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1.
Triiodothyronine-induced alteration of the lipid pattern in rat-liver mitochondria and microsomes has been investigated. In
mitochondria, a 25% total cholesterol decrease and a 14% phospholipid increase have been detected. In these hyperthyroid rat
liver organelles, a strong decrease in the total cholesterol/phospholipid molar ratio occurs. On the contrary, in microsomes
from the same animals, a decrease of about 23% has been measured for both total cholesterol and phospholipids; hence, in this
fraction, the total cholesterol/phospholipid molar ratio is unaffected by hyperthyroidism. The liver mitochondrial phospholipid
composition, unlike the microsomal composition, is altered significantly in hyperthyroid rats; a 7.4% phosphatidylcholine
decrease is accompanied by a similar additive percentage increase of both phosphatidylethanolamine and cardiolipin. In regard
to total phospholipid fatty acid composition in liver microsomes from hyperthyroid rats, no variation has been observed compared
with the control rats, whereas in mitochondria from the same animals, a meaningful linoleic acid decrease with a similar arachidonic
acid increase has been found. In addition to fatty acid alteration, the separated mitochondrial phospholipid classes also
exhibit some increase in stearic acid. Among phospholipids, cardiolipin changes the most of the esterified fatty acids in
hyperthyroid rat liver. In this compound, a strong increase in the percentage of both palmitic and stearic acid and a 32.4%
decrease of linoleic acid have been found. 相似文献
2.
Relative susceptibility of microsomes from lung,heart, liver,kidney, brain and testes to lipid peroxidation: Correlation with vitamin E content 总被引:10,自引:0,他引:10
Rates of in vitro lipid peroxidation of microsomes and homogenates were found to vary widely among different tissues and species.
In rats and rabbits, lung microsomes peroxidized at a 25- to 50-fold lower rate than liver, kidney, testes and brain microsomes.
Heart microsomes peroxidized at a rate slightly greater than, but most similar to, lung microsomes. Comparison of tissue homogenates
also revealed the unique resistance of lung and heart to lipid peroxidation. The ratio of vitamin E to peroxidizable polyunsaturated
fatty acids in lung and heart microsomes was several-fold higher than in microsomes from the other tissues studied, which
accounted for the relative resistance of lung and heart to lipid peroxidation. Liposomes of extracted rat lung microsomal
lipid were also resistant to peroxidation and the amount of vitamin E contained in the lung lipid extract was sufficient to
confer the same degree of resistance when incorported into an equivalent amount of rat liver lipid. Higher rates of peroxidation
in mouse lung microsomes relative to rabbit, rat and human lung microsomes were similarly correlated with a lower ratio of
vitamin E to peroxidizable fatty acids in mouse lung microsomes. These data provide strong support for the role of vitamin
E as the major cellular antioxidant, especially in the highly oxygenated tissues of heart and lung, and demonstrate the utility
of the microsomal system in characterizing tissue differences in susceptibility to peroxidative membrane decomposition. 相似文献
3.
The lipid content, distribution and fatty acid composition of highly purified bovine liver nuclear membranes was determined
and compared to those of microsomes prepared in parallel. Contrasted with microsomes, nuclear membranes while containing nearly
the same levels of lipid had more cholesterol and total neutral lipid and less phospholipid. Phospholipid and neutral lipid
patterns generally were similar for the two types of membranes. The same fatty acids, in similar proportions, were observed
in respective total lipid, total polar lipid, phosphatidyl choline and phosphatidyl ethanolamine fractions of the two membrane
types. The microsomal lipid fractions contained slightly greater percentages of unsaturated fatty acids. With respect to previous
results from preparations contaminated with nonmenbranous nuclear material, purified fractions contained more total lipid
on a protein basis and more total unsaturated fatty acids. Only minor differences in levels and distribution of phospholipids
and neutral lipids were observed between the crude and highly purified fractions.
Purdue University AES Journal Paper No. 4482. 相似文献
4.
