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1.
The effects of antibodies against microsomal electron-transport components on the in vitro activity of Δ6-desaturation of linoleic acid to γ-linolenic acid have been studied in intact microsomal membranes of rat liver. Reduced
nicotinamide adenine dinucleotide (NADH) or reduced nicotinamide adenine dinucleotide phosphate (NADPH) (0.87 mM) served as
electron donors, and effectively prompted the Δ6-desaturase activities with yields of about 1.1 to 1.3 nmol per mg of protein in 10 min. Of the two antibodies studied under
the same in vitro conditions, i.e., rabbit antisera preparations against rat liver microsomal hydrophilic parts of cytochrome
b5 and NADPH-cytochrome c reductase, only the antibody against cytochrome b5 demonstrated a marked ability to inhibit the Δ6-desaturase activity. This evidence supports a participation of cytochrome b5 in the Δ6-desaturation of linoleic acid and suggests a pathway analogous to the Δ9-desaturation of stearyl-CoA. 相似文献
2.
Cloning of Δ12- and Δ6-desaturases from Mortierella alpina and recombinant production of γ-linolenic acid in Saccharomyces cerevisiae 总被引:2,自引:0,他引:2
Yung-Sheng Huang Sunita Chaudhary Jennifer M. Thurmond Emil G. Bobik Jr. Ling Yuan George M. Chan Stephen J. Kirchner Pradip Mukerji Deborah S. Knutzon 《Lipids》1999,34(7):649-659
Two cDNA clones with homology to known desaturase genes were isolated from the fungus Mortierella alpina. The open reading frame in one clone encoded 399 amino acids and exhibited Δ12-desaturase activity when expressed in Saccharomyces cerevisiae in the presence of endogenous fatty acid substrate oleic acid. The insert in another clone contained an open reading frame
encoding 457 amino acids and exhibited Δ6-desaturase activity in S. cerevisiae in the presence of exogenous fatty acid substrate linoleic acid. Expression of the Δ12-desaturase gene under appropriate
media and temperature conditions led to the production of linoleic acid at levels up to 25% of the total fatty acids in yeast.
When linoleic acid was provided as an exogenous substrate to the yeast cultures expressing the Δ6-desaturase activity, the
level of γ-linolenic acid reached 10% of the total yeast fatty acids. Co-expression of both the Δ6- and Δ12-desaturase cDNA
resulted in the endogenous production of γ-linolenic acid. The yields of γ-linolenic acid reached as high as 8% of total fatty
acids in yeast. 相似文献
3.
The activity of Δ6-desaturase of linoleic acid, a rate-limiting step in the formation of arachidonic acid, is decreased in
animal models of severe, uncontrolled diabetes. The aim of the study was to measure the activity of liver microsomal Δ6-desaturase
of spontaneously diabetic BioBreeding/Edinburgh rats receiving subcutaneous insulin daily and of genetically related nondiabetic
animals. The activity of Δ6-desaturase was then compared with indices of activity (plasma lipid fatty acid product/precursor
ratios) frequently used in human studies. Diabetic rats treated with insulin had 75±8% of the activity of microsomal Δ6-desaturase
of nondiabetic controls (P<0.05). Insulin withdrawal tended to reduce the activity further (61% of control), although the activity did not differ from
insulin-treated diabetic rats. The ratio of plasma phospholipid or cholesteryl ester γ-linolenic over linoleic acid was not
decreased in insulin-treated diabetic rats. By contrast, the ratio of γ-linolenic over linoleic acid of microsomes was almost
three-fold higher in insulin-treated diabetic rats (P<0.05). The γ-linolenic over linoleic acid ratio as an index of activity gave inconsistent results in insulin-deprived rats.
The ratio of γ-linolenic over linoleic acid of cholesteryl esters did not differ between control and diabetic rats, nor did
it correlate with microsomal Δ6-desaturase activity. Furthermore, the index of Δ6-desaturase activity, derived from the fatty
acid composition of microsomal phospholipids, did not correlate with microsomal Δ6-desaturase activity. Diabetes, even when
controlled by regular insulin injections, reduces the metabolism of linoleic acid, but the effect is less than previously
published. The fatty acid compositions of plasma and liver microsomal lipids are not reliable indices of Δ6-desaturase activity
in diabetes. 相似文献
4.
