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1.
Menhaden oil (MO), whose polyunsaturated fatty acids consist mainly of (n−3) fatty acids, was fed to spontaneously hypertensive
rats to determine the effect of (n−3) fatty acid on the in vitro production of prostaglandins produced from arachidonic acid
(20∶4[n−6]). Capacity to form PGE2 and PGF2α was impaired in homogenates of kidney medullae and cortices from rats fed the MO diet compared to rats fed the control diet.
The lower amounts of diene prostaglandins produced corresponded to the decrease in the amount of 20∶4 (n−6) in the tissue.
Possibly changes produced in tissue lipids by dietary fatty acids affect prostaglandin production by reducing the availability
of substrate in tissue lipids. 相似文献
2.
The effect of dietary n−3 fatty acids on prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) levels in rat salivary glands and gingiva was examined in two separate nutritional studies. In the first set of experiments,
two groups of male weanling Sprague-Dawley rats were fed semipurified diets containing 10% corn oil (control group) or 10%
menhaden oil (experimental group). Rats were killed after 8 wk on the diets; the fatty acid composition of total phospholipids
and the concentrations of PGE2 and its precursor, arachidonic acid, were measured in gingiva and submandibular salivary glands (SMSG). Dietary n−3 fatty
acids were incorporated into the tissue phospholipids. Arachidonic acid levels were reduced by 56% in gingiva and SMSG of
rats fed menhaden oil compared with the control rats fed the diet containing corn oil. The concentrations of PGE2 in SMSG and gingiva of rats fed the diet containing menhaden oil were reduced by 74% and 83%, respectively. In a subsequent
nutritional study, we tested whether the diet-induced reduction in tissue arachidonic acid levels would also result in a corresponding
decrease in LTC4 production. Three groups of rats were fed diets containing 5% corn oil (group 1), 4% ethyl ester concentrate of n−3 fatty
acids plus 1% corn oil (group 2), or 5% ethyl ester concentrate of n−3 fatty acids (group 3). After 6 wk of feeding, gingiva
and SMSG were analyzed for arachidonic acid content andin vitro production of LTC4. Arachidonic acid content of total phospholipids was about 60% lower in gingiva and 69% lower in SMSG of rats fed the ethyl
ester concentrate of n−3 fatty acids (groups 2 and 3) than those of the control group fed the corn oil diet (group 1). Upon
incubation with calcium ionophore, gingiva and SMSG from rats fed the n−3 fatty acids rich diet produced significantly less
TLC4 than those from rats of the control group. Because PGE2 and LTC4 are believed to be important biochemical mediators of periodontal disease, one may speculate that a diet-induced reduction
in their levels may have a beneficial effect upon the course of the disease. The function of salivary glands may also be altered
because of the role of these eicosanoids in salivary secretions.
Presented in part for the Hatton Award Competition at the American Association for Dental Research Meeting, San Francisco,
California, March 15–19, 1989, and at the International Association for Dental Research Meeting, Acapulco, Mexico, April 17–21,
1991. 相似文献
3.
E. J. V. J. Christ 《European Journal of Lipid Science and Technology》1970,72(10):849-853
The Role of Prostaglandins in Hormone-Stimulated Lipolysis in Isolated Fatty Tissues Biosynthesis of PGE from 14C labelled unsaturated fatty acids by enzyme preparations from epididymal fatty tissues of rats and rams is reported. Di-homo-γ-linolenic acid and arachidonic acid were detected in di- and triglyceride fractions of the fatty tissues of rats. The amounts found are perhaps sufficient for explaining quantitatively the synthesis of PGE in intact fatty tissues. The specificity of anti-lipolytic action of PGE homologues was studied. Prostaglandins from EFA-active fatty acids with 20 and 21 C-atoms are as active as PGE1, whereas prostaglandins from EFA-inactive fatty acids are much less active. The possible action of PGE1 on the formation and degradation of cyclic adenosine-3′,5′-monophosphate was studied with isolated enzyme system. A direct action of PGE1 could not be detected. 相似文献
4.