Liver mitochondrial and microsomal phosphatidyl cholines differing in the degree of unsaturation of their fatty acids have
been separated into four fractions by silver ion silica gel TLC. The levels of the four phosphatidyl choline fractions were
determined for male and female rats and mice, fetal and young rabbits, and female hamsters and guinea pigs. The sum of phosphatidyl
choline fractions 1, 2, and 3 of mitochondria and microsomes was greater in the female rat than in the male rat with the difference
being a reflection of a higher level of fraction 3 which contains arachidonic acid. The female rat has greater concentration
of phosphatidyl choline fractions 1 and 3 of mitochondria. Similar results were seen in mouse liver microsomes but not in
mitochondria. The levels of the individual four fractions varied from species to species. No change occurred in the levels
of the phosphatidyl choline fractions of fetal (−9 and −3 days) rabbits, but an increase was seen in the level of fraction
4 between day 3 and day 35 in both the mitochondria and microsomal fractions of liver. The concentration of mitochondrial
and microsomal protein, total phospholipid and total lecithin phosphorus were determined in rat, mouse, hamster and guinea
pig. The total phospholipid phosphorus/protein (μg/mg) of microsomes was greater in all species than that observed in mitochondria.
Liver microsomes contain 45–50% of total phospholipid phosphorus as lecithin whereas mitochondria contains 32–37%. The fatty
acid patterns of mitochondria and microsomal phosphatidyl cholines were determined and the ratio of palmitate to stearate
was greater than two for mice and hamsters and approximately 0.5 for rat and guinea pigs. 相似文献
5.
The fatty acid patterns of rat liver mitochondrial and microsomal phospholipids were analyzed from term fetuses, 1 and 4 days
old, and adult rats. The main fatty acids of phosphatidylethanolamine and-choline were stearic and palmitic acids, although
the patterns differed slightly. The fatty acid composition of corresponding phospholipids in mitochondria and microsomes was
similar. The fatty acid pattern of cardiolipin was dominated by linoleic acid. The most consistent feature of the developmental
changes in the fatty acid patterns of all phospholipids studied was a decrease in the relative amount of monounsaturated fatty
acids. The percentages of saturated fatty acids in phosphatidyl-ethanolamine and-choline increased during neonatal development.
It is suggested that the high levels of fetal monounsaturated fatty acids were due to low availability of polyunsaturated
fatty acids. 相似文献
6.
The effect of oral administration, for 24 or 48 hr, of different octadeca fatty acids containing a 9,12-dienoic structure
on the fatty acid composition and Δ9 desaturation activity of liver microsomes of rat fed a fat-free diet was studied. The
ethyl esters of linoelaidic and γ-linolenic acids, the methyl ester of linoleic acid and free columbinic acid were administered
to rats maintained on a fat-free diet. The supplementation of the fat-free diet with linoelaidate produced no relevant changes
in the fatty acid composition pattern of liver microsomes and did not modify the percentage of conversion of palmitic to palmitoleic
acid. The addition of linoleate or γ-linolenate to the fat-free diet returned liver microsome Δ9 desaturation activity toward
the control and partially restored the liver microsome fatty acid spectrum found in the fat-free diet. Columbinic acid (5-trans-9-cis,12-cis-18∶3), which cannot be transformed into arachidonic acid, also decreased the Δ9 desaturation activity enhanced by the fat-free
diet and evoked changes in the microsomal fatty acid composition similar to those produced by the ω6 fatty acids. These results
suggest that the modulation of Δ9 desaturase activity evoked by dietary administration of unsaturated acids of ω6 series would
depend on thecis double bond configuration of these acids. 相似文献
7.
Takehito Watanabe Hirofumi Fukushima Noboru Sasaki Shigenobu Umeki Yoshie Suezawa Yoshinori Nozawa 《Lipids》1983,18(6):423-427
Tetrahymena ISO cells, which have an unusually high level of iso odd-numbered fatty acids, were grown medium supplemented with various concentrations of isovalerate. There was a marked increase in the total proportion of iso odd-numbered fatty acids in supplemented whole cells (28.9 leads to 70.3%) and microsomes (37.7 leads to 84%), with a corresponding decrease in normal fatty acids, although no significant alteration of phospholipid composition was observed during 11 hr isovalerate-supplementation. Microsomal palmitoyl-CoA and stearoyl-CoA desaturase activities in isovalerate-supplemented cells decreased by 45.7% and 30.6% during 11 hr, respectively. NADH-cytochrome c reductase and NADH-ferricyanide reductase activities as well as the content of cytochrome b560ms, which is similar to mammalian microsomal cytochrome b5, were reduced in microsomes from 11 hr-supplemented cells, whereas NADPH-cytochrome c reductase activity was constant. It is suggested that the alteration of the cross-sectional area of lipid molecules in the bilayer, which results from the replacement of normal fatty acids with iso- 15:0 and iso- 17:1, would result in the decline of palmitoyl- and stearoyl-CoA desaturation in the isovalerate-supplemented cells, in order to maintain membrane fluidity at a functional level. 相似文献
8.
