The incorporation of cyclopropane fatty acids by essential fatty acid-deficient rats.
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Adipose Tissue↗
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Fatty acid chain length combinations in ascitic fluid triglycerides containing lymphatic absorbed medium-chain fatty acids.
Information on the fatty acid chain length combinations in lymph triglycerides containing medium-chain fatty acids was obtained by combining the fatty acid composition and the carbon number composition of triglycerides from ascitic fluid of patients on medium-chain triglyceride-containing diets. In these triglycerides, the major part of the medium-chain fatty acids was present in combination with long-chain fatty acids. These results indicate that part of the lymphatic absorbed medium-chain fatty acids are absorbed as triglycerides which also contain long-chain fatty acids.
Ascites↗
Inhibition of fatty acid delta 6- and delta 5-desaturation by cyclopropene fatty acids in rat liver microsomes.
delta 6-Desaturation of linoleic acid and delta 5-desaturation of dihomo-gamma-linolenic acid were measured in liver microsomes from rats fed fresh Baobab seed oil containing cyclopropene fatty acids (malvalic acid and sterculic acid) or heated Baobab seed oil practically devoid of these fatty acids or control oil. The presence of cyclopropene fatty acids in the fresh Baobab oil diet highly depressed both desaturations, but delta 6- more than delta 5-desaturation. The decreased capacity of microsomes to desaturate was reflected in the lower arachidonic acid content in microsomal phospholipids from rats fed this oil. However it was also lower in rats fed heated oil although in vitro delta 6- and delta 5-desaturation were not depressed. When liver microsomes prepared from rats fed the control diet were used for the desaturation assays, the presence of free malvalic or sterculic acid in the medium, also highly depressed delta 6- and delta 5-desaturation. The incorporation of arachidonic acid, the product of delta 5-desaturation, into phospholipids was also highly depressed, while that of the precursor dihomo-gamma-linolenic acid was not. This suggests that cyclopropene fatty acids specifically inhibit incorporation of the delta 5-desaturation product into phospholipids or that they specifically inhibit desaturation of the substrate previously incorporated into a membrane phospholipid.
Animals↗
Adenylate cyclase activity, membrane fluidity and fatty acid composition of rat heart in essential fatty acid deficiency.
Three groups of male, weanling, Sprague-Dawley rats were fed diets containing 7% hydrogenated coconut oil, 6.6% hydrogenated coconut oil + 0.4% corn oil, or 7% corn oil for 8-17 weeks. These diets provided 0% (EFAD group), 0.5% (MEFAD group) or 5% (CONTROL group) of the total energy as linoleic acid, respectively. Crude plasma membranes were prepared from heart and assayed for adenylate cyclase activity. Both basal and fluoride-stimulated activity was lower in the membranes from EFAD and MEFAD rats than that of the controls. The double bond index of total lipids and phospholipids, and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were not appreciably different in the membranes from the three dietary groups. The fatty acid composition of total phospholipids of the membranes, however, was quite different and indicative of biochemical changes typical of an EFA deficiency. Feeding of the control diet to the EFAD or MEFAD rats for up to 6 weeks did not alleviate completely the changes in adenylate cyclase activity although the fatty acid patterns were restored to the normal levels. There was also a decrease in the number of [3H]-DHA binding sites in heart of EFAD rats as compared with their controls. The results suggest that the changes induced by EFA deficiency in the acyl group composition of membrane phospholipids and in the number of beta-adrenergic receptors may be important in regulating adenylate cyclase activity in the heart.
Adenylyl Cyclases↗
Studies on the mechanism of fatty acid synthesis. VII. Biosynthesis of fatty acids from malonyl CoA.
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Adipogenesis↗
Identification by GC-FID and GC-MS of amino acids, fatty and bile acids in binding media used in works of art.
