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1.
The present study was designed to investigate the metabolism of the n−3 olyunsaturated fatty acids (PUFA) in adipose tissue
and its dependence upon dietary factors. Changes in the positional distribution of the fatty acids in triacylglycerols from
retroperitoneal adipose tissue were studied as a function of time on rats fed for 4 wk a diet enriched with fish oil. The
stereospecific analysis of triacylglycerols was based on random formation ofrac-1,2-diacylglycerols by Grignard degradation. This was followed by synthesis ofrac-phosphatidic acids and treatment with phospholipase A2. In the triacylglycerols of the fish oil diet, 57% of the total n−3 fatty acids were in position 3,i.e., two-thirds of 22∶5n−3 and 22∶5n−3 were esterified insn-3 position, whereas 22∶6n−3 was equally distributed in positions 2 and 3. After 4 wk of feeding fish oil, the fatty acid
composition of adipose tissue triacylglycerols reached a steady state. Half of the n−3 fatty acids were found in position
3, namely 75% of 22∶5n−3, 50% of 20∶5n−3 and 18∶4n−3 and 45% of 22∶6n−3, the latter being equally distributed in positions
2 and 3. This pattern of distribution resembled that found in triacylglycerols of the fish oil diet, except for a higher proportion
of 20∶5n−3 in adipose tissue in position 1 at the expense of position 3. Throughout the 4-wk period of fish oil feeding, the
distribution pattern of minor n−3 fatty acids (18∶4n−3 and 22∶5n−3) in adipose tissue triacylglycerols remained unchanged.
On the other hand, at the onset of fish oil feeding, 20∶5n−3 and 22∶6n−3 became concentrated in position 3, but thereafter
20∶5n−3 was progressively incorporated into position 1 and 22∶6n−3 into position 2. We thus conclude that n−3 fatty acids
are differentially esterified in triacylglycerols of white adipose tissue. Despite the complex sequence of hydrolysis and
acylation steps involved, the positional distribution of n−3 fatty acids was found to be similar in both the fish oil diet
and the stored fat, in contrast to what was observed for nonessential fatty acids. 相似文献
2.
A study was made of the influence of semisynthetic diets of low and high unsaturation on the fatty acid composition and desaturation-chain
elongation enzymatic activity of the liver microsomal fractions of male Sprague-Dawley rats of different ages. Groups of rats
were fed 5 or 20% coconut oil (CO), or a 5 or 20% mixture of corn and menhaden oils (3∶7) (CME) from weaning to 100 wk of
age. Growth rate and food consumption were measured during this period in which animals were sacrificed at 36, 57, 77 and
100 wk of age. Both the level and composition of the dietary fat supplements produced marked effects on the fatty acid composition
of the liver microsomal lipids. In general, the fatty acid composition of the microsomal fractions reflected that of the dietary
fat and was more unsaturated with the higher level of fat fed. The rate of conversion of linoleic to arachidonic acid in assays
performed in vitro with liver microsomal preparations from animals of the different groups also showed marked differences.
The 6-desaturase-chain elongation activity was higher in the 5% than 20% group and corresponded to the essential fatty acid
(EFA) status of the animals in these groups as represented by the triene-tetraene ratio of the microsomal lipid. The relationship
of the 6-desaturase activity to fatty acid composition of the microsomal lipid indicated that if varied directly with the
level of 20∶3ω9, 18∶1 and 16∶1 and was inhibited by arachidonic acid. The activity of the 6-desaturase enzyme system was lowest
in the liver microsomal fraction obtained from the animals fed the CME diets and appeared to be suppressed by the high levels
of 20∶5 and 22∶6 that accumulated in the microsomal lipid. Accordingly, the levels of arachidonic acid were lower in the microsomal
lipid of these groups than those of the corresponding CO groups in spite of a greater abundance of linoleic acid in the diet.