Alterations in the lipid and fatty acid composition of brush border membrane (BBM) of small intestine were studied in well-fed,
starved, and refed rats. The ratios of cholesterol/phospholipid (mol/mol), sphingomyelin/phosphatidylcholine (mol/mol), protein/lipid
(w/w), and free fatty acids (w/w) decreased whereas the total phospholipid (w/w) ratio and the double-bond index increased
in BBM of the intestine of the starved rat compared to that of the well-fed rat. Analyses of fatty acids showed higher percentage
of stearic and arachidonic acids whereas oleic and linoleic acids decreased under starvation. The acyl chain of starved rat
BBM was less ordered compared with that of well-fed rat BBM. On refeeding, these changes were restored to well-fed levels.
The change in membrane state under starvation is associated with alterations in the lipid and fatty acid composition of BBM
and may be responsible for functional changes that occur under nutritional stress. 相似文献
9.
We have studied the effect of various diets on the phospholipid fatty acid composition andin vitro Δ5 desaturase activity of hepatic microsomes derived either from the normal or streptozotocin-induced diabetic rat. The diets
studied were the standard rat chow diet and a basal fat-free diet supplemented either with 20 percent saturated fat, 20 percent
unsaturated fat, or 20 percent menhaden oil. Phospholipid fatty acid composition analysis revealed that the normal rat fed
the saturated fat or menhaden oil diet had significantly decreased arachidonate levels, consistent with decreased Δ5 desaturase
activities and decreased 18∶2n−6 intake. On the contrary, the unsaturated fat diet decreased dihomo-γ-linolenate and increased
arachidonate levels, without increased Δ5 desaturase activity. Streptozotocininduced diabetes resulted in decreased arachidonate
and Δ5 desaturase activity. The unsaturated fat diet fed to the diabetic rat also failed to correct this decreased Δ5 desaturase
activity. The unsaturated fatty acids in this diet also displaced a substantial amount of n−3 fatty acids in both normal and
diabetic microsomes, due to the competition between these two fatty acid families for incorporation into the membrane phospholipids.
Conversely, the menhaden oil diet fed to the normal and diabetic rats displaced n−6 fatty acids, reduced Δ5 desaturase activity,
and enhanced 22∶6n−3 incorporation into diabetic microsomes. 相似文献
10.
The changes in the lipids of liver tissues of nude mice with and without transplanted human cancerous tissues were studied
to clarify the effect of transplanted human tumor tissues on host liver lipid metabolism. The total lipid was extracted and
separated into phospholipid, triglyceride, and other fractions by thin layer chromatography. The amounts of methyl esters
of fatty acids of each lipid fraction were measured by quantitative gas liquid chromatography after each lipid fraction had
been subjected to methanolysis by 5% HCl-methanol. The phospholipid content of liver tissues of six tumor bearing nude mice
was increased and the triglyceride content decreased in comparison with these fractions in three control nude mice. The ratio
of the phospholipid fatty acid content to the triglyceride fatty acid content (phospholipid∶triglyceride [PL∶TG]) of six tumor
bearing nude mice was distributed between 7.6 and 33.5, whereas PL∶TG ratios of three control nude mice were distributed between
1.7 and 3.8. This result was similar to that reported for human liver tissues of patients with malignant neoplastic disease,
indicating that nude mice with transplanted human cancer may be useful for clarifying the mechanisms of the lipid-chemical
changes of liver tissues of patients with malignancies. 相似文献
11.