GC-FID was used as single methodology for the identification and differentiation of proteins, lipids and ox bile from binders used in artistic paintings. The samples were hydrolyzed by HCl. Subsequently, the simultaneous formation of volatile derivatives of the amino, fatty and bile acids with ethyl chloroformate was performed quickly and safely in an aqueous medium. The derivatives were separated by capillary GC and characterized by GC-MS. The ageing of drying oils was studied, identifying pelargonic acid among other degradation products. Proteinaceous and lipoid binding media were characterized by means of the quotients between the areas of the peaks for each amino or fatty acid with respect to the area of the peak for alanine or palmitic acid. Fatty acids from ox bile were easily identified by their retention times characteristic for eicosanoic, docosanoic and pentadecanoic acids. The suggested method was applied to the analysis of binders in baroque paintings by Palomino in Valencia (Spain). Animal gelatine and linseed oil were found.
Amino Acids↗
Net release of individual fatty acids from white adipose tissue during lipolysis in vitro: evidence for selective fatty acid re-uptake.
During lipolysis, adipose tissue triacylglycerols (TAG) undergo concurrent breakdown and synthesis because some of the newly hydrolysed and released non-esterified ('free') fatty acids (NEFA) can subsequently be taken up and re-esterified. The present study examines whether and how the release of individual fatty acids is affected by the re-uptake of some of the newly hydrolysed fatty acids in vitro during lipolysis. To alter fatty acid release and re-uptake, adipose tissue fragments and isolated adipocytes from rats were incubated under various conditions, i.e. several cell concentrations or adipose fragment quantities, with or without glucose. In the various conditions tested, the NEFA/glycerol molar ratio ranged from 1.5 to 2.9. Whatever the incubation conditions, including those resulting in very low, medium or high fatty acid re-uptake (as assessed by the NEFA/glycerol ratio), the percentage weight of fatty acids in NEFA was significantly different from that in TAG for 20-24 of the 35 fatty acids that were considered. Thus the greater the fatty acid re-uptake, the higher the proportion of polyunsaturated fatty acids and the lower the proportion of long-chain saturated and monounsaturated fatty acids in NEFA. Moreover, the relative mobilization (%NEFA/%TAG) of the least readily mobilized fatty acid (C(22:1,n-11)) was 6.2-fold lower than that of the most readily mobilized fatty acid (C(20:5,n-3)) under conditions of very low fatty acid re-uptake, and 14.8-fold lower under conditions of high fatty acid re-uptake, indicating a widening of the range of relative mobilizations. We conclude that the composition of the NEFA pool is affected by the rate of fatty acid re-uptake. This provides strong evidence for the selective re-uptake of adipose tissue fatty acids during lipolysis.
Adipose Tissue↗
Evidence for fatty acid oxidation in human placenta, and the relationship of fatty acid oxidation enzyme activities with gestational age.
Fetal disorders of mitochondrial fatty acid oxidation have recently been associated with obstetric complications including pre-eclampsia, Hemolysis, Elevated Liver enzymes, Low Platelets (HELLP) syndrome, placental floor infarct, and Acute Fatty Liver of Pregnancy (AFLP). These diseases occur in about a third of the mothers who are heterozygous for a defect in long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) enzyme and who bear a fetus homozygous for the defect. The mechanism of this association is not clearly understood. In this study, we provide evidence that the placenta may be the site of production of toxic intermediates of fatty acid metabolism, which accumulate to cause liver damage in the mother. We show that two critical enzymes of long chain fatty acid metabolism, long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and short chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD), are active in the normal human placenta. There is an inverse correlation between the enzyme activity of both the enzymes and maternal gestational age during the second and third trimesters. We believe that the demonstration of fatty acid oxidation enzyme activity by the placenta is the first step towards assessing a possible role for fetal/placental fatty acid oxidation defects in the pathogenesis of a subset of pregnancy complications.
3-Hydroxyacyl CoA Dehydrogenases↗
Metabolism of n-3 and n-6 fatty acids in Atlantic salmon liver: stimulation by essential fatty acid deficiency.