Effects of polyunsaturated fatty acids on expression of early-response genesc-fos and Egr-1 and induction of cell growth were assessed in Swiss 3T3 fibroblasts. Stimulation with arachidonic acid increased
mRNA levels ofc-fos and Egr-1. This effect was inhibited by preincubation with cyclooxygenase inhibitors and restored by addition of prostaglandin
E2 (PGE2), the predominant eicosanoid produced in Swiss 3T3 fibroblasts. Further signaling of PGE2 was mediated by a protein kinase C-dependent pathway, since downregulation, or inhibition, of protein kinase C reduced increases
in mRNA levels. Parallel to the stimulatory effects on mRNA levels, AA and PGE2 also increased cell growth, as determined by uptake of [3H]-thymidine. In contrast to arachidonic acid, n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
did not increasec-fos and Egr-1 mRNA levels or cell growth. Furthermore, preliminary data indicate that EPA and DHA even reduce the stimulatory
effect of AA, which is associated with reduced formation of PGE2. In conclusion, our data indicate that AA increases expression of growth-related early genesc-fos and Egr-1 in Swiss 3T3 fibroblasts by its conversion to PGE2 and subsequent activation of protein kinase C, whereas n-3 fatty acids do not activate this signaling cascade. 相似文献
5.
Mapping the Binding Sites of UDP and Prostaglandin E2 Glyceryl Ester in the Nucleotide Receptor P2Y6
Anne Zimmermann Dr. Oanh Vu Dr. Antje Brüser Dr. Gregory Sliwoski Prof. Dr. Lawrence J. Marnett Prof. Dr. Jens Meiler Prof. Dr. Torsten Schöneberg 《ChemMedChem》2022,17(7):e202100683
Cyclooxygenase-2 catalyzes the biosynthesis of prostaglandins from arachidonic acid and the biosynthesis of prostaglandin glycerol esters (PG-Gs) from 2-arachidonoylglycerol. PG-Gs are mediators of several biological actions such as macrophage activation, hyperalgesia, synaptic plasticity, and intraocular pressure. Recently, the human UDP receptor P2Y6 was identified as a target for the prostaglandin E2 glycerol ester (PGE2-G). Here, we show that UDP and PGE2-G are evolutionary conserved endogenous agonists at vertebrate P2Y6 orthologs. Using sequence comparison of P2Y6 orthologs, homology modeling, and ligand docking studies, we proposed several receptor positions participating in agonist binding. Site-directed mutagenesis and functional analysis of these P2Y6 mutants revealed that both UDP and PGE2-G share in parts one ligand-binding site. Thus, the convergent signaling of these two chemically very different agonists has already been manifested in the evolutionary design of the ligand-binding pocket. 相似文献
6.
Three groups of male mice were fed a normal diet or a semisynthetic diet containing either 10% hydrogenated coconut oil (CO
group) or 10% menhaden oil (MO group) for two wk. The synthetic diet altered the fatty acid composition of lung microsomal
lipids. Mice ingesting menhaden oil contained greater amounts of eicosapentaenoic acid (20∶5 n−3), docosapentaenoic acid (22∶5
n−3) and docosahexaenoic acids (22∶6 n−3) and decreased amounts of n−6 fatty acids such as arachidonic and adrenic. Synthesis
of prostaglandin E2 and prostaglandin F2α from exogenous arachidonic acid was significantly depressed in n−3 fatty acid-enriched lung microsomes. These studies indicated
that dietary fish oil not only alters the fatty acid composition of lung microsomes but also lowers the capacity of lungs
to synthesize prostaglandins from arachidonic acid. 相似文献
7.
Studies are reported on the detection and in vitro biosynthesis of prostaglandins of the E type in the tail skin of male Sprague-Dawley
rats. It was found that strips of skin were preferred to other techniques of skin preparations, such as mincing or homogenization
for the assay of endogenous prostaglandins. Each strip of tail skin could be used at least twice, each time in fresh buffer
to obtain additional release of endogenous prostaglandins. The skin was stripped from a longitudinal incision in the tail
in one piece and cut into four parallel strips lengthwise. Each strip of skin was incubated singly and the prostaglandins
were extracted with ethyl acetate. The detection and analysis of prostaglandins of the E type were carried out by standard
procedures on the residue of this extract dissolved in 95% ethanol. By means of this technique, endogenous prostaglandins
were detected in the tail skin of rats. Little or no prostaglandins were extracted by organic solvents directly from the tissue,
and the yields were low when the tissue was minced. The results indicate the possibility that endogenous prostaglandins may
be synthesized during incubation in buffer or may be released from binding with other cellular components. The major prostaglandin
of this tissue was PGE2; prostaglandin E1 (PGE1) was also detected. Using the same procedure, the presence of a prostaglandin synthetase system in the tail skin was demonstrated
by the conversion of exogenous arachidonic acid to prostaglandin E2 (PGE2). 相似文献
8.
