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1.
Response of free and esterified plasma cholesterol levels in the mongolian gerbil to the fatty acid composition of dietary lipid 总被引:2,自引:0,他引:2
The present study was undertaken to investigate the potential suitability of the Mongolian gerbil as a useful animal model
to study the effects of dietary fats on plasma cholesterol levels. Semipurified diets containing either 20% lard, 20% safflower
oil, or 19.5% beef tallow +0.5% safflower oil were equalized to contain 0.01% cholesterol and 0.05% plant sterol and were
fed for a four week experimental period. The proportions of total calories contributed by fat, protein and carbohydrate (starch/sucrose
ratio of 2∶1) were 40, 14 and 46%, respectively, so as to approach the distribution of calories within the average North American
diet. Free, esterified, and total plasma cholesterol levels of male gerbils were determined weekly by gas liquid chromatography
after drawing blood via a serial sampling technique. After 1, 2, 3, and 4 weeks of feeding the experimental diets, total cholesterol
levels were lowest in the safflower oil fed animals; the corresponding values were 19–64% greater in gerbils fed lard and
68–91% greater in those consuming the beef tallow diet. Cholesterol in the free form generally responded more dramatically
to the type of dietary lipid than did cholesterol in the ester form. Irrespective of the type of dietary lipid or the length
of the feeding trial, 18–23% of the total plasma cholesterol was in the free form and 77–82% was present as the ester. In
view of the similarity to the human of the relative proportions of free versus esterified cholesterol, the type of cholesteryl
esters, and their response to dietary manipulation, the gerbil appears to be a useful animal model for studying the regulatory
effect of dietary lipid on plasma cholesterol levels.
Presented in part at the A.O.C.S. Annual Meeting, San Francisco, CA, May 1979. 相似文献
2.
Lynnette S. Walsh Hentges Donald C. Beitz Norman L. Jacobson A. Dare McGilliard Jeffrey J. Veenhuizen 《Lipids》1985,20(11):735-742
In a 2×2 factorial arrangement, miniature pigs were fed four diets containing vegetable protein/fat (soybean) and animal protein
(egg white)/fat (beef tallow) to demonstrate the effects of protein and fat source on total plasma cholesterol, lipoprotein
distribution, low density lipoprotein (LDL) composition, and plasma clearance of LDL-cholesterol and protein. Beef tallow
consumption resulted in greater plasma cholesterol concentration, decreased LDL-cholesterol concentration, and a lower LDL-cholesterol
to LDL-protein ratio than did consumption of soybean oil. High density lipoprotein (HDL)-cholesterol concentration was increased
by beef tallow consumption. Cholesterol percentage by weight in LDL was significantly greater in pigs consuming soybean oil
than those consuming beef tallow. Percentages by weight of protein, triglyceride and phospholipid in LDL were not significantly
different in any group. Dietary protein source had no significant effect on total plasma cholesterol concentration, lipoprotein
concentration or LDL composition. Egg white consumption decreased fractional catabolic rate and irreversible loss of LDL-cholesterol
and LDL-protein when compared with consumption of soy protein. Dietary fat source had no consistent effect on LDL clearance
from plasma. Dietary fat and protein seemed to influence lipoprotein metabolism by different mechanisms. Fat source altered
lipoprotein concentration and LDL composition, whereas protein source affected the removal rate of LDL from plasma.
Data taken from a dissertation submitted to Iowa State University by L. S. Walsh Hentges as partial fulfillment of the requirements
for the Ph.D. degree. A preliminary paper, was presented at the meeting of the American Oil Chemists' Society in Dallas, Texas,
May, 1984. 相似文献
3.