Oxidation, esterification, desaturation, and elongation of [1-14C]18:2n-6 and [1-14C]18:3n-3 were studied using hepatocytes from Atlantic salmon (Salmo salar L.) maintained on diets deficient in n-3 and n-6 polyunsaturated fatty acids (PUFA) or supplemented with n-3 PUFA. For both dietary groups, radioactivity from 18:3n-3 was incorporated into lipid fractions two to three times faster than from 18:2n-6, and essential fatty acids (EFA) deficiency doubled the incorporation. Oxidation to CO2 was very low and was independent of substrate or diet, whereas oxidation to acid-soluble products was stimulated by EFA deficiency. Products from 18:2n-6 were mainly 18:3n-6, 20:3n-6, and 20:4n-6, with minor amounts of 20:2n-6 and 22:5n-6. Products from 18:3n-3 were mainly 18:4n-3, 20:5n-3, and 22:6n-3, with small amounts of 20:3n-3. The percentage of 22:6n-3 in the polar lipid fraction of EFA-deficient hepatocytes was fourfold higher than in n-3 PUFA-supplemented cells. This correlated well with our other results obtained after abdominal injection of [1-14C]18:3n-3 and [1-14C]18:2n-6. In hepatocytes incubated with [4,5-3H]-22:6n-3, 20:5n-3 was the main product. This retroconversion was increased by EFA deficiency, as was peroxisomal betaoxidation activity. This study shows that 18:2n-6 and 18:3n-3 can be elongated and desaturated in Atlantic salmon liver, and that this conversion and the activity of retroconversion of very long chain PUFA is markedly enhanced by EFA deficiency.
Animals↗
[Experimental studies on the mechanism of fatty liver formation induced by ethionamide. 3. Fatty acid composition of ethionamide-induced fatty liver and epididymal adipose tissue, and serum free fatty acid in ethionamide-administered rat].
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Adipose Tissue↗
Structural studies on human muscle fatty acid binding protein at 1.4 A resolution: binding interactions with three C18 fatty acids.
BACKGROUND: Muscle fatty acid binding protein (M-FABP) is one of a family of cytosolic lipid-binding proteins involved in fatty acid processing. In order to investigate the precise interactions between M-FABP and its ligands and to understand the structural basis of differential binding affinity, we have compared the structures of M-FABP in complex with three C18 fatty acids. RESULTS: We describe the crystal structures of M-FABP in complex with n-octadecanoate (stearate), trans-delta 9-octadecenoate (elaidate) and cis-delta 9-octadecenoate (oleate). These structures were refined using least-squares positional and anisotropic temperature factor refinement to final R-factors of 11.4%, 12.1% and 13.2% respectively for all the data between 8.0 A and 1.4 A resolution. CONCLUSIONS: Stearate, elaidate and oleate each adopt highly similar U-shaped conformations when they bind to M-FABP within a large interior binding cavity, which also contains 13 ordered water molecules. The atomic structure of the protein is virtually identical, regardless of the nature of the bound ligand. The fatty acid is thought to enter the interior cavity of the protein via a portal in its surface while interior solvent is released through a secondary opening. The ligand affinity can be correlated with the conformational energy and the solubility of the bound ligand.
Carrier Proteins↗
Free fatty acid metabolism in the forearm at rest: muscle uptake and adipose tissue release of free fatty acids.
Free fatty acid (FFA) metabolism in forearm skeletal muscle at rest was studied during continuous intrabrachial arterial ininfusion of [1-14C] oleic acid in 14 normal subjects in the postabsorptive state. Total oleic acid uptake by muscle accounted for at least 65% and perhaps as much as 86% of the measured O2 consumption. The respiratory quotient (0.74) indicated predominant oxidation of lipid. Glucose was a minor substrate for oxidation. Concentrations of six individual free fatty acids were measured in arterial (A), deep venous (DV), and superficial venous (SV) plasma in 25 subjects. There were positive A-DV differences, reflecting net muscle uptake, for each FFA. The extraction ratio (A-DV)/A was greatest for oleic acid. Output of each free fatty acid from subcutaneous adipose tissue was proportional to its arterial concentration, except for stearic acid. There was no stearic acid output. Correction of (A-DV)/A to account for contribution of perimuscular adipose tissue to FFA in DV led to the conclusion that oleic acid was preferentially extracted from arterial blood by forearm muscle. It accounted for 51% of the total FFA uptake, although it comprised only 43% of total FFA in arterial plasma. Total FFA uptake by muscle was more than sufficient to account for all of the measured O2 consumption, suggesting that some of the extracted FFA may be stored in muscle for oxidation at a latter time.