Renée Grataroli Jeannie Léonardi Monique Charbonnier Raymond Lafont Huguette Lafont Gilles Nalbone 《Lipids》1988,23(7):666-670
Three groups of male rats were fed either a corn oilenriched diet (17%, w/w), a salmon oil-enriched diet (12.5%) supplemented
with corn oil (4.5%) or a low-fat diet (4.4%) for eight wk to investigate the possible relationships between dietary fatty
acids and lipid composition, and prostaglandin E2 level and phospholipase A2 activity in the rat gastric mucosa.
High-fat diets induced no important variation in total protein, phospholipid and cholesterol contents of gastric mucosa.
Compared with a low-fat diet, corn oil produced a higher n−6/n−3 ratio in mucosal lipids, whereas this ratio was markedly
lowered by a fish oil diet.
In comparison with the low-fat diet, the production of prostaglandin E2(PGE2) in gastric mucosa of rats fed salmon oil was significantly, decreased by a factor of 2.8. In the corn oil group, PGE2 production tended to decrease, but not significantly.
In comparison with the low-fat diet, both specific and total gastric mucosal phospholipase A2 activities were increased (+18 and 23%, respectively) in the salmon oil group; they were unchanged in the corn oil group.
It is suggested that the decrease of gastric PGE2 in rats fed fish oil is not provoked by a decrease in phospholipase A2 activity but may be the result of the substitution of arachidonic acid by n−3 PUFA or activation of PGE2 catabolism. 相似文献
9.
The biological activity, including metabolism and modulation of ornithine decarboxylase activity and DNA synthesis, of arachidonic
acid (AA) and eicosapentaenoic acid (EPA) were compared in epidermal cells from SENCAR mice. Radiolabelled AA and EPA were
found to be similarly incorporated into and released from membrane phospholipids of unstimulated cultures. However, when cells
were stimulated with the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA), the release of AA was significantly higher
than the release of EPA. The extent of metabolism of AA and EPA to prostaglandins was determined in both freeze-thawed cell
preparations and in viable cultured cells. In the freeze-thawed preparations, use of AA as a substrate resulted in significantly
more PGF than when EPA was used as the substrate. However, more PGE3 was formed than PGE2. PGD levels were the same for either fatty acid precursor. Prostaglandin production was also determined in viable cultured
cells since other influences such as phospholipase A2 activity can modify prostaglandin production. Control cultures prelabelled with either AA or EPA produced similar amounts
of the respective PGF, PGE, and PGD. However, TPA-stimulated cultures produced significantly higher amounts of each prostaglandin
in cultures prelabelled with AA compared to cells prelabelled with EPA. HETE or HEPE production was the same both for cultured
cells prelabelled with AA or EPA and for homogenates from uncultured cells incubated directly with the radiolabelled fatty
acids. TPA-induced ornithine decarboxylase (ODC) was significantly higher in AA-treated cultures compared to EPA-treated cultures.
AA supports DNA synthesis to a greater extent than EPA, either alone or in the presence of TPA. These findings suggest that
AA and EPA do not have equivalent biological activity in mouse epidermal cells. 相似文献
10.
Total lipids from whole pig adrenal glands as well as from their mitochondria, microsomes, liposomes, and cell sap were extracted and fractionated first into neutral lipids and phospholipids. The highest percentage of neutral lipids was found in the cell sap, and the lowest in the microsomal fraction. Neutral lipids were subfractionated into cholesteryl esters, free cholesterol, triglycerides, and free fatty acids. Cholesteryl esters were distributed throughout the liposomes. Free fatty acids represented a substantial part of cell sap lipids, but were present also in the mitochondria, microsomes, and liposomes. Fatty acids of all fractions were analyzed by gas liquid chromatography. Free fatty acids and cholesteryl ester fatty acids from all cellular fractions were similar in composition and were characterized by considerable quantities of linoleic and arachidonic acid. Triglycerides were characterized by an increased percentage of palmitic and a low content of arachidonic acid. Phosphatidyl choline, phosphatidyl ethanolamine, diphosphatidyl glycerol, and sphingomyelin plus phosphatidyl inositol were isolated from the lipids by preparative thin layer chromatography, and their fatty acids analyzed by gas liquid chromatography. Phosphatidyl choline and phosphatidyl ethanolamine from mitochondria, microsomes, and cell sap were very similar in respect of their fatty acid composition. Sphingomyelin plus phosphatidyl inositol was characterized by a high content of C22:2omega6. Diphosphatidyl glycerol was present in mitochondria and in the cell sap. 相似文献
11.