Male weanling rats were fed semi-synthetic diets high in saturated fat (beef tallow) vs high in linoleic acid (safflower oil)
with or without high levels of α-linolenic acid (linseed oil) for a period of 28 days. The effect of feeding these diets on
cholesterol content and fatty acid composition of serum and liver lipids was examined. Feeding linseed oil with beef tallow
or safflower oil had no significant effect on serum levels of cholesterol. Serum cholesterol concentration was higher in animals
fed the safflower oil diet than in animals fed the beef tallow diet without linseed oil. Feeding linseed oil lowered the cholesterol
content in liver tissue for all dietary treatments tested. Consumption of linseed oil reduced the arachidonic acid content
with concomitant increase in linoleic acid in serum and liver lipid fractions only when fed in combination with beef tallow,
but not when fed with safflower oil. Similarly, ω3 fatty acids (18∶3ω3, 20∶5ω3, 22∶5ω3, 22∶6ω3) replaced ω6 fatty acids (20∶4ω6,
22∶4ω6) in serum and liver lipid fractions to a greater extent when linseed oil was fed with beef tallow than with safflower
oil. The results suggest that the dietary ratio of linoleic acid to saturated fatty acids or of 18∶3ω3 to 18∶2ω6 may be important
to determine the cholesterol and arachidonic acid lowering effect of dietary α-linolenic acid. 相似文献
4.
Comparative effects of feeding dietary linoleic (safflower oil) and α-linolenic (linseed oil) acids on the cholesterol content
and fatty acid composition of plasma, liver, heart and epididymal fat pads of rats were examined. Animals fed hydrogenated
beef tallow were used as isocaloric controls. Plasma cholesterol concentration was lower and the cholesterol level in liver
increased in animals fed the safflower oil diet. Feeding the linseed oil diet was more effective in lowering plasma cholesterol
content and did not result in cholesterol accumulation in the liver. The cholesterol concentration in heart and the epididymal
fat pad was not affected by the type of dietary fatty acid fed. Arachidonic acid content of plasma lipids was significantly
elevated in animals fed the safflower oil diet and remained unchanged by feeding the linseed oil diet, when compared with
the isocaloric control animals fed hydrogenated beef tallow. Arachidonic acid content of liver and heart lipids was lower
in animals fed diets containing safflower oil or linseed oil. Replacement of 50% of the safflower oil in the diet with linseed
oil increased α-linolenic, docosapentaenoic and docosahexaenoic acids in plasma, liver, heart and epididymal fat pad lipids.
These results suggest that dietary 18∶2ω6 shifts cholesterol from plasma to liver pools followed by redistribution of 20∶4ω6
from tissue to plasma pools. This redistribution pattern was not apparent when 18∶3ω3 was included in the diet. 相似文献
5.
Injections of [24-14C] chenodeoxycholate and3H-cholate were made by heart puncture into 300 g male rats that bore T-cannulas in their bile ducts. The animals had been
raised on diet A, containing glucose, cholesterol and cholate, or diet B, containing sucrose and cholesterol; each of the
diets contained 5% safflower oil or 5% beef tallow as variables. From analysis of bile samples collected from the T at intervals
over a 5 day period, it was observed that the safflower oil group fed diet B had a 17% shorter cholate half-life, a 29% larger
cholate pool size and 52% higher rate of cholate synthesis than those fed beef tallow in the same diet. The safflower group
fed diet A also had a larger cholate pool size, but synthesis and half-life were obscured by cholate feeding. Chenodeoxycholate
turnover data were not obtainable because the decay curves were bimodal for all treatments and hence did not conform to a
simple pool model. It is concluded that dietary safflower oil causes more rapid formation of cholate than does dietary beef
tallow in the cholesterol-fed rat.
Journal Paper No. 4952 AES, Purdue University. 相似文献
6.
Omega-3 fatty acids influence the function of the intestinal brush border membrane. For example, the omega-3 fatty acid eicosapentaenoic
acid (20∶5ω3) has an antiabsorptive effect on jejunal uptake of glucose. This study was undertaken to determine whether the
effect of feeding α-linolenic acid (18∶3ω3) or EPA plus docosahexaenoic acid (22∶6ω3) on intestinal absorption of nutrients
was influenced by the major source of dietary lipid, hydrogenated beef tallow or safflower oil. Thein vitro intestinal uptake of glucose, fatty acids and cholesterol was examined in rats fed isocaloric diets for 2 weeks: beef tallow,
beef tallow + linolenic acid, beef tallow + eicosapentaenoic acid/docosahexaenoic acid, safflower oil, safflower oil + linolenic
acid, or safflower oil + eicosapentaenic acid/docosahexaenoic acid. Eicosapentaenoic acid/docosahexaenoic acid reduced jejunal
uptake of 10 and 20 mM glucose only when fed with beef tallow, and not when fed with safflower oil. Linolenic acid had no
effect on glucose uptake, regardless of whether it was fed with beef tallow or safflower oil. The jejunal uptake a long-chain
fatty acids (18∶0, 18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3 and 22∶6ω3) and cholesterol was lower in salfflower oil than with beef tallow.