Adipose Tissue↗
PRODUCTION OF VOLATILE FATTY ACIDS BY SOME LACTIC ACID BACTERIA. II. SELECTIVE FORMATION OF VOLATILE FATTY ACIDS BY DEGRADATION OF AMINO ACIDS.
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Amino Acids↗
Prediction of milk fatty acid profile in dairy cows fed dietary fat differing in fatty acid composition.
The objective of this work was to predict changes in milk fat composition caused by differences in dietary fat. Twenty-two references describing 35 experiments and 108 treatments were used in the analysis. For lauric, myristic, and palmitic acids in milk, proportions in the dietary fat and the total dietary fat concentration were important predictors for their concentrations in milk as well as for stearic and oleic acids in milk. Using a model that included these four parameters, the residual standard deviation around the observed versus predicted line within experiments was approximately 10% of the mean for short-chain fatty acids (< C12); for lauric, myristic, palmitic, and oleic acid; and for total C18 fatty acids in milk. The model also effectively predicted milk fatty acid profile with respect to lauric, myristic, palmitic, and oleic acid and total C18 fatty acids across experiments despite differences in breed, basal diet, and milk yield among experiments. The content of short-chain acids, stearic acid, and poly-unsaturated fatty acids were less effectively predicted across experiments. Possible explanations for the differing predictabilities for different milk fatty acids are discussed.
Animals↗
Postprandial lipoprotein lipase, insulin and gastric inhibitory polypeptide responses to test meals of different fatty acid composition: comparison of saturated, n-6 and n-3 polyunsaturated fatty acids.
OBJECTIVE: The present study was carried out to investigate effects of meals, rich in either saturated fatty acids (SFA), or n-6 or n-3 fatty acids, on postprandial plasma lipid and hormone concentrations as well as post-heparin plasma lipoprotein lipase (LPL) activity. DESIGN: The study was a randomized single-blind study comparing responses to three test meals. SETTING: The volunteers attended the Clinical Investigation Unit of the Royal Surrey County Hospital on three separate occasions in order to consume the meals. SUBJECTS: Twelve male volunteers with an average age of 22.5 +/- 1.4 years (mean +/- SD), were selected from the University of Surrey student population; one subject dropped out of the study because he found the test meal unpalatable. INTERVENTIONS: Three meals were given in the early evening and postprandial responses were followed overnight for 11h. The oils used to prepare each of the three test meals were: a mixed oil rich in saturated fatty acids (SFA) which mimicked the fatty acid composition of the current UK diet, corn oil, rich in n-6 fatty acids and a fish oil concentrate (MaxEPA) rich in n-3 fatty acids. The oil under investigation (40 g) was incorporated into the test meals which were otherwise identical [208 g carbohydrates, 35 g protein, 5.65 MJ (1350 kcal) energy]. Postprandial plasma triacylglycerol (TAG), gastric inhibitory polypeptide (GIP), and insulin responses, as well as post-heparin LPL activity (measured at 12 h postprandially only) were investigated. RESULTS: Fatty acids of the n-3 series significantly reduced plasma TAG responses compared to the mixed oil meal (P < 0.05) and increased post-heparin LPL activity 15 min after the injection of heparin (P < 0.01). A biphasic response was observed in TAG, with peak responses occurring at 1 h and between 3-7 h postprandially. GIP and insulin showed similar responses to the three test meals and no significant differences were observed. CONCLUSION: We conclude that fish oils can decrease postprandial plasma TAG levels partly through an increase in post-heparin LPL activity, which however, is not due to increased GIP or insulin concentrations.
Adult↗
Plasma fatty acid status in Moroccan children: increased lipid peroxidation and impaired polyunsaturated fatty acid metabolism in protein-calorie malnutrition.