Techniques are described whereby problems in the analysis of endogenous prostaglandins in rat vesicular glands are obviated
by the use of powdered glands prepared by grinding the tissues in the frozen state. Freshly excised glands were cut into small
pieces, frozen on dry ice and then pulverized to a fine powder. These powders were used as such or extracted with acetone.
In the latter technique, the endogenous prostaglandins were quantitatively extracted into acetone, and most of the biological
activity for prostaglandin synthesis was retained in the residual cake. Application of the techniques showed that the E2 form was the major prostaglandin of the E series in rat vesicular glands. 相似文献
12.
David G. Cornwell James J. Huttner George E. Milo R. V. Panganamala H. M. Sharma Jack C. Geer 《Lipids》1979,14(2):194-207
Smooth muscle cell cultures were obtained from the aortas of prepubertal guinea pigs. Cell proliferation in these cultures
was inhibited by 8,11,14-eicosatrienoic acid, 5,8,11,14-eicosatetraenoic acid, and their prostaglandin E derivatives, PGE1 and PGE2. Prostaglandin F derivatives, PGF1α and PGF2α, stimulated cell proliferation. Cell proliferation was also inhibited by 5,8,11-eicosatrienoic acid and 11,14,17-eicosatrienoic
acid. The monoene and diene precursors of the triene acids, 9-octadecenoic acid and 9,12-octadecadienoic acid, did not inhibit
cell, proliferation. Indomethacin alone had no effect on cell proliferation, and indomethacin did not suppress the inhibition
of cell proliferation with a triene acid. The antioxidant α-naphthol alone stimulated cell proliferation and suppressed prostaglandin
E formation. α-Naphthol in the presence of either triene or tetraene acids also stimulated cell proliferation and suppressed
prostaglandin E formation. The antioxidants butylated hydroxy toluene and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic
acid either alone or in the presence of triene and tetraene acids stimulated cell proliferation and had no effect on prostaglandin
E formation. Vitamin E either alone or in the presence of triene or tetraene acids stimulated cell proliferation and had no
effect on prostaglandin E formation. More prostaglandin E was formed from 8,11,14-eicosatrienoic acid than from 5,8,11,14-eicosatetraenoic
acid in the presence of antioxidants. Vitamin E suppressed the inhibitory effects of both PGE2 and palmitic acid on cell proliferation. The cyclic nucleotide phosphodiesterase inhibitors, caffeine and papaverine, suppressed
the stimulatory effect of vitamin E on cell proliferation and enhanced the inhibitory effect of a triene acid on cell proliferation.
Substrate and inhibitor specificities are consistent with the oxidative regulation of cell proliferation through the formation
of hydroperoxy fatty acids. We propose that hydroperoxy fatty acids may regulate both cyclase and cyclic nucleotide phosphodiesterase
enzymes through sulfhydryl-disulfide interconversions. We suggest that this regulatory mechanism may help to explain the acculation
of 5,8,11-eicosatrienoic acid in essential fatty acid deficiency, the effects of antioxidants on cell proliferation, and one
of the several effects of polyunsaturated fatty acids in proliferative disorders such as cancer and atherosclerosis. 相似文献
13.
Skin surface lipids of the dog 总被引:1,自引:0,他引:1
The skin surface lipid of the dog has been reported to contain a high proportion of diol diesters having a lower mobility
on thin layer chromatography than diesters from other species in spite of containing similar fatty acid and diol components.
In the present study, dog skin surface lipid was separated by preparative thin layer chromatography into sterol esters (42%),
wax diesters (32%), free sterols (9%), polar lipids (7%), and unidentified components (10%). The diesters contained 1,2-diols,
each esterified with one long chain fatty acid and one isovaleric acid moiety. The diols were principally branched chain C21 and C22 compounds while the long chain fatty acids esterified with them were mainly C20 and C21 branched compounds. The fatty acids from the sterol esters were mostly saturated, branched chain C19 to C23, together with 7% of straight chain monoenoic acids, principally C21 and C22. There were only trace amounts of free sterols other than cholesterol, while the esterified sterols contained 96% cholesterol
and 4% lathosterol. 相似文献
14.