When eicosapentaenoic acid/docosahexaenoic acid was given with beef tallow (but not with safflower oil), there was lower uptake
of 18∶0, 20∶5ω3 and cholesterol. The demonstration of the inhibitory effect of linolenic acid or eicosapentaenoic acid/docosahexaenoic
acid on cholesterol uptake required the feeding of a saturated fatty acid diet (beef tallow). These changes in uptake were
not explained by differences in the animals’ food intake, body weight gain or intestinal weight. Feeding safflower oil was
associated with an approximately 25% increase in the jejunal and ileal mucosal surface area, but this increase was prevented
by combining linolenic acid or eicosapentaenoic acid/docosahexaenoic acid with safflower oil. Different inhibitory patterns
were observed when mixtures of fatty acids were present together in the incubation medium, rather than in the diet: for example,
when 18∶0 was in the incubation medium with 20∶4ω6, the uptake of 20∶4ω6 was reduced, whereas the uptake was unaffected by
18∶2ω6 or 20∶5ω3. Thus, (1) the inhibitory effect of eicosapentaenoic acid/docosahexaenoic acid on jejunal uptake of glucose,
fatty acids and cholesterol was influenced by the major dietary lipid, saturated (beef tallow) or polyunsaturated fatty acid
(safflower oil); and (2) different omega-3 fatty acids (linolenic acid versus eicosapentaenoic acid/docosahexaenoic acid)
have a variable influence on the intestinal absorption of nutrients. 相似文献
7.
Effects of diets high in saturated fat and cholesterol on the lipid composition of canine platelets 总被引:1,自引:0,他引:1
The phospholipid composition of platelets from dogs on various experimental diets was determined. Thyroidectomized foxhounds
were fed a control diet or the control diet supplemented with (1) beef tallow, (2) beef tallow and cholesterol, or (3) beef
tallow, cholesterol, and safflower oil for 23 weeks prior to isolation of platelets. Platelets from animals fed the control
diet contained 36.7% phosphatidylcholine (PC), 22.8% phosphatidylethanolamine (PE), 18.4% sphingomyelin (Sph), 11.8% phosphatidylserine
(PS), 6.3% phosphatidylinositol (PI), and 2.2% lysophosphatidylcholine. The PE was 77.6% in the plasmalogen form. No highly
significant changes in the phospholipid class composition resulted from the experimental diets. Cholesterol supplementation
of the diets, however, caused consistent alterations in the fatty acid compositions of the platelet phospholipids including
increases in the percentages of 18∶1ω9 (oleic acid), 18∶2ω6 (linoleic acid), and 20∶3ω6 (homo-gamma linolenic acid) and a
decrease in the percentage of 20∶4ω6 (arachidonic acid). Addition of safflower oil to the tallow-cholesterol diet partially
reversed these effects. These cholesterol-induced alterations in fatty acid composition could be due to exchange with plasma
lipids, de novo synthesis, or altered platelet metabolism. The mechanism remains to be determined.
Der. Nelson’s current affiliation is the Lipid Metabolism Branch, Division of Heart and Vascular Diseases, National Heart,
Lung, and Blood Institute. 相似文献
8.
Interaction between dietary protein and fat in triglyceride metabolism in the rat: Effects of soy protein and menhaden oil 总被引:4,自引:0,他引:4
The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids
in the regulation of triglyceridemia in rats. Male Sprague-Dawley rats (n=56) were subjected to 28-d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14%
w/w): (i) casein-menhaden oil, (ii) casein-beef tallow, (iii) soy protein-menhaden oil, and (iv) soy protein-beef tallow.