Studies are reported on the composition of the lipids of human liver and hepatoma tissues from male adults. Liver tissues
were obtained from individuals who died from causes other than liver disease or cancer. The hepatoma tissues were obtained
from individuals shortly after they succumbed to cancer. The total lipid of each tissue was fractionated quantitatively by
silicic acid column chromatography into neutral lipid, glycolipid, and phospholipid fractions. These fractions were analyzed
by thin layer chromatography and converted to methyl esters for analysis of their constituent fatty acids by gas liquid chromatography.
In comparison to liver tissue, the total amount of lipid in the hepatoma tissues was generally higher and more variable; the
lipid of one hepatoma was ca. 92% of the dry wt of the tissue. The greater lipid content of the hepatoma tissues was due to
the high percentage of neutral lipid. Except for one specimen, there was ca. the same amount of glycolipid in the hepatoma
as in the liver tissues, but the composition of the glycolipid fraction of the hepatoma lipid differed considerably, particularly
in the ganglioside fraction. The phospholipid fraction of hepatoma lipid was much lower than that of liver but exhibited only
quantitative differences in composition. No glyceryl ether diesters and only traces of plasmalogens of phosphatidyl choline
or phosphatidyl ethanolamine were detected in the liver and hepatoma lipids. The levels of monoenoic acids were higher and
those of linoleic and polyunsaturated fatty acids lower in the hepatoma lipids. Positional isomers of trienoic acids not normally
present in liver tissue were detected in hepatoma lipids. The abnormalities observed in lipid composition indicated interferences
in the regulatory processes of lipid metabolism in human hepatoma similar to those observed in animals. 相似文献
12.
Male F-344 rats were fed a choline-free (CF) diet, and changes in phospholipid content, phospholipid fatty acids and phospholipase
A2 activity in liver nuclei and microsomes were examined during the first 72 hr. Both nuclei and microsomes showed a decrease
in phosphatidylcholine (PC) content. Microsomes showed an increase in PC arachidonate while nuclei showed a decrease. Also,
microsomes showed increased activity of phospholipase A2 (PLA2) while nuclei did not. These observations are consistent with the hypothesis that the absence of diene conjugates in liver
microsomes in the rats on the CF diet may reflect the increased rate of removal of peroxidized fatty acids by phospholipase
A2. 相似文献
13.
Delta-6 and Δ5 desaturation activity of rat adrenal gland microsomes was studied to determine the effect of microsomal protein
and the substrate saturation curves. This tissue has a very active Δ6 desaturase for linoleic and α-linoleic acids and a Δ5
desaturase for eicosa-8,11,14-trienoic acid. The administration of epinephrine (1 mg/kg body weight) 12 hr before killing,
produced approximately a 50% decrease in desaturation of [1-14C]linoleic acid to γ-linolenic acid, [1-14C]α-linolenic acid to octadeca-6,9,12,15-tetraenoic acid and [1-14C]eicosa-8,11,14-trienoic acid to arachidonic acid. A 30% decrease in Δ5 desaturation activity was also shown after 7 hr of
epinephrine treatment. The changes on the oxidative desaturation of the same fatty acids in liver microsomes were similar.
No changes were observed in the total fatty acid composition of adrenal microsomes 12 hr after epinephrine treatment. Mechanisms
of action of the hormone on the biosynthesis of polyunsaturated fatty acids in the adrenal gland are discussed. 相似文献
14.
S. A. Rooney L. L. Nardone D. L. Shapiro E. K. Motoyama L. Gobran N. Zaehringer 《Lipids》1977,12(5):438-442
The phospholipid composition of type II alveolar epithelial cells from the rabbit was compared with that of alveolar macrophages,
lung lavage and lung tissue. In addition, the phospholipid composition of a human alveolar tumor cell line, which is morphologically
similar to type II cells, was examined. Phosphatidylcholine accounted for 48% of the total phospholipid in the type II cells,
41% in the tumor cells, and 30% in the macrophages. Phosphatidylcholine was 51% disaturated in the type II cells, 54% in lung
lavage, 39% in whole lung, 29% in lavaged lung and macrophages, and 16% in the tumor cells. Palmitic acid was the major fatty
acid in phosphatidylcholine from all samples with the exception of the tumor cells in which almost half of the fatty acids
were accounted for by oleic acid. The phospholipids of the type II cells were more similar to those of lung lavage, and thus
surfactant, than to lung tissue and macrophages. This is consistent with their supposed role in surfactant production. The
tumor cells, although morphologically similar to type II cells, were quite different with respect to phospholipid composition. 相似文献
15.