Three groups of weanling male rats were fed on a fat-free diet for 13 weeks. One group received only the fat-free diet (FF
rats), the other 2 groups received the fat-free diet and a daily supplement of 2 energy% ethyl linoleate ([n−6] rats), or
2 energy% ethyl linolenate ([n−3] rats). Urinary excretion of prostaglandin E2 (PGE2), immunoreactive arginine vasopressin (iA VP), and kallikrein were determined. PGE2 was quantitated with a radioimmunoassay having 4.9% cross-reactivity with prostaglandin E3 (PGE3). After 4 weeks on the diet, water consumption and urinary iAVP excretion increased significantly in the FF rats and the
(n−3) rats compared with the (n−6) rats. Urinary PGE2 excretion was the same for all 3 groups during the first 10 weeks; thereafter it decreased in FF rats and (n−3) rats compared
with the (n−6) rats. There was no difference in urinary PGE2 excretion between the FF rats and the (n−3) rats, even though large differences were found in the percentage of arachidonic
acid (20∶4[n−6]), icosapentaenoic acid (20∶5[n−3]), and icosatrienoic acid (20∶3[n−9]) of total kidney fatty acids as well
as of kidney phosphatidylinositol fatty acids. Fractionation of urine extracts on high performance liquid chromatography with
radioimmunoassay detection indicated that (n−3) rats excreted very little PGE3, if any. Urine output followed the same pattern, as did urinary PGE2 excretion. Urinary kallikrein was estimated at week 12 only. It was found to be significantly lower in FF rats and (n−3)
rats. Increased water consumption and increased urinary iAVP excretion seem to be early symptoms (after 4 weeks) of EFA deficiency,
whereas decreased urine output and decreased urinary PGE2 excretion occur much later (after 10 weeks). Two energy% linolenate supplementation to a fat-free diet did not change the
appearance of any of the measured EFA-deficiency symptoms except for a slightly improved growth rate. There was no evidence
of a significant urinary PGE3 excretion in spite of an extreme enrichment of kidney lipids with 20∶5(n−3). It is suggested that urinary PGE2 is derived from precursors delivered from an arachidonic acid pool, which is rather resistant to restriction in dietary linoleate.
Presented in part at the 23rd International Conference on Biochemistry of Lipids, Nyborg, Denmark, August 1981, and at the
Vth International Conference on Prostaglandins, Florence, Italy, May 1982. 相似文献
15.
A study was made with sheep on the formation in vitro of long chain fatty acid esters of cholesterol by the lecithin-cholesterol-acyltransferase
system present in the plasma and the acyl CoA-cholesterol-acyltransferase system present in the liver. The rate of cholesterol
esterification in the plasma was 0.024 μmoles/ml/hr. The relative pattern of fatty acids esterified during incubation of the
plasma remained constant over the 8 hr period of incubation and was similar to the fatty acids in the plasma cholesteryl esters
before incubation began and to the fatty acids in the 2-position of the plasma lecithin. The predominant cholesteryl esters
synthesized contained monoenoic and dienoic fatty acids. Unlike the bovine, there was no apparent discrimination in favor
of the 18∶2 containing species of plasma lecithin as donors of fatty acids. This difference could be accounted for by the
similarity in the 18∶2 content of the phospholipids present in the high density (density >1.062 and < 1.21) and the low density
(density > 1.006 and <1.063) lipoprotein fractions of the sheep plasma. The possibility of some discrimination against 20∶4
during cholesterol ester synthesis in the plasma of the sheep cannot be excluded. In the liver, the predominant cholesteryl
esters synthesized contained saturated and monoenoic fatty acids; cholesteryl linoleate was synthesized to a very much less
extent. There was considerable similarity between the composition of the unesterified fatty acid fraction of the liver before
incubation began and the fatty acid composition of the cholesteryl esters synthesized during incubation. Addition of sonicated
suspensions of free fatty acids altered markedly the fatty acid pattern of the cholesteryl esters synthesized by the liver
slices. From the evidence presented it is concluded that the cholesteryl esters in sheep plasma are syntheized mainly by the
plasma lecithin-cholesterol-acyltransferase system. The results are discussed in relation to cholesterol esterification systems
demonstrated in the plasma and liver of monogastric animals. 相似文献
16.
The fatty acid composition and metabolic activity of cholesterol esters in milk and mammary tissue (cow, sow and goat) were
investigated. Cholesterol esters of freshly secreted milks incubated at 40 C for 2 hr showed no change in fatty acid composition
and no incorporation of 1-14C-palmitate. The fatty acid composition of cholesterol esters in the milk of all three species exhibited elevated levels of
a unique group of fatty acids when compared to other milk ester lipid classes. This group was comprised of monounsaturated
acids and acids with odd numbers of carbons. Tissue cholesterol esters contained lower levels of these acids. Evidence from
experiments in which an odd carbon acid (C15) was infused into the lactating mammary gland indicated that the group of unique acids is preferentially retained in the
cholesterol ester fraction which is secreted with milk. These infusion experiments also provided evidence that cholesterol
esters accumulate in developing milk fat globules in a manner paralleling triglyceride accumulation, and that acyl moieties
of cholesterol esters may be desaturated in the form of the intact ester. Our results are compatible with the hypothesis that
acyl moieties of cholesterol esters in lactating mammary tissue are turning over rapidly.