Significant protein-lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination
of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by
substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol
remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless
of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef
tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect
on post-heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia
relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when
rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be
mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil. 相似文献
9.
l-Carnitine plays an important role in the mitochondrial uptake of long-chain fatty acids in mammals. It has recently been
shown that this compound has a marked hypo-cholesterolemic effect when used in conjunction with lipid-rich diets. The aim
of this study was to investigate the effects of l-carnitine on the fatty acid composition of plasma lipoproteins in rabbits fed with different diets. Four different groups
were investigated: group I (standard diet), group II (standard diet supplemented with l-carnitine at 80 mg/kg), group III (standard diet supplemented with 0.5% cholesterol), and group IV (standard diet supplemented
with 0.5% cholesterol plus l-carnitine at 80 mg/kg). The feeding period was 126 d. Total plasma cholesterol was indistinguishable in groups I and II,
but increased nearly 40-fold in group III. This increment was reduced by 50% in group IV. Correspondingly, total cholesterol
content in lipoprotein fractions [very low density lipoprotein (VLDL), low density lipoprotein (LDL), high density lipoprotein
(HDL) separated by agarose gel chromatography was the same for groups I and II, while for animals fed a cholesterol-rich diet
(III) total cholesterol in VLDL+LDL increased nearly 100-fold when compared with groups I and II but, again, the increment
was reduced by 50% in group IV. In contrast, total cholesterol in HDL increased only fivefold for both groups III and IV when
compared with groups I and II, indicating no effects of l-carnitine on this parameter. The reduction of total cholesterol in VLDL+LDL particles in animals fed a cholesterol-rich diet
plus l-carnitine was associated with a marked decrease in the ratio of cholesteryl ester to free cholesterol and a dramatic increase
in their phospholipid content; opposite effects were observed for HDL. l-Carnitine induced a marked decrease in the saturated to unsaturated C16+C18 fatty acid ratio in cholesteryl esters associated with VLDL and LDL from animals fed with both normal and cholesterol-rich
diets. The opposite effect (a large increase in the saturated to unsaturated fatty acid ratio) was observed for both cholesteryl
esters and phospholipids associated with HDL in animals fed with both diets. The results suggested that the hypocholesterolemic
effects of l-carnitine could be associated with increased systemic breakdown of cholesteryl esters, a probable increase in reverse cholesterol
transport, and the stabilization of a phospholipid-based structure of VLDL+LDL particles. 相似文献
10.
Eicosapentaenoic acid is primarily responsible for hypotriglyceridemic effect of fish oil in humans 总被引:4,自引:0,他引:4
The aim of this study was to determine whether eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), or both, were responsible
for the triglyceride (TG)-lowering effects of fish oil. EPA (91% pure) and DHA (83% pure), a fish oil concentrate (FOC; 41%
EPA and 23% DHA) and an olive oil (OO) placebo (all ethyl esters) were tested. A total of 49 normolipidemic subjects participated.
Each subject was given placebo for 2–3 wk and one of the n-3 supplements for 3 wk in randomized, blinded trials. The target
n-3 fatty acid (FA) intake was 3 g/day in all studies. Blood samples were drawn twice at the end of each supplementation phase
and analyzed for lipids, lipoproteins, and phospholipid FA composition. In all groups, the phospholipid FA composition changed
to reflect the n-3 FA given. On DHA supplementation, EPA levels increased to a small but significant extent, suggesting that
some retroconversion may have occurred. EPA supplementation did not raise DHA levels, however, FOC and EPA produced significant
decreases in both TG and very low density lipoprotein (VLDL) cholesterol (C) levels (P<0.01) and increases in low density lipoprotein (LDL) cholesterol levels (P<0.05). DHA supplementation did not affect cholesterol, triglyceride, VLDL, LDL, or high density lipoprotein (HDL) levels,
but it did cause a significant increase in the HDL2/HDL3 cholesterol ratio. We conclude that EPA appears to be primarily responsible for TG-lowering (and LDL-C raising) effects of
fish oil. 相似文献
11.