The aim of the present study was to investigate the influence of partially hydrogenated vegetable and marine oils on membrane
composition and function of liver microsomes and platelets with particular reference to the metabolism of linoleic acid and
the production of arachidonic acid metabolites. Four groups of male weanling rats were fed linoleic acid supplemented diets
containing 20% (w/w) of partially hydrogenated low erucic acid rapeseed oil (HLRSO), partially hydrogenated herring oil (HHO),
olive oil (OO) and trierucin + triolein (TE) for 10 weeks. An additional two groups were fed partially hydrogenated low erucic
acid rapeseed oil and partially hydrogenated herring oil without linoleic acid supplementation (HLRSO- and HHO-, respectively).
Substantial amounts oftrans fatty acids were incorporated into liver microsomes (12.6% in group HLRSO) and platelets (7.0% in group HLRSO-). This incorporation
was not dependent on the dietary linoleic acid level. Hepatic microsomal Δ5-desaturase activity was significantly increased after HLRSO feeding compared to OO feeding. Δ6-Desaturase activity did not vary in the linoleic acid supplemented groups. Both Δ5- and Δ6-desaturase activities were significantly increased in groups without linoleic acid supplementation.
Docosenoic acid was incorporated into platelet phospholipids in contrast to liver microsomes. In the platelet, docosenoic
acid seemed to have a special preference for phosphatidylserine. Very small amounts were incorporated into platelet phosphatidylinositol.
Feeding diets HLRSO, HHO and OO did not influence rat platelet cyclooxygenase or 12-lipoxygenase activity. Platelets from
rats fed TE, however, produced significantly less 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) than platelets from
rats fed OO. Feeding of HLRSO- and HHO- resulted in a significantly diminished production of the arachidonic acid metabolites
12-HETE, 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and 6-keto-prostaglandin F1α in stimulated platelets and aorta. Thus, high dietary levels oftrans isomers of monoenoic acids do not interfere with platelet cyclooxygenase or lipoxygenase activity provided sufficient amounts
of linoleic acid are available. 相似文献
5.
José L. Periago María L. Pita María A. Sanchez del Castillo Guillermo Caamaño María D. Suárez 《Lipids》1989,24(5):383-388
Changes in fatty acid composition, microsomal Δ9- and Δ6-desaturase activities and liver contents of cholesterol and phospholipids were studied in rats fed medium chain triglyceride-supplemented
diets. Weanling rats were divided into four groups and fed for three weeks a basal diet with different 10%-fat supplements:
corn oil, medium chain triglyceride-corn oil, olive oil and medium chain triglyceride-olive oil. The highest relative content
of saturated fatty acids corresponded to corn oil-fed animals. Both monounsaturated fatty acid content and Δ9-desaturase activity were higher in the animals fed olive oil diets than in corn oil-fed rats. The long chain polyunsaturated
fatty acids of the n−3 series were increased in the olive oil and medium chain triglyceride-olive oil-fed groups probably
due to the lower linoleic/α-linolenic ratios found in these two diets. The cholesterol/phospholipid molar ratio was unaffected
by diet and the unsaturation index was only slightly changed in the four groups. Thus, some mechanism may be operative under
these conditions to maintain the homeostasis of the membrane. 相似文献
6.
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
7.
Marine fish have an absolute dietary requirement for C20 and C22 highly unsaturated fatty acids. Previous studies using cultured cell lines indicated that underlying this requirement in
marine fish was either a deficiency in fatty acyl Δ5 desaturase or C18–20 elongase activity. Recent research in turbot cells found low C18–20 elongase but high Δ5 desaturase activity. In the present study, the fatty acid desaturase/elongase pathway was investigated
in a cell line (SAF-1) from another carnivorous marine fish, sea bream. The metabolic conversions of a range of radiolabeled
polyunsaturated fatty acids that comprised the direct substrates for Δ6 desaturase ([1-14C]18∶2n−6 and [1-14C]18∶3n−3), C18–20 elongase ([U-14C]18∶4n−3), Δ5 desaturase ([1-14C]20∶3n−6 and [1-14C]20∶5n−3), and C20–22 elongase ([1-14C]20∶4n−6 and [1-14C]20∶5n−3) were utilized. The results showed that fatty acyl Δ6 desaturase in SAF-1 cells was highly active and that C18–20 elongase and C20–22 elongase activities were substantial. A deficiency in the desaturation/elongation pathway was clearly identified at the level
of the fatty acyl Δ5 desaturase, which was very low, particularly with 20∶4n−3 as substrate. In comparison, the apparent activities
of Δ6 desaturase, C18–20 elongase, and C20–22 elongase were approximately 94-, 27-, and 16-fold greater than that for Δ5 desaturase toward their respective n−3 polyunsaturated
fatty acid substrates. The evidence obtained in the SAF-1 cell line is consistent with the dietary requirement for C20 and C22 highly unsaturated fatty acids in the marine fish the sea bream, being primarily due to a deficiency in fatty acid Δ5 desaturase
activity. 相似文献
8.