Paper No. 3496 in the journal series of the Pennsylvania Agricultural Experiment Station. 相似文献
17.
The relationship between polyunsaturated long-chain fatty acids and atopy has been discussed for decades. Higher levels of
the essential fatty acids linoleic acid and α-linolenic acid and lower levels of their longer metabolites in plasma phospholipids
of atopic as compared to nonatopic individuals have been reported by several, but not all, studies. Largely similar findings
have been reported in studies of cell membranes from immunological cells from atopics and nonatopics despite differences in
methodology, study groups, and definitions of atopy. An imbalance in the metabolism of the n−6 fatty acids, particularly arachidonic
acid and dihomo-γ-linolenic acid, leading to an inappropriate synthesis of prostaglandin (PG) E2 and PGE1 was hypothesized early on but has not been corroborated. The fatty acid composition of human milk is dependent on the time
of lactation not only during a breast meal but also the time of the day and the period of lactation. This explains the discrepancies
in reported findings regarding the relationship between milk fatty acids and atopic disease in the mother. Prospective studies
show disturbances in both the n−6 and n−3 fatty acid composition between milk from atopic and nonatopic mothers. Only the
composition of long-chain polyunsaturated n−3 fatty acids was related to atopic development in the children, however. A relationship
between lower levels of n−3 fatty acids, particularly eicosapentaenoic acid (20∶5 n−3), and early development of atopic disease
is hypothesized. 相似文献
18.
Studies from this laboratory, employing a hairless mouse model, have indicated that a polyunsaturated fatty acid source rich
in omega-3 (n−3) fatty acid (FA) inhibits ultraviolet (UV)-carcinogenic expression, when compared to that of diets containing
predominantly n−6 fatty acids. Omega-3 FA is a poor substrate for cyclo-oxygenase, the rate-limiting step in prostaglandin
(PG) synthesis—the latter, particularly PGE2, are known to influence tumor biology. Based upon this rationale, plasma and cutaneous PGE2 levels were determined from hairless mice fed diets containing either 4% or 12% corn or menhaden oil. After two weeks on
the respective diets, plasma PGE2 levels of corn oil-fed animals were approximately 6-fold greater than those of the menhaden oil-fed groups. A similar response
was found in the dermis. Although the relationship to carcinogenic expression is unknown, dietary n−3 FA content can have
a pronounced effect upon PGE2 levels and possesses the potential for influencing other immunomodulators. 相似文献
19.
J. J. Ellington P. F. Schlotzhauer A. I. Schepartz 《Journal of the American Oil Chemists' Society》1978,55(7):572-573
Flue-cured tobacco was subjected to alkaline hydrolysis, and, after acidification, the fatty acids and nonsaponifiables were
extracted into hexane. Treatment of the hexane extract with diazomethane yielded fatty acid methyl esters. The methyl esters
were separated from interfering hydrocarbons and sterols by preparative thin layer chromatography (PTLC). After addition of
an internal standard, the esters were quantitated by gas chromatography on the column packing, Silar 10C. Quantitation of
the C14-C32 fatty acid esters was possible by means of temperature programming. 相似文献
20.
The efficacy of individual ω-t-3 polyunsaturated fatty acids (PUFA) in altering eicosanoid synthesis in peritoneal macrophages
was studied by feeding mice for 10 days a diet containing 2 wt% fat, which included 0.5 wt% ethyl esters of eicosapentaenoic
acid (EPA), docosahexaenoic acid (DHA) or linolenic acid (LNA). Upon stimulation with calcium ionophore A23187, macrophages
from these animals produced significantly lower amounts of leukotriene C4, leukotriene B4 and 12-hydroxyeicosatetraenoic acid, prostaglandin E2 and 6-keto prostaglandin F1α compared with those obtained from animals on the diets containing olive oil or safflower oil. The decrease in leukotriene
synthesis was similar in the animals fed DHA, EPA or LNA diets. This depression of eicosanoids by DHA and EPA was associated
with decreased levels of arachidonic acid (AA); however, LA that altered eicosanoids did not have the same effect on AA levels. 相似文献