Streptozotocin diabetes in the rat alters liver microsomal membrane fatty acid composition. The present study was undertaken
to determine if such changes in fatty acid composition were due to changes in the amount of individual phosphoglycerides or
to disproportionate changes in fatty acid composition in any of the individual phosphoglycerides. The diabetic animals showed
a small increase in total microsomal phospholipid, which is due to a selective increase in the phosphatidylethanolamine fraction.
The changes in fatty acid composition in the total lipid extract (decreased palmitoleic, oleic and arachidonic acids and increased
linoleic and docosahexaenoic acids) from the diabetic animals were present in both the major phosphoglycerides, phosphatidylcholine
and phosphatidylethanolamine, with very little change in fatty acid composition in the phosphatidylserine and inositol fraction.
Further studies are necessary to delineate the cause of the abnormal membrane phospholipid composition in the diabetic animal.
Abbreviations: The abbreviated fatty acid nomenclature refers to the number of carbon atoms in the chain, the number of unsaturated
bonds, and the position of the first unsaturated bond counting from the terminal methyl group; thus arachidonic acid, 5,8,11,14-eicosatetraenoic
acid, is 20∶4ω6. 相似文献
16.
Twelve-week-old Landes male geese were overfed with corn for 21 d in order to induce liver steatosis (fatty liver). Lipid
composition of hepatocyte plasma membranes from fatty livers was compared to that of lean livers obtained from geese fed a
normal diet. The ratio cholesterol/phospholipids was higher in fatty hepatocyte plasma membranes (0.63 vs. 0.47), whereas
the phospholipid/protein ratio was less than half. Overfeeding induced changes in fatty acid composition of hepatocyte plasma
membranes, including a greater than twofold increase in the percentage of oleic acid (29.7 vs. 13.8%) and a somewhat lesser
increase in lauric, palmitic, and palmitoleic acid contents of plasma membrane lipids of fatty livers. A concomitant reduction
in the proportion of stearic acid (18.4 vs. 25.1%) was also observed. In fatty livers, the increased ratio of saturated to
polyunsaturated fatty acids (PUFA) (1.5 vs. 1.0) was related to a significant decrease in PUFA content. Among all the PUFA,
only the eicosatrienoic acid (20∶3n−9) percentage was increased by liver steatosis. Overfeeding with corn appeared to induce
competition between de novo synthesized and dietary fatty acids incorporated in hepatocyte plasma membranes. This resulted in an accumulation of de novo synthesized monounsaturated and derived fatty acids in plasma membranes from overfed birds. A defect in the incorporation
of linoleic acid and linoleic- and linolenic-derived PUFA was observed despite the high proportion of these essential fatty
acids in the diet. It was conclued that in overfed palmipeds, de novo hepatic lipogenesis prevails over dietary lipid intake to modulate lipid composition of the fatty liver plasma membrane. 相似文献
17.
The comparative incorporation of acetate into long chain fatty acids and acetyl carnitine by cell-free preparations of rat
heart has been investigated. Whereas the addition of 1 mM carnitine stimulated (45%) fatty acid synthesis by liver preparations
in citrate-containing media, fatty acid synthesis from acetate in rat heart homogenates under the same incubation conditions
was markedly depressed. This depression by carnitine of acetate incorporation into long chain fatty acids in 105,000 × g soluble
fractions of heart was associated with increased acetyl carnitine formation. Thus in heart tissue acetyl CoA is effectively
shuttled into acetyl carnitine and is unavailable for synthesis of fatty acids. These data are in agreement with results obtained
earlier in studies with perfused rat heart. A similar conversion of added acetyl CoA to the carntine derivative occurred when
labeled malonyl CoA was used as fatty acid precursor, again resulting in reduced fatty acid synthesis. It was shown by direct
measurement that acetyl carnitine formation in the absence of carnitine was greatest in heart mitochondria and least in microsomes.
In the presence of carnitine, acetyl carnitine formation was increased in all subcellular fractions, with the greatest change
again occurring with mitochondria. 相似文献
18.