In previous studies on plasma fatty acid and antioxidant status in 29 malnourished Moroccan children (12 with mild protein-calorie malnutrition, 17 with severe protein-calorie malnutrition) compared to 15 healthy control children from the same area, we pointed out that these populations were heterogeneous in terms of their essential fatty acid and antioxidant status. The aim of the present study was to classify the children using the Waterlow classification and their essential fatty acid status. The discrepancies in lipid parameters, nutritional and inflammatory markers, blood oxidative indexes, antioxidant micronutrients or trace elements (selenium, zinc, vitamin E) related to polyunsaturated fatty acids were checked in these populations. Eight of the control subjects and nine of the severe protein-calorie malnutrition children were essential fatty acid-deficient, compared to only one of the mild protein-calorie malnutrition group. Examination of the essential fatty acid-sufficient subjects with mild protein-calorie malnutrition, compared to the essential fatty acid-sufficient control subjects, showed only a decrease in Z scores and a non-significant decrease in selenium and vitamin E. In severely malnourished children, albumin, cholesterol and low density lipoprotein (LDL) cholesterol, plasma selenium, vitamin E and zinc were low, whereas inflammatory proteins and triglycerides were high. These features worsened with essential fatty acid deficiency. In all protein-calorie malnutrition subjects, there was oxidative stress (increase in thiobarbituric-acid reactants, imbalance between plasma polyunsaturated fatty acid, vitamin E and selenium levels), even in the absence of essential fatty acid deficiency. Monounsaturated fatty acids, oleic acid/stearic acid (C18:1 n-9/C18:0) delta9 desaturase and n-3 and n-6 elongase activity indexes increased. The C18:1/C18:0 delta9 desaturase activity index was negatively correlated to Z scores (r = -0.44, P< 0.01 for Z score weight, r = -0.39, P < 0.01 for Z score height), albumin (r = -0.82, P < 0.01) and zinc (r = -0.51, P< 0.01) levels. In essential fatty acid-deficient, severe protein-calorie malnutrition subjects, delta6 desaturase activity was impaired, and there was a non-significant decrease in arachidonic acid. Essential fatty acid deficiency is a type of malnutrition, and is associated with an aggravation of all parameters in severe protein-calorie malnutrition. The increase in the C18:1/C18:0 delta9 desaturase activity and enhanced lipid peroxidation without any essential fatty acid deficiency could be early markers of protein-calorie malnutrition.
Antioxidants↗
Ultrasound in fatty acid chemistry: synthesis of a 1-pyrroline fatty acid ester isomer from methyl ricinoleate.
A novel 1-pyrroline fatty acid ester isomer (viz. 8-5-hexyl-1-pyrrolin-2-yl) octanoate) has been synthesized from methyl ricinoleate by two routes with an overall yield of 42 and 30%, respectively. Most of the reactions are carried out under concomitant ultrasonic irradiation (20 KHz, ca. 53 watts/cm2). Under such a reaction condition, the reaction time is considerably shortened, and product yields are high. Dehydrobromination under concomitant ultrasonic irradiation of methyl 9, 10-dibromo-12-hydroxyoctadecanoate with KOH in EtOH furnishes methyl 12-hydroxy-9-octadecynoate (66%) within 15 min. Hydration of the latter under ultrasound with mercury(II)acetate in aqueous tetrahydrofuran yields exclusively methyl 12-hydroxy-9-oxo-octadecanoate (95%) in 30 min. The hydroxy group in the latter compound is transformed to the azido function via the mesylate, and treatment of the azido-oxo intermediate (methyl 12-azido-9-oxooctadecanoate) with Ph3P under ultrasonic irradiation furnishes the requisite 1-pyrroline fatty acid ester (77%). The same azido-oxo intermediate has also been obtained by the oxidation of methyl 12-azido-9-cis-octadecenoate using benzoquinone and a catalytic amount of Pd(II)chloride in aqueous tetrahydrofuran under concomitant ultrasonic irradiation (90 min) to give the product in 45% yield. The latter reaction does not take place even under prolonged silent stirring of the reaction mixture.
Esters↗
The intracellular distribution of fatty acids in rat liver. The fatty acids of intracellular compartments.
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Cytoplasm↗