The data suggest that the activity of the 6-desaturase-chain elongation system is regulated by the fatty acid composition
of the microsomal lipid as influenced by the composition of the dietary fat. 相似文献
3.
The pattern of accumulation of triacylglycerols, their fatty acid compositions and the positional distribution of the fatty
acids at thesn-2- andsn-1,3-positions of the triacylglycerol molecules at progressive stages of oil palm fruit development were determined. There
was an exponential rate of increase of triacylglycerols and their fatty acids toward the end of fruit development. The fatty
acid composition of the triacylglycerols in the early stages of development, prior to active accumulation, was more or less
similar, but differed appreciably from the later stages, and the transition of fatty acid composition toward that of normal
palm oil occurred at around 16 wk after anthesis (WAA) and stabilized at 20 WAA. All fatty acids increased in terms of absolute
quantity. There was an overall consistency in fatty acid positional distribution, irrespective of development stage. More
saturated fatty acids were found to be esterified at thesn-1,3-positions and more unsaturated fatty acids at thesn-2-position of triacylglycerol. Higher rate of incorporation of 16:0 at the 1,3-positions during the active phase of triacylglycerol
synthesis was observed, while 18:1 acid exhibited a reverse trend. 相似文献
4.
Summary 1. Two liver oils (Elasmobranch) fromCarcharias melanopterus andPristis cuspidatus, caught off the Madras coast are studied, and their component fatty acids are reported.
2. The mixed acids were separated into three groups (varying unsaturation) of acids, and their methylesters were fractionated.
3. The liver oils are found to belong to the fourth group of Tsujimoto’s classification of Elasmobranch fish liver oils.Carcharias melanopterus liver oil contains 31.1% unsaturated acids (myristic 3.1, palmitic 18.4, stearic 9.5, and 0.1% arachidic) and 68.9% unsaturated
acids (C16 10.8, C18 19.7, C20 15.2, C22 17.1, C24 5.3%, and traces of C14 monoethenoid).Pristis cuspidatus liver oil contains 36.9% saturated acids (myristic 1.2, palmitic 22.9, stearic 12.7, and arachidic 0.1%) and 67.1% unsaturated
acids (C16 8.2, C18 28.5, C20 16.4, C22 5.2, C24 4.6%, and traces of C14 monoethenoid). The unsaturations of the different groups of acids are almost of the same order.
4. The abnormal content of saturated acids can be explained by the process of bio-hydrogenation. The relatively less amount
of saturated acids inCarcharias melanopterus liver oil along with its higher content of polyethylenic acids (C20 and above) points strongly to the possible presence of intermediate types of fats among the four groups of Elasmobranch oils. 相似文献
5.
Salo Gronowitz Tomas Klingstedt Magnus Munck Jan Glans Leif Svensson Ulf Hansson 《Lipids》1997,32(6):667-673
A number of triacylglycerols with branched acyl groups were prepared via 1,2-isopropylidene glycerol for the purpose of studying three different physical properties: gel point, refractive index,
and density. The monoacid triacylglycerols were prepared either via the corresponding acids or the acyl chlorides. 相似文献
6.
- A sample of liver oil of an Indian shark (Carcharias melanopterus) from the Arabian Sea has been studied.
- Tsujimoto's lithium salt acetone method has been adopted for the separation of the highly unsaturated acids from the mixed acids, which were further resolved into simpler groups with the help of Hilditch's modified lead salt ethanol method. The efficient column (E.H.P.) of Longenecker has been employed for fractionation in the present work.
- The present oil is found to belong to the IV group of Tsujimoto's classification of the Elasmobranch fish liver oils.
- The abnormal saturated acid content is discussed. The present analysis provides an additional instance of this peculiar group of Elasmobranch liver oils.
7.