Cats fed a diet containing linoleate as the only polyunsaturated fatty acid showed extremely low levels of arachidonate in
the plasma lipids, as well as an increase in linoleate, eicosadienoate and an unknown fatty acid. Administration of [1-14C] linoleic acid and [2-14C] eicosa-8,11,14-trienoic acid to cats showed that in the liver there was no conversion of the [1-14C] 18∶2 to arachidonate, whereas there was significant metabolism of [2-14C] 20∶3 to arachidonate. It was found when methyl-γ-linolenate was fed to cats that the level of 20∶3ω6 and 20∶4ω6 in the
erythrocytes increased significantly. These results show that there is no significant Δ6 desaturase activity in the cat, whereas
chain elongation and Δ5 desaturase enzymes are operative. The unknown fatty acid was isolated from the liver lipids and shown
to be a 20-carbon fatty acid with 3 double bonds and which by gas liquid chromatography could be separated from 20∶3ω9 and
20∶3ω6. The presence of the Δ5-desaturase activity and the results of the ozonolysis studies indicated that this unknown fatty
acid was eicosa-5,11,14-trienoic acid. 相似文献
9.
The specific activity of the microsomal Δ12-desaturase system, which transforms oleic acid into linoleic acid, was about 16
pmol/min/mg protein. However, most of the total activity was nonsedimentable even after a 200000×g centrifugation for 100 min. The study of various physicochemical parameters showed that this enzymatic complex, functioning
optimally between pH 7 and 8, had low thermal stability. Ca2+, which may cause an aggregation of the microsomes, and Hg2+ completely inhibited the activity, whereas Mg2+, Mn2+, and Zn2+ were activators. The Δ12-desaturase system was relatively specific toward oleic acid, though isomers of this fatty acid also
had an action, either as substrates or as competitive inhibitors, on the activity of the system. The study of the effect of
the exogenous oleoyl-CoA and elaidoyl-CoA on the specific activity of the Δ12-desaturase system showed a preference toward
oleoyl-CoA. 相似文献
10.
The Neurospora crassa cel (fatty acid chain elongation) mutant has impaired fatty acid synthase activity. The cel mutant requires exogenous 16:0 for growth and converts 16:0 to other fatty acids. In contrast to wild-type N. crassa, which converted only 42% of the exogenous [7,7,8,8-2H4]16:0 that was incorporated into cell lipids to unsaturated fatty acids, cel converted 72%. In addition, cel contains higher levels of 18:3δ9,12,15 than wild-type, and synthesizes two fatty acids, 20:2δ11,14 and 20:3δ11,14,17, found at only trace levels in wild-type. Thus, the Δ15-desaturase activity and elongation activity on 18-carbon polyunsaturated
fatty acids are higher for cel than wild-type. This altered metabolism of exogenous 16:0 may be directly due to impaired flux through the endogenous fatty
acid biosynthetic pathway, or may result from altered regulation of the synthesis of unsaturated fatty acids in the mutant. 相似文献
11.
The fatty acid composition of the seeds from Agathis robusta, an Australian gymnosperm (Araucariaceae), was determined by a combination of chromatographic and spectrometric techniques.
