonsaponifiable sterols and the concentrations of free methyl sterols and cholesterol in the liver were elevated. 相似文献
15.
Pérez-Martínez P Pérez-Jiménez F Ordovás JM Moreno JA Marín C Moreno R Jiménez-Gómez Y Paniagua JA López-Miranda J 《Lipids》2007,42(2):143-150
Apolipoprotein (apoB) plays a fundamental role in the transport and metabolism of plasma triacylglycerols (TAGs) and cholesterol.
Several apoB polymorphic sites have been studied for their potential use as markers for coronary heart disease in the population.
In view of the importance of apoB in postprandial metabolism, our objective was to determine whether the presence of the -516C/T
polymorphism in the APOB gene promoter could influence postprandial lipoprotein metabolism in healthy subjects. Forty-seven volunteers who were homozygous
for the E3 allele at the APOE gene were selected (30 homozygous for the common genotype (C/C) and 17 heterozygotes for the
-516T allele (C/T). They were given a fat-rich meal containing 1 g fat and 7 mg cholesterol per kg body weight and vitamin
A 60,000 IU/m2 body surface. Fat accounted for 60% of calories, and protein and carbohydrates for 15 and 25% of energy, respectively. Blood
samples were taken at time 0, every 1 h until 6 h, and every 2.5 h until 11 h. Total cholesterol and TAGs in plasma, and cholesterol,
TAGs and retinyl palmitate in triacylglycerol-rich lipoproteins (large and small triacylglycerol-rich lipoproteins) were determined
by ultracentrifugation. Individuals carrying the C/T genotype presented greater postprandial concentrations of TAGs in small
triacylglycerol-rich lipoproteins than did carriers of the C/C genotype (P = 0.022). Moreover, C/T individuals presented higher concentrations of plasma TAGs during the postprandial period than did
C/C subjects (P = 0.039). No other statistically significant genotype-related differences for other parameters were observed. These results
suggest that the presence of the genotype C/T is associated with a higher postprandial response. Thus, the allele variability
in the -516C/T polymorphism in the APOB gene promoter may partly explain the interindividual differences in postprandial lipemic response in healthy subjects. 相似文献
16.
Dergunov AD 《Lipids》2011,46(11):1075-1079
The kinetics of lecithin:cholesterol acyltransferase(LCAT, EC 2.3.1.43)-catalyzed generation of cholesteryl ester in discoidal
high density lipoproteins (HDL) was analyzed in terms of initial binding of LCAT to the disc surface followed by a three-state
reaction of the hydrolysis of phosphatidylcholine sn-2 ester bond and acyl-enzyme formation. Cholesterol was considered as alcoholic nucleophile that increases the solvolysis
rate of acyl-LCAT. The raw kinetic data of Sparks et al. (J Biol Chem 270:5151–5157, 1995) for four preparations of reconstituted discoidal HDL with a constant level of apolipoprotein A-I and palmitoyloleoylphosphatidylcholine
per disc but with cholesterol in a lipid phase continuously increasing from 2.1 to 12.5 mol%, were analyzed in terms of the
kinetic equation and a complete set of rate constants was obtained. Data at high cholesterol content do not indicate a saturation
phenomenon, thus giving no evidence for a binding of cholesterol to the enzyme. This analysis may be used in the study of
LCAT activation by exchangeable apolipoproteins and contribution of the HDL structure. 相似文献
17.
Severe iron deficiency affects lipid metabolism. To investigate whether moderate iron depletion also alters lipid variables—including
lipid levels in serum and liver, hepatic lipogenesis, and fatty acid composition indicative of an impaired desaturation—we
carried out experiments with rats fed 9, 13, and 18 mg iron/kg diet over a total of 5 wk. The study also included three pair-fed
control groups and an ad libitum control group, fed with 50 mg iron/kg diet. The iron-depleted rats were classified as iron-deficient on the basis of reduced
serum iron, hemoglobin concentration, and hematocrit. All moderately iron-deficient rats had significantly lower cholesterol
concentrations in liver and serum lipoproteins than their pair-fed controls. Rats with the lowest dietary iron supply had
higher concentrations of hepatic phosphatidylcholine (PC) and phosphatidylethanolamine (PE), lower activities of glucose-6-phosphate
dehydrogenase, malic enzyme and fatty acid synthase, and higher triacylglycerol concentrations in serum lipoproteins than
the corresponding pair-fed control rats. Moderate iron deficiency also depressed the serum phospholipid level. Moreover, several
consistent significant differences in fatty acid composition of hepatic PC and PE occurred within moderate iron deficiency,
which indicate impaired desaturation by Δ-9 and Δ-6 desaturases of saturated and essential fatty acids. We conclude that lipid
variables, including cholesterol in liver and serum lipoproteins as well as fatty acid desaturation, reflect the gradations
of iron status best and can be used as an indicator of the degree of moderate iron deficiency. 相似文献
18.