Selim M. Erhan Robert Kleiman Terry A. Isbell 《Journal of the American Oil Chemists' Society》1993,70(5):461-465
The formation of estolides was detected during the studies on dimerization of meadowfoam oil fatty acids. By adjusting the
reaction conditions, it was possible to produce monoestolides with little dimer or trimer formations. Estolides have potential
use in lubricant, cosmetic and ink formulations and in plasticizers. This paper reports the conditions for production of estolides
from mixed meadow-foam fatty acids, commercial oleic acid, high-oleic sun-flower oil fatty acids,cis-5,cis-13-docosadienoic acid, petroselinic acid and linoleic acid. 相似文献
8.
9.
F. Comes M. Farines A. Aumelas J. Soulier 《Journal of the American Oil Chemists' Society》1992,69(12):1224-1227
Cherry seed oil, from the Rosaceae family, prunoid subfamily, is characterized by the existence of about 10% α-eleostearic
acid. The structure of the acid was proven by H and13C nuclear magnetic resonance. The triacylglycerols of this oil were identified and quantitated by highperformance liquid chromatography
by means of several types of detectors. α-Eleostearic acid was not found in the seeds of previously studied prunoids (almond,
peach, apricot and plum). The main fatty acids found in the seeds of cherry and other prunoids were linoleic (L), oleic (O)
and palmitic acids, and the major triacylglycerols were LLO, LOO and OOO. These chemical data support the botanical relationship
within the prunoid subfamily and show the proximity of cherry to the Chrysobalanaceae family. 相似文献
10.
Lennart Svensson 《Lipids》1983,18(3):171-178
The influence of dietary partially hydrogenated marine oils on distribution of phospholipid fatty acids in rat liver microsomes
was studied with particular reference to the metabolism of linoleic acid. Five groups of weanling rats were fed diets containing
20% (w/w) peanut oil (PO), partially hydrogenated peanut oil (HPO), partially hydrogenated Norwegian capelin oil (HCO), partially
hydrogenated herring oil (HHO), and rapeseed oil (RSO) for 10 weeks. The partially hydrogenated oils were supplemented with
linoleic acid corresponding to 4.6 cal % in the diets. Accumulation of linoleic acid and reduced amount of total linoleic
acid metabolites were observed in liver microsomal phospholipids from rats fed partially hydrogenated oils as compared to
PO feeding. The most striking effects on the distribution of ω6-polyunsaturated fatty acids was obtained after feeding HHO,
a marine oil with a moderate content oftrans fatty acids in comparison with HPO but rich in isomers of eicosenoic and docosenoic acids. Liver microsomal Δ6-as well as Δ6-desaturase activities as measured in vitro were reduced in rats kept on HHO as compared to PO dietary treatment. The results
obtained suggest that the dietary influence of partially hydrogenated marine oils on the metabolism of linoleic acid might
be better related to the intake of isomeric eicosenoic and docosenoic acids than to the total intake oftrans fatty acids. 相似文献
11.
12.
Male Sprague Dawley rats were fed semipurified diets containing 20% fat for 15 weeks. The dietary fats were corn oil, soybean
oil, palm oil, palm olein and palm stearin. No differences in the body and organ weights of rats fed the various diets were
evident. Plasma cholesterol levels of rats fed soybean oil were significantly lower than those of rats fed corn oil, palm
oil, palm olein or palm stearin. Significant differences between the plasma cholesterol content of rats fed corn oil and rats
fed the three palm oils were not evident. HDL cholesterol was raised in rats fed the three palm oil diets compared to the
rats fed either corn oil or soybean oil. The cholesterol-phospholipid molar ratio of rat platelets was not influenced by the
dietary fat type. The formation of 6-keto-PGF1α was significantly enhanced in palm oil-fed rats compared to all other dietary treatments. Fatty acid compositional changes
in the plasma cholesterol esters and plasma triglycerides were diet regulated with significant differences between rats fed
the polyunsaturated corn and soybean oil compared to the three palm oils. 相似文献
13.