This experiment was designed to evaluate the effects of dietary red wine phenolic compounds (WP) and cholesterol on lipid
oxidation and transport in rats. For 5 wk, weanling rats were fed polyunsaturated fat diets (n−6/n−3=6.4) supplemented or
not supplemented with either 3 g/kg diet of cholesterol, 5 g/kg diet of WP, or both. The concentrations of triacylglycerols
(TAG, P<0.01) and cholesterol (P<0.0002) were reduced in fasting plasma of rats fed cholesterol despite the cholesterol enrichment of very low density lipoprotein
+ low density lipoprotein (VLDL+LDL). The response was due to the much lower plasma concentration of high density lipoprotein
(HDL) (−35%, P<0.0001). In contrast, TAG and cholesteryl ester (CE) accumulated in liver (+120 and +450%, respectively, P<0.0001). However, the cholesterol content of liver microsomes was not affected. Dietary cholesterol altered the distribution
of fatty acids mainly by reducing the ratio of arachidonic acid to linoleic acid (P<0.0001) in plasma VLDL+LDL (−35%) and HDL (−42%) and in liver TAG (−42%), CE (−78%), and phospholipids (−28%). Dietary WP
had little or no effect on these variables. On the other hand, dietary cholesterol lowered the α-tocopherol concentration
in VLDL+LDL (−40%, P<0.003) and in microsomes (−60%, P<0.0001). In contrast, dietary WP increased the concentration in microsomes (+21%, P<0.0001), but had no effect on the concentration in VLDL+LDL. Cholesterol feeding decreased (P<0.006) whereas WP feeding increased (P<0.0001) the resistance of VLDL+LDL to copper-induced oxidation. The production of conjugated dienes after 25 h of oxidation
ranged between 650 (WP without cholesterol) and 2,560 (cholesterol without WP) μmol/g VLDL+LDL protein. These findings show
that dietary WP were absorbed at sufficient levels to contribute to the protection of polyunsaturated fatty acids in plasma
and membranes. They could also reduce the consumption of α-tocopherol and endogenous antioxidants. The responses suggest that,
in humans, these substances may be beneficial by reducing the deleterious effects of a dietary overload of cholesterol. 相似文献
12.
13.
Our objective was to determine the relative rates ofin vivo triglyceride (TG) secretion and the composition of very low density lipoproteins (VLDL) in rats fed different dietary saturated
fats. Male Sprague-Dawley rats (150–200 g) were fed diets containing 16% corn oil, or 14% butterfat, 14% beef tallow, 14%
olive oil, or 14% coconut oil plus 2% corn oil for 5 wk. Changes in plasma TG specific radioactivity were determined in individual,
unanesthetized fasted rats after injection of 100 μCi [2-3H]glycerol. Nonlinear regression analysis using a 2-compartment model was used to determine the fractional rate constant for
TG turnover in plasma. The plasma TG pool was 33–40% larger with beef tallow than with corn, olive or coconut oil feeding
(p<0.05), and 20% larger with beef tallow than with butterfat feeding. The rate of TG secretion into plasma (mg/min/100 g
body weight) was 60% higher in animals fed beef tallow than corn or coconut oil (p<0.05) and 26–33% higher in animals fed
beef tallow than olive oil or butterfat. Differences in VLDL composition (% wt) were also noted. Our data suggest that greater
TG secretion is the primary factor contributing to the larger TG pool with ingestion of beef tallow relative to butterfat,
corn or coconut oil. These results suggest that different dietary saturated fats have unique effects on TG metabolism in rats.
Presented in part at the 1990 meeting of the Federation of American Societies for Experimental Biology in Washington, D.C.
(see ref. 1). 相似文献
14.
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
15.
Studies investigated the effects of dietary fatty acid composition and saturation on the regulation of very low density lipoprotein
(VLDL) apo B flux, clearance, and conversion to low density lipoprotein (LDL) in guinea pigs fed semipurified diets containing
15% (w/w) corn oil (CO), lard (LA), or palm kernel oil (PK). Plasma cholesterol levels were highest with dietary PK (3.1±1.0
mmol/L) followed by LA (2.4±0.4 mmol/L) and CO (1.6±0.4 mmol/L) intake. VLDL particles were larger (P<0.05) in the LA (78±7 nm) and PK (69±10 nm) groups compared to animals fed CO (49±5 nm). VLDL-apo B fractional catabolic
rates (FCR) were highest in guinea pigs fed the LA diet (P<0.05) and VLDL apo B flux, estimated from VLDL 125I-apo B turnover kinetics, were higher in LA compared to PK or CO fed guinea pigs. In the case of PK consumption, the kinetic
estimates of VLDL apo B flux significantly underestimated rates compared to direct VLDL apo B secretion measurements and LDL
turnover analyses. These data demonstrate that differences in the composition and amount of saturated fatty acids have differential
effects on VLDL apo B flux, catabolism, and conversion to LDL which, together with changes in LDL receptor-mediated catabolism,
determine plasma LDL cholesterol levels in guinea pigs. The data also indicate that kinetic analysis of VLDL metabolism in
PK fed animals is inaccurate possibly due to the presence of a small, nonequilibrating pool of newly synthesized VLDL which
is rapidly converted to LDL. 相似文献
16.