These enabled the identification of small amounts of arachidonic (5,8,11,14–20∶4) and eicosapentaenoic (5,8,11,14,17–20∶5)
acid for the first time in the seed oil of a higher plant. They were apparently derived from γ-linolenic (6,9,12–18∶3) and
stearidonic (6,9,12,15–18∶4) acids, which were also present, via chain elongation and desaturation, together with other expected biosynthetic intermediates [bis-homo-γ-linolenic (8,11,14–20∶3)
and bishomo-stearidonic (8,11,14,17–20∶4) acids]. Also present were a number of C20 fatty acids, known to occur in most gymnosperm families, i.e., 5,11–20∶2, 11,14–20∶2 (bishomo-linoleic), 5,11,14–20∶3 (sciadonic),
11,14,17–20∶3 (bishomo-α-linolenic), and 5,11,14,17–20∶4 (juniperonic) acids. In contrast to most other gymnosperm seed lipids
analyzed so far, A. robusta seed lipids did not contain C18 Δ5-desaturated acids [i.e., 5,9–18∶2 (taxoleic), 5,9,12–18∶3 (pinolenic), or 5,9,12,15–18∶4 (coniferonic)]. These structures
support the simultaneous existence of Δ6- and Δ5-desaturase activities in A. robusta seeds. The Δ6-ethylenic bond is apparently introduced into C18 polyunsaturated acids, whereas the Δ5-ethylenic bond is introduced into C20 polyunsaturated acids. A general metabolic pathway for the biosynthesis of unsaturated fatty acids in gymnosperm seeds is
proposed. When compared to Bryophytes, Pteridophytes (known to contain arachidonic and eicosapentaenoic acids), and species
from other gymnosperm families (without such acids), A. robusta appears as an “intermediate,” with the C18 Δ6-desaturase/C18→C20 elongase/C20 Δ5-desaturase system in common with the former subphyla, and the unsaturated C18→C20 elongase/C20 Δ5-desaturase system specific to gymnosperms. The following hypothetical evolutionary sequence for the C18 Δ6/Δ5-desaturase class in gymnosperm seeds is suggested: Δ6 (initial)→Δ6/Δ5 (intermediate)→Δ5 (final). 相似文献
12.
Fish are an important source of the n−3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic
(DHA) acids that are crucial to the health of higher vertebrates. The synthesis of HUFA involves enzyme-mediated desaturation,
and a Δ5 fatty acyl desaturase cDNA has been cloned from Atlantic salmon (Salmo salar) and functionally characterization of a Δ6 fatty acyl desaturase of Atlantic salmon and describe its genomic structure, tissue
expression, and nutritional regulation. A salmon genomic library was screened with a salmon Δ5 desaturase cDNA and positive
recombinant phage isolated and subcloned. The full-length cDNA for the putative fatty acyl desaturase was shown to comprise
2106 bp containing an open reading frame of 1365 bp specifying a protein of 454 amino acids (GenBank accession no. AY458652).
The protein sequence included three histidine boxes, two transmembrane regions, and an N-terminal cytochrome b5 domain containing the heme-binding motif HPGG, all of which are characteristic of microsomal fatty acid desaturases. Functional
expression showed that this gene possessed predominantly Δ6 desaturase activity. Screening and sequence analysis of the genomic
DNA of a single fish revealed that the Δ6 desaturase gene constituted 13 exons in 7965 bp of genomic DNA. Quantitative real-time
PCR assay of gene expression in Atlantic salmon showed that both Δ6 and Δ5 fatty acyl desaturase genes, and a fatty acyl elongase
gene, were highly expressed in intestine, liver, and brain, and less so in kidney, heart, gill, adipose tissue, muscle, and
spleen. Furthermore, expression of both Δ6 and Δ5 fatty acyl desaturase genes in intestine, liver, red muscle, and adipose
tissue was higher in salmon fed a diet containing vegetable oil than in fish fed a diet containing fish oil. 相似文献
13.