Stearic acid as compared to myristate, palmitate, or oleate is poorly incorporated into triacylglycerol, a major lipid component
of very low density lipoprotein (VLDL). The present study investigated the effects of these fatty acids on VLDL metabolism
in cultured rat hepatocytes. All fatty acids stimulated [2-3H] glycerol incorporation into VLDL lipids and secretion of [3H]-labeled VLDL by hepatocytes. However, the rate of [3H]-labeled VLDL secretion in the presence of nonlabeled stearate (12.8±0.7 pmol/mg protein/4h) was 46, 59, and 22% of that
observed for those treated with myristate, palmitate, and oleate, respectively. [1-14C]Stearate as a substrate was also less effective than other labeled fatty acids to be incorporated into VLDL lipids. Of total
VLDL lipids synthesized from [1-14C] stearate, triacylglycerol accounted for 78% as compared to 88–97% of that derived from palmitate, myristate, and oleate.
The amounts of apoB100 and apoB48 were the same in hepatocytes treated with or without exogenous fatty acids. Similarly, the
rate of apoB synthesis from [35S] methionine was not affected by exogenous fatty acids. The treatment of cells with various saturated fatty acids increased
the particle size of VLDL to different extents. The largest particles of VLDL, with a mean diameter of 79.3±11.9 nm, were
seen in the cells treated with stearate, followed by those treated with palmitate and myristate (45.5±9.8 and 38.6±6.8 nm,
diameter, respectively). Clearly, hepatocytes treated with stearate secrete less VLDL and produce larger VLDL particles than
those treated with shorter-chain saturated fatty acids. 相似文献
14.
The lipid concentration and fatty acid composition of the whole liver and of cultured hepatocytes isolated from the livers
of rats fed ad libitum (fed), fasted for 24 hr (fasted), or fasted for 48 hr and then refed a fat-free, high carbohydrate
diet for 48 hr (refed) was studied. Hepatocytes were maintained as monolayer cultures in serum-free, lipid-free media and
their fatty acid composition was analyzed at 3, 24, 48, 72 and 96 hr. The livers of fed animals, as well as their hepatocytes,
contained less total lipid than those from animals on either of the other dietary regimes. Livers of fasted animals had three
times the amount of lipid found in the livers of fed animals, and the livers of refed animals contained five times the amount
of lipid as the livers of fed animals (all based on mg lipid/g wet weight of liver). The fatty acid composition of hepatocytes
after 3 hr of culturing was very similar to that of fresh liver when compared in each of the dietary regimes. However, while
the fatty acid compositions of livers and hepatocytes from fed and fasted animals were similar, the pattern in liver of refed
animals was quite distinct from that of the fed animals. In the fed and fasted animals palmitic acid (16∶0), stearic acid
(18∶0), oleic acid (18∶1[n-9]), linoleic acid (18∶2[n-6]) and arachidonic acid (20∶4[n-6]) were the major fatty acids of the
liver; in refed animals 16∶0, palmitoleic acid (16∶1[n-7]), 18∶0, 18∶1(n-9) andcis-vaccenic acid (the n-7 isomer of oleic acid) were the major fatty acids. During maintenance in culture the 18∶1(n-9) content
of the hepatocytes increased in cells from livers of animals on all three dietary regimes. The polyunsaturated fatty acid
content was similar in fresh livers and isolated hepatocytes in all samples when compared on the basis of μg fatty acid/mg
of hepatocyte or liver protein. It was also found that the polyunsaturated fatty acid content of hepatocytes was remarkedly
stable with time of culture when the cells were incubated in serum-free, lipid-free medium. Thus, isolated hepatocytes maintained
in serum-free medium appear to be a possible system for the evaluation of the effects of prior nutritional status on fatty
acid metabolism in the whole animal, not subject to hormonal and other somatic influences which often complicate the interpretation
of such nutritional studies. 相似文献
15.