The activities of lipoprotein lipase in postheparin plasma, retroperitoneal adipose and gastrocnemius muscle tissues were
determined in the rats fed 2.8 ppm of dietary zinc for eight weeks, as compared with pair-fed and ad libitumfed rats given
30.8 ppm of zinc. The postheparin lipoprotein lipase activity, as determined by using a lipid emulsion labeled with [3H]triolein as the substrate, was significantly lower in the first group of rats, relative to that in the second and third
groups. Tissue lipoprotein lipase activities were compared using the lipid emulsion and activator serum obtained from the
zinc-deficient rats and the ad libitum-fed rats. The activator sera were devoid of very low density and low density lipoproteins,
but enriched in high density lipoproteins. Muscle lipoprotein lipase activities were significantly lower when assayed with
the activator serum from the zinc-deficient compared with the activities determined with the activator serum from the ad libitum-fed.
Similarly, muscle lipoprotein lipase activities were lower in all groups when [3H]-triolein-labeled chylomicrons from the zinc-deficient were used as the substrate, compared with the activities determined
using the chylomicrons from the ad libitum-fed. Lipoprotein lipase activities in the adipose tissues were not affected by
the different sources of the activator sera and chylomicrons. The results strongly suggest that the decrease in postheparin
lipoprotein lipase activity in zinc deficiency is not due to changes in tissue lipoprotein lipase enzyme per se, but to compositional
alterations in with regard to C apolipoproteins, modulators of lipoprotein lipase activity.
Presented in abstract form at the 71st annual meeting of the Federation of American Societies for Experimental Biology.Fed. Proc. 46:1472, 1987. 相似文献
19.
Dietary oligofructose lowers triglycerides,phospholipids and cholesterol in serum and very low density lipoproteins of rats 总被引:3,自引:0,他引:3
Maria Fiordaliso Nadine Kok Jean-Pierre Desager Fabienne Goethals Dominique Deboyser Marcel Roberfroid Nathalie Delzenne 《Lipids》1995,30(2):163-167
The present study was aimed at answering the question why feeding rats an oligofructose (OFS) supplemented diet could cause
a significant reduction in plasma lipid levels. Daily administration of a 10% (w/w) OFS-containing diet to normolipidemic
male rats resulted in a decrease in plasma triglycerides, phospholipids and cholesterol. The triglyceride-lowering effect
was observed after one week and lasted for at least 16 wk and was associated with a reduction in plasma very low density lipoproteins,
indicating that the hypolipidemic effect of OFS may be due to changes in liver lipid metabolism. We therefore tested whether
OFS feeding modified the capacity of the liver to synthesize triglycerides from free fatty acids. Hepatocytes isolated from
livers of control and OFS-fed rats were incubated in the presence of [1-14C]palmitate, and both intracellular and extracellular [14C]triglyceride formation were quantified. We found that chronic feeding of an OFS-supplemented diet to rats significantly
reduced the capacity of isolated hepatocytes to synthesize triglycerides from palmitate. The results suggest that, like other
soluble dietary fibers, OFS significantly alters liver lipid metabolism, resulting over time in a significant reduction in
plasma triglyceride, phospholipid and cholesterol levels. 相似文献
20.
The effects of orally administered polyunsaturated phosphatidylcholine (PPC) on plasma lipids, lipoproteins and platelet function
and composition were studied in seven healthy male volunteers. PPC (Nattermann & Cie, GmbH, Cologne, Federal Republic of Germany),
10 g/day, was given for a 6-week period after a 4-week wash out; laboratory tests were repeated after a further 4-week period
after the end of treatment. PPC did not appear, during treatment, to modify the levels of plasma total cholesterol and triglycerides.
High density lipoprotein (HDL) cholesterol levels were, however, increased after six weeks of PPC. The most dramatic changes
occurred in platelet membrane composition: the total lipid/total protein and the cholesterol/protein ratios were reduced significantly,
whereas increases of the phospholipid/total lipid ratio and of the linoleic acid membrane content were observed. Platelet
function tests, both in whole blood and in platelet rich plasma, were not modified. Similarly, the thromboxane B2 formation after standard stimuli and the sensitivity to exogenous prostaglandin I2 also were unchanged. During the final wash out period following treatment, a reduction of plasma total and low density lipoprotein
(LDL) cholesterol levels also was recorded. PPC appears to be capable of modulating lipid exchanges between cell membranes
and the plasma compartment. 相似文献