Rats (8 wk of age) fed a conventional diet were shifted to diets containing 10% Oenothera biennis Linn oil (OBLO, linoleic acid +γ-linolenic acid) from a wild plant, evening primrose oil (EPO, linoleic acid +γ-linolenic
acid) from a cultivated plant, bio-γ-linolenic acid oil from mold (BIO, palmitic acid+oleic acid+linoleic acid+γ-linolenic
acid), safflower oil (linoleic acid), palm oil (PLO, palmitic acid+oleic acid+linoleic acid), or soybean oil (linoleic acid+α-linolenic
acid) with 0.5% cholesterol for 13 wk. Though there were no significant differences in the food intake among the groups, the
body weight gain of the OBLO group was significantly lower than that of other groups except for the BIO and PLO groups, and
that of the EPO and SPO groups were the highest among the groups. The liver weight of the OBLO group was significantly lower
than that of other groups, and that of the PLO group was the highest among the groups. The serum total cholesterol and very
low density lipoprotein (VLDL)+intermediate density lipoprotein (IDL)+low density lipoprotein (LDL) cholesterol concentrations
of the OBLO and EPO groups were consistently lower than those in the other groups. However, those of the BIO group were higher
than those in the OBLO and EPO groups. The liver cholesterol concentration of the PLO group was the highest among all groups
except for the EPO group. The fecal neutral sterol and bile acid extraction of the BIO group tended to increase compared to
other groups. The results of this study demonstrate that OBLO and EPO inhibit the increasing of serum total cholesterol and
VLDL+IDL+LDL-cholesterol concentrations in the presence of excess cholesterol in the diet compared with the other dietary
oils. 相似文献
17.
A series of short chain fatty acid derivatives of aminimides were shown to possess hypolipidemic activity in rats and mice.
Most of the agents tested lowered both serum cholesterol and triglyceride levels by at least 30% in mice and were effective
in hyperlipidemic induced mice. 1,1-Dimethyl-1-(2-hydroxypropyl)-amine mersitimide lowered serum cholesterol levels 41% and
serum triglyceride levels 56% at 20 mg/kg/day I.P. after 16 days. The same agent was active orally when administered to rats
with a 38% reduction in serum cholesterol and a 52% reduction in serum triglycerides after 14 days. The agents inhibited liver
acetyl CoA synthetase, ATP dependent citrate lyase and phosphatidate phosphohydrolase activities in vitro and in vivo. Reduction
of cholesterol, triglycerides, neutral lipids and phospholipid levels were noted in the livers of mice treated for 16 days.
In rat studies, cholesterol, triglyceride and phospholipid levels were reduced in liver, small intestine and the feces after
two weeks' dosing. The cholesterol content was reduced in the very low density lipoprotein (VLDL) and low density lipoprotein
(LDL) fractions but elevated in the high density lipoproteins (HDL). Triglyceride levels were lowered in the VLDL, and neutral
lipid levels were reduced in the chylomicron and VLDL fractions. 相似文献
18.
Dietary fat alters biliary lipid secretion in the hamster 总被引:1,自引:0,他引:1
Dietary fat has been found to alter the incidence of cholesterol gallstones in hamsters: butterfat intensifies while safflower
oil reduces lithiasis. We now report how dietary fat affects bile flow and biliary lipid secretion in this model. Male hamsters
were fed one of three experimental diets: a control diet (containing 0.3% cholesterol); control diet +4.0% butterfat; or control
diet +4.0% safflower oil. After three weeks, bile samples were collected via an external biliary fistula. The endogenous bile
acid pool was depleted for 120 min followed by increasing rates of taurocholate infusion for 160 min. Basal secretion of biliary
lipids was measured during the bile acid depletion period. Basal bile flow and bile acid output were not significantly different
in the three groups. Dietary butterfat increased basal cholesterol output compared to the control diet (0.037 vs. 0.025 μmol/min·kg,
respectively); safflower oil did not change cholesterol output (0.027 μmol/min·kg). Hamsters fed butterfat or safflower oil
secreted more phospholipid (0.171 and 0.178 μmol/min·kg, respectively) than controls (0.131 μmol/min·kg). The cholesterol/phospholipid
output ratio of the butterfat group was higher than the safflower oil group (0.220 vs. 0.153, respectively). Effects of dietary
fat on several relationships between bile flow and biliary lipid secretion were analyzed by linear regression using the data
for the entire bile collection period (bile acid depletion and taurocholate infusion). Butterfat and safflower oil did not
change either bile acid dependent or bile acid independent bile flow. Hamsters fed butterfat had a higher linkage coefficient
(slope) of cholesterol vs. bile acid output than the safflower oil group (0.023 vs. 0.009, respectively). The linkage coefficient
of phospholipid vs. bile acid output of the butterfat group was higher than the controls (0.278 vs. 0.185, respectively).