This study examined the effect on the plasma lipids and plasma phospholipid and cholesteryl ester fatty acids of changing
from a typical western diet to a very low fat (VLF) vegetarian diet containing one egg/day. The effect of the addition of
saturated, monounsaturated or polyunsaturated fat (PUFA) to the VLF diet was also examined. Three groups of 10 subjects (6
women, 4 men) were fed the VLF diet (10% energy as fat) for two weeks, and then in the next two weeks the dietary fat in each
group was increased by 10% energy/week using butter, olive oil or safflower oil. The fat replaced dietary carbohydrate. The
VLF diet reduced both the low density lipoprotein (LDL)-and high density lipoprotein (HDL)-cholesterol levels; addition of
the monounsaturated fats and PUFA increased the HDL-cholesterol levels, whereas butter increased the cholesterol levels in
both the LDL- and HDL-fractions. The VLF diet led to significant reductions in the proportion of linoleic acid (18∶2ω6) and
eicosapentaenoic acid (20∶5ω3) and to increases in palmitoleic (16∶1), eicosatrienoic (20∶3ω6) and arachidonic acids (20∶4ω6)
in both phospholipids and cholesteryl esters. Addition of butter reversed the changes seen on the VLF diet, with the exception
of 16∶1, which remained elevated. Addition of olive oil resulted in a significant rise in the proportion of 18∶1 and significant
decreases in all ω3 PUFA except 22∶6 compared with the usual diet. The addition of safflower oil resulted in significant increases
in 18∶2 and 20∶4ω6 and significant decreases in 18∶1, 20∶5ω3 and 22∶5ω3. These results indicate that the reduction of saturated
fat content of the diet (<6% dietary energy), either by reducing the total fat content of the diet or by exchanging saturated
fat with unsaturated fat, reduced the total plasma cholesterol levels by approximately 12% in normocholesterolemic subjects.
Although the VLF vegetarian diet reduced both LDL- and HDL-cholesterol levels, the long-term effects of VLF diets are unlikely
to be deteterious since populations which habitually consume these diets have low rates of coronary heart disease. The addition
of safflower oil or olive oil to a VLF diet produced favorable changes in the lipoprotein lipid profile compared with the
addition of butter. The VLF diets and diets rich in butter, olive oil or safflower oil had different effects on the 20 carbon
eicosanoid precursor fatty acids in the plasma. This suggests that advice on plasma lipid lowering should also take into account
the effect of the diet on the fatty acid profile of the plasma lipids. 相似文献
16.
Hiromi Kimoto Yasushi Endo Kenshiro Fujimoto 《Journal of the American Oil Chemists' Society》1994,71(5):469-473
To understand the relationship between triacylglycerol structure of marine oils and their oxidative stability, peroxide values
and absorbed oxygen levels of whale, sardine, cod liver and skipjack oils, interesterified by lipase and NaOCH3, were compared with those of native oils during storage at 40°C. Triacylglycerol structures of marine oils were characterized
by high-performance liquid chromatography and differential scanning calorimetry analyses. Enzymatically interesterified fish
oils were more stable than native oils because the level of highly unsaturated triacylglycerols was decreased. However, the
oxidative stability of interesterified whale oil was more susceptible to oxidation than the native oil. 相似文献
17.
Stefania Vichi Lorena Pizzale Lanfranco S. Conte 《European Journal of Lipid Science and Technology》2007,109(1):72-78
The positional distribution of fatty acids (FA) in triacylglycerols (TAG) of 47 virgin olive oils from diverse cultivars grown in distinct areas of North‐Eastern Italy was studied. Few data were previously available on oils from these geographical areas. The effects of climatic and geographical conditions on the stereospecific distribution of TAG in olive oil were confirmed. Moreover, the results of the stereospecific analysis were used to evaluate the preferential esterification position of each FA on the basis of the degree of unsaturation and the chain length. The data of the stereospecific analysis of olive oil TAG can contribute to the determination of the selectivity of olive fruit acyltransferases for distinct FA. 相似文献
18.