Amiram Raz Nurit Kamin-Belsky Fiorenza Przedecki Mark Obukowicz 《Journal of the American Oil Chemists' Society》1998,75(2):241-245
Liver Δ6-desaturase activity was determined in mice which were made deficient in (i) n-6 and n-3 polyunsaturated fatty acids
(PUFA), (ii) n-6 PUFA, or (iii) arachidonic acid (AA). Initially, the mice were subjected to two cycles of a fasting (1 d)/refeeding
(2–3 d) protocol in which they were refed an essential fatty acid-deficient (EFAD) diet during the refeeding period. This
1-wk fasting/refeeding protocol, referred to as F/R EFAD, produced a rapid and substantial decline in tissue n-3 and n-6 PUFA
and a corresponding increase in n-9 fatty acids, notably oleic acid and Mead acid (20:3n-9). Combined liver Δ6-desaturase/elongase/Δ5-desaturase
activities in vivo were quantified by measuring the conversion of 14C-linoleic acid (LA) to 14C-AA in mouse liver. Although F/R EFAD caused, as expected, a substantial decline in liver AA and LA content, the conversion
of 14C-LA to 14C-AA was the same in these mice as in chow-fed controls (approximately 33–34%). Subsequent refeeding of F/R EFAD mice with
an EFAD diet, supplemented with corn oil, restored tissue n-6 PUFA levels without altering the conversion of 14C-LA to 14C-AA. In contrast, refeeding with an EFAD diet, supplemented with fish oil, inhibited 14C-LA to 14C-AA conversion by 78%. Significantly, inhibition of conversion of 14C-LA to 14C-AA was maintained in F/R EFAD mice that were subsequently fed an EFAD diet supplemented with a 1:1 mixture of fish oil/corn
oil. This latter protocol yielded a unique liver fatty acid composition in which AA was selectively depleted, whereas LA and
the n-3 PUFA were increased. The data suggest that dietary n-3 C20–22 PUFA negatively regulate the in vivo synthesis of n-6 PUFA at the level of the Δ6-desaturase. 相似文献
14.
Preincubation ofTetrahymena pyriformis cells with dexamethasone inhibited the microsomal fatty acyl-CoA desaturase activities of isoproterenol-induced modulation;
that is, an increase in Δ9-desaturase activity accompanied by a decrease in Δ12-desaturase activity. Although isoproterenol caused an increase in Δ12-terminal component activity with decreased Δ12-terminal component activity, dexamethasone reduced these isoproterenol-mediated activity changes. In cells treated with dexamethasone
prior to isoproterenol administration, stimulation of cyclic AMP accumulation by isoproterenol was inhibited. These results
suggest that dexamethasone may repress isoproterenol modulation of the activity of terminal components (cyanide-sensitive
factor) in the fatty acyl-CoA desaturase system by reducing the cyclic AMP level. 相似文献
15.
Wax esters were isolated from commercial orange roughy (Hoplostethus atlanticus) oil by column chromatography and fractionated by argentation thin layer chromatography. Following transesterification, the
resultant fatty acid methyl esters and fatty alcohols were analyzed by gas chromatography. both acyl- and alkyl-moieties were
mainly of the monoene structure within the 16∶1–22∶1 range. After derivatization, the positions of the double bonds of even
numbered fatty acid and fatty alcohol isomers were located by chromatography-mass spectrometry and compared.
Results of these positional analyses indicate that the primary desaturation reactions takes place in the Δ9 position of pre-existing
(C14 to C24) acyl chains. It is proposed that acyl components from 18∶1 are subjected to chain elongation to form a mixture of 24∶1 isomers
as the final product. Apart from the 24∶1 acyl moiety of the wax esters, in which the double bond was almost exclusively in
the Δ15 position, de novo biosynthetic reactions on acids and alcohols appear to yield related acyl- and alkyl-moieties of
resynthesized wax esters. 相似文献
16.
The lipid fatty acid pattern of normal liver, host liver, and Novikoff hepatoma was determined by gas liquid chromatography,
and Δ6-desaturase activity for linoleic acid was measured in the microsomal fractions. The results showed that, in Novikoff
hepatoma, there is a correlation between the low content of arachidonic acid and the low activity of Δ6-desaturase, a key
enzyme in the biosynthetic pathway of this acid. 相似文献
17.
Harold W. Cook 《Lipids》1981,16(12):920-926
trans-Monounsaturated acids account for up to 3% of the total octadecenoic acyl chains of human brain lipids. To investigate the
influence oftrans-acids on desaturation and chain elongation of fatty acids, in vitro and in vivo experiments with rat brain were performed.
In the in vitro assays of Δ9 desaturation, Δ6 desaturation and chain elongation,trans,trans-dienoic acid was inhibitory, particularly to chain elongation. Slight differences between the inhibitory effects oftrans-monoenoic acids and theircis-isomers were observed. In an in vivo model, unlabeled fatty acid (stearate, oleate, elaidate, linoleate, linoelaidate, arachidonate,
ortrans-monoene from margarine) was injected simultaneously with [1-14C] linoleic acid into the brains of suckling rats. Linoelaidate and oleate inhibited desaturation and elongation of linoleate,
whereas elaidate, stearate andtrans-monoene from margarine were stimulatory. While the demonstration of differences betweencis andtrans monoenic isomers required relatively high levels of the test acids, it appears thattrans-acids can influence desaturation and elongation enzymes that lead to acyl chain modification in the central nervous system.