In summary, butterfat induced a high cholesterol and phospholipid secretion with a high cholesterol/phospholipid output ratio;
safflower oil induced a high phospholipid secretion with a low cholesterol/phospholipid output ratio. Butterfat and safflower
oil have different effects on biliary lipid secretion. These differences in biliary lipid secretion may explain, in part,
how butterfat and safflower oil differ in affecting gallstone formation in hamsters. 相似文献
19.
Rats were fed diets high in either saturated fat (beef tallow) or α-linolenic acid (linseed oil) or eicosapentaenoic and docosahexaenoic
acids (fish oil) with or without 2% cholesterol supplementation. Consumption of linseed oil and fish oil diets for 28 days
lowered arachidonic acid content of plasma, liver and heart phospholipids. Addition of 2% cholesterol to diets containing
beef tallow or linseed oil lowered 20∶4ω6 levels but failed to reduce 20∶4ω6 levels when fed in combination with fish oil.
Feeding ω3 fatty acids lowered plasma cholesterol levels. Addition of 2% cholesterol to the beef tallow or linseed oil diet
increased plasma cholesterol concentrations but not when fish oil was fed. Feeding the fish oil diet reduced the cholesterol
content of liver, whereas feeding the linseed oil diet did not. Dietary cholesterol supplementation elevated the cholesterol
concentration in liver in the order: linseed oil > beef tallow > fish oil (8.6-, 5.5-, 2.6-fold, respectively). Feeding fish
oil and cholesterol apparently reduced 20∶4ω6 levels in plasma and tissue lipids. Fish oil accentuates the 20∶4ω6 lowering
effect of dietary cholesterol and appears to prevent accumulation of cholesterol in plasma and tissue lipids under a high
dietary load of cholesterol. 相似文献
20.
High performance liquid chromatography with gel exclusion columns was used for quantitative measurement of plasma lipoproteins.
A combination of columns TKS 4000 PW and 3000 PW gave good separation of very low (VLDL), low (LDL) and high (HDL) density
lipoproteins. The area under each lipoprotein peak detected by absorbance at 280 nm was measured by digitizing and was expressed
as cm2. Purified lipoprotein standards isolated by ultracentrifugation were also chromatographed in increasing concentrations. The
area under the lipoprotein standard peak was linearly related to the amount of total protein over a wide range. The areas
of most of the measured plasma lipoproteins were within the linear range. The relationship between the area and the amount
of protein for each standard was used to quantitate the amount of protein and was expressed as mg/dl plasma. This technique
is simple and requires a small amount of plasma. The validated technique was applied to a large population of pedigreed baboons.
An average plasma lipoprotein profile of feral baboons on the chow diet was characterized by a high level of HDL (90.9±30.7
mg/dl) with a lesser amount of LDL (29.1±13.2 mg/dl). VLDL was present in much lower concentration (8.6±2.6 mg/dl). Feeding
a high cholesterol and high saturated fat (HCHF) diet raised both LDL (1.5-fold) and HDL levels (1.3-fold) without changing
VLDL levels. Progeny of sires with low response to dietary cholesterol increased their HDL protein when challenged with HCHF
diet without any change in their LDL or VLDL. Progeny of high-responding sires, however, had increases in both their HDL and
LDL levels when challenged with HCHF diet. The survey of lipoprotein profiles of the pedigreed baboon colony disclosed a number
of animals with interesting and unusual lipoprotein patterns. 相似文献