The in vivo synthesis of rat plasma lipoproteins was studied by the use of isotopic protein and lipid precursors. Labelled
amino acids, palmitic acid and tripalmitin were administered by stomach tube and the radioactivity in the plasma lipoproteins
was determined following preparative ultracentrifugal isolation at densities of 1.006, 1.019, 1.063 and 1.21 g/ml.
In response to triglyceride feeding, amino acid composition of the high density lipoprotein changed little, but in the low
density lipoproteins proportionality in the amino acid pattern was changed as reflected by increases and decreases in certain
amino acids.
Isotopic amino acids were not incorporated in proportion to the relative abundance with which they occurred in the lipoproteins.
Triglyceride feeding markedly stimulated isotope utilization, especially in the low density fractions. Methionine, though
only present in small amounts, was extensively utilized and it is suggested that this amino acid may play a significant role
in the synthesis of lipoproteins, other than the role of a methyl donor for phosphatidylcholine. 相似文献
19.
Six oils of marine, algal, and microbial origin were analyzed for stereospecific distribution of component fatty acids. The
general procedure involved preparation ofsn-1,2-(2,3)-diacylglycerols by partial deacylation with ethylmagnesium bromide or pancreatic lipase, separation of X-1,3- andsn-1,2(2,3)-diacylglycerols by borate thin-layer chromatography, resolution of thesn-1,2- andsn-2,3-enantiomers by chiral phase high-performance liquid chromatography following preparation of dinitrophenylurethane derivatives,
and determination of the fatty acid composition by gas chromatography. Unexpected complications arose during a stereospecific
analysis of triacylglycerols containing over 33% of either 20∶4 or 22∶6 fatty acids. Thesn-1,2(2,3)-diacylglycerols made up of two long-chain polyunsaturated acids migrated with the X-1,3-diacylglycerols and required
separate chiral phase resolution. Furthermore, the enzymatic method yieldedsn-1,2(2,3)-diacylglycerols, overrepresenting the polyenoic species due to their relative resistance to lipolysis, but prolonged
digestion yielded correct composition for the 2-monoacylglycerols. The final positional distribution of the fatty acids was
established by pooling and normalizing the data from subfractions obtained by norman- and chiral-phase separation of diacylglycerols.
The molecular species of X-1,3-,sn-1,2- andsn-2,3-diacylglycerol dinitrophenylurethanes were identified by chiral-phase liquid chromatography/mass spectrometry with electrospray
ionization, which demonstrated a preferential association of the paired long-chain acids with thesn-1,2- andsn-2,3-diacylglycerol isomers. 相似文献
20.
T. L. Mounts K. Warner G. R. List R. Kleiman W. R. Fehr E. G. Hammond J. R. Wilcox 《Journal of the American Oil Chemists' Society》1988,65(4):624-628
During the last 15 years, hybridization and induced mutation breeding of soybeans have been successful in producing an altered
fatty acid composition in the extracted oil. The objective of those investigations was to produce a low-linolenic acid soybena
oil. Crude oils extracted from the seeds of three such genotypes were processed in laboratory simulations of commercial procedures
to finished deodorized oils. Analysis of the fatty acid composition of the three oils showed the linolenic acid content to
be 3.3%, 4.2% and 4.8%. The stability of these finished oils was compared to that of oil from a soybean variety having a linolenic
acid content of 7.7% and of a commercial hydrogenated-winterized soybean oil (3.0% linolenic acid). Test and control oils
were evaluated by a trained sensory panel initially, after accelerated storage at 60 C and during use at 190 C in room tests.
Peroxide values were determined at the time of sensory evaluation. Results indicated there was no significant difference in
flavor stability during storage between test and control oils. There was no significant difference, between the oils, in peroxide
development during accelerated storage. Compared to control oils, the test oils had improved overall room odor intensity scores
and lacked the fishy odors of non-hydrogenated soybean oil and the hydrogenated odors of commercial cooking oil.
Presented at the AOCS meeting in Honolulu, HI in May 1986. 相似文献