The n-6 and n-3 fatty acid status of developing organs is the cumulative result of the diet lipid composition and many complex
events of lipid metabolism. Little information is available, however, on the potential effects of the saturated fatty acid
chain length (8:0–16:0) or oleic acid (18:1) content of the diet on the subsequent metabolism of the essential fatty acids
18:2n-6 and 18:3n-3 and their elongated/desaturated products. The effects of feeding piglets formulas with fat blends containing
either coconut oil (12:0±14:0) or medium chain triglycerides (MCT, 8:0±10:0) but similar levels of 18:1, 18:2n-6 and 18:3n-3,
or MCT with high or low 18:1 but constant 18:2n-6 and 18:3n-3 on the fatty acid composition of plasma, liver and kidney triglycerides,
phospholipids and cholesteryl esters, and of brain total lipid, were studied. Diet-induced changes in the fatty acid composition
of lipid classes were generally similar for plasma, liver and kidney. Dietary 18:1 content was reflected in tissue lipids
and was inversely associated with levels of 18:2n-6. Lower percentage of 18:2n-6, however, was not associated with lower levels
of its elongated/desaturated product 20:4n-6 but was associated with higher levels of 22:6n-3. Feeding coconut oilvs. MCT resulted in lower 18:1 levels in all lipids, and higher percentages of 20:4n-6 in tissue phospholipid. Increasing the
dietary n-6/n-3 ratio from 5 to 8 significantly increased tissue percentage of 18:2n-6 and decreased phospholipid 22:6n-3.
In contrast to plasma, liver and kidney, brain lipid fatty acid composition was not influenced by the formula saturated fatty
acid chain length, content of 18:1, or n-6/n-3 ratio. In summary, the studies show that the dietary requirement for n-6 and
n-3 fatty acids may be influenced by the nonessential saturated and monounsaturated fatty acids fed concurrently. 相似文献
19.
Arginine deficiency is associated with a marked increase in liver lipids in the rat. Triglyceride accumulation accounts for
most of the fatty infiltration. Cholesterol concentration per gram of liver increased approximately 280% above control rats
receiving dietary arginine. The percentage of phospholipids was significantly decreased in the arginine-deficient rat liver
compared to controls. The fatty acid composition revealed a significant reduction in the percentage of palmitic, palmitoleic,
oleic, and linoleic acids. However, both stearic and arachidonic acids were increased approximately 250 and 160%, respectively,
in arginine-deficient livers compared to controls. Arginine deficiency in the rat causes a marked alteration in lipid metabolism
similar to that observed with orotic acid feeding. The similarities of arginine deficiency and orotic acid feeding are discussed. 相似文献
20.
Changes in dietary lipid intake are known to alter the fatty acid composition of cardiac muscle of various animals. Because
changes in cardiac muscle membrane structure and function may be involved in the pathogenesis of arrythmia and ischemia, we
have examined the effects of dietary lipid supplements on the phospholipid distribution and fatty acid composition of rat
atria and ventricle following 20 weeks feeding of diets supplemented with either 12% sunflower-seed oil or sheep fat.
Neither lipid supplement produced significant changes in the proportions of cholesterol, total phospholipids or phosphatidylcholine,
phosphatidylethanolamine or diphosphatidylglycerol,—the phospholipid classes that together account for more than 90% of the
total phospholipids of rat cardiac muscle. Significant changes were found in the profiles of the unsaturated fatty acids of
all 3 phospholipid components of both atria and ventricle. Although similar, the changes between these tissues were not identical.
However, in general, feeding a linoleic acid-rich sunflower seed oil supplement resulted in an increase in the ω-6 family
of fatty acids, whereas feeding the relatively linoleic acid-poor sheep fat supplement decreased the level of ω-6 fatty acids
but increased the levels of the ω-3 family, resulting in major shifts in the proportions of these families of acids. In particular,
the ratio of arachidonic acid: docosahexaenoic acid (20∶4, ω-6/22∶6, ω-3), which is higher in all phospholipids of atria than
ventricle, is increased by feeding linoleic acid, primarily by increasing the level of arachidonic acid in the muscle membranes.
As dosahexaenoic acid does not occur in the diet, the increase in this acid which occurs after feeding animal fat, presumably
arises from increased conversion of the small amounts of linolenic acid in all diets when the amount of linoleic acid present
is reduced. 相似文献