Portions of this study were presented at the meeting of the American Oil Chemists' Society and the International Society for
Fat Research in New York, NY, April 1980. 相似文献
18.
The biosynthesis of fatty acids in the diatomPhaeodactylum tricornutum was studied. The diatom was incubated with sodium [114C] acetate and the acids [1-14C] palmitic, [1-14C] stearic, [1-14C] linoleic and [1-14C] α-linolenic. The distribution of radioactivity in the products was determined by gas liquid radiochromatography. The diatom
synthesized “de novo” not only saturated and monounsaturated fatty acids, but also linoleic, α-linolenic and other fatty acids
including the highly polyunsaturated 20∶5ω3 and 22∶6ω3. When labeled acetate, stearic, α-linolenic or even linoleic acid were
incubated with the diatom, the polyunsaturated C20 fatty acids synthesized belonged predominantly to the ω 3 family. The existence of Δ9, Δ6, Δ5, Δ4, ω6 and possibly ω3 desaturases
inP. tricornutum is suggested.
Member of the Carrera del Investigador Científico of the Comisión de Investigaciones Científicas de la Provincia de Buenos
Aires.
Member of the Carrera del Investigador Cientifico of the Consejo Nacional de Investigaciones Cientificas y Técnicas. 相似文献
19.
Three groups of rats were fed diets with either 10 weight percent (wt%) of evening primrose oil, safflower oil or soybean
oil for 11 weeks. Diets contained 7.1 wt% linoleic acid +0.8 wt% γ-linolenic acid, 7.6 wt% linoleic acid, or 5.3 wt% linoleic
acid +0.7 wt% α-linolenic acid, respectively. In liver mitochondria as well as in heart, dietary γ-linolenic acid did not
affect the fatty acid profiles of phosphatidylcholnes (PC), phosphatidylethanolamines (PE) or cardiolipins (CL), whereas dietary
α-linolenic acid caused an increased formation of (n−3) polyunsaturated fatty acids (PUFA). The liver Δ6− and Δ5-desaturase
activities determined in vitro were not affected by the dietary fats. In brain PE, which are rich in C22− and C20-(n−3) PUFA,
as well as in testes PC and PE, which are rich in (n−6) PUFA, no effects were found from a partial replacement of dietary
linoleic acid with γ-linolenic acid or α-linolenic acid. In kidney PC, PE, phosphatidylinositol (PI) and CL, 20∶3(n−6) was
moderately elevated to ca. 1% following intake of γ-linolenic acid, whereas partial replacement of linoleic acid with α-linolenic
acid was followed by increased deposition of 22∶6(n−3) in PC and PE of testes and kidney. Thus, no general effect of evening
primrose oil on the content of (n−6) PUFA in rat tissue phospholipids was observed, wheras a significant incorporation of
γ-linolenic acid into liver and adipose tissue triglycerides was found. 相似文献
20.
C. Bertoli L. B. Fay M. Stancanelli D. Gumy P. Lambelet 《Journal of the American Oil Chemists' Society》1998,75(8):1037-1040
The fatty acid composition, tocopherol and tocotrienol content, and oxidative stability of petroleum benzene-extracted Gevuina avellana Mol (Proteaceae) seed oil were determined. Positional isomers of monounsaturated fatty acids were elucidated by gas chromatography-electron
impact mass spectrometry after 2-alkenyl-4,4-dimethyloxazoline derivatization. This stable oil (Rancimat induction period
at 110°C: 20 h) is composed of more than 85% monounsaturated fatty acids and about equal amounts (6%) of saturated and polyunsaturated
(principally linoleic) fatty acids. Unusual positional isomers of monounsaturated fatty acids, i.e., C16:1 Δ11, C18:1 Δ12, C20:1 Δ11, C20:1 Δ15, C22:1 Δ17, and presumably C22:1 Δ19 were identified. The C18:1 Δ12 and C22:1 Δ19 fatty acids are described for the first time in G. avellana seed oil. While only minute quantities of α-, γ-tocopherols and β-, γ- and δ-tocotrienols were found, the oil contained a
substantial amount of α-tocotrienol (130 mg/kg). The potential nutritional value of G. avellana seed oil is discussed on the basis of its composition. 相似文献