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PubMed1989

Measurement of the unbound fraction of long chain nonesterified fatty acids (NEFA) in serum: methodological considerations.

Long-chain nonesterified fatty acids (NEFA) are extensively bound to albumin; knowledge of their unbound concentrations is important in evaluating the numerous biologic effects attributed to these compounds. We measured the unbound fraction of five long-chain NEFA in serum using the equilibrium partition of 14C-NEFA between heptane and aqueous phases. Commercial 14C-NEFA preparations gave non-linear estimates of unbound fraction with serum dilution, consistent with the presence of polar tracer impurities, but 14C-NEFA purified by alkaline ethanol extraction gave an approximately linear relationship between unbound fraction and serum dilution over a 4096-fold range of dilution, provided that pH of the aqueous phase remained stable. Mean unbound percentages were: myristic acid 0.0066, linolenic acid 0.0019, arachidonic acid 0.0017, oleic acid 0.00078 and palmitic acid 0.00061. These data suggest that some previous studies appear to have overestimated the free fraction of long-chain NEFA at physiological albumin concentrations by at least one order of magnitude.

Arachidonic Acids↗
PubMed1978

The role of free fatty acids in the regulation of lipolysis by human adipose tissue cells.

The effect of added fatty acid on lipolysis and cyclic AMP concentration of human adipose tissue cells was studied. The addition of sodium oleate decreased the lipolytic response of adipocytes to 10(-7) M isoproterenol. Inhibition was detectable with the lowest quantity of oleate added, 0.2 mM, and was progressively greater with increasing quantities of added fatty acid. Palmitic and linoleic acids were as effective as oleic acid in suppressing isoproterenol-stimulated lipolysis. Suppression of cyclic AMP formation was detectable within one minute after the addition of oleate. Cyclic AMP formation, suppressed by accumulated fatty acids, could not be stimulated by the addition of fresh isoproterenol. However, after the accumulated fatty acids were removed by buffer change, cyclic AMP formation was stimulated by fresh isoproterenol. These findings are consistent with the view that fatty acids are physiologically significant regulators of lipolysis.

Adipose Tissue↗
PubMed2005

Determination of carotenoids in spear shrimp shells (Parapenaeopsis hardwickii) by liquid chromatography.

The objectives of this study were to develop a high-performance liquid chromatography method for analysis of carotenoids in spear shrimp shells (Parapenaeopsis hardwickii) and to compare the extraction efficiency of carotenoids by supercritical carbon dioxide (SCD) and solvents. Results showed that the most appropriate HPLC method was accomplished by employing a Cosmosil 5C18-AR-II column and a mobile phase of methanol-dichloromethane-acetonitrile (90:5:5, v/v/v) (A) and water (100%) (B) with the following gradient elution: 92% A and 8% B in the beginning, decreased to 4% B in 9.5 min, 1% B in 26 min, 0% B in 35 min, maintained for 25 min, and returned to 92% A and 8% B in 61 min. All-trans-astaxanthin and its two cis isomers, as well as five astaxanthin monoesters and 11 diesters were resolved within 60 min with a flow rate at 2 mL/min and detection at 480 nm. Astaxanthin diesters were found to contain 12 fatty acids, of which palmitic acid and stearic acid constituted a large portion, whereas astaxanthin monoesters were found to contain 10 fatty acids with arachidonic acid dominating. Solvent extraction could generate a higher content of trans-astaxanthin and astaxanthin esters, while SCD extraction could produce greater levels of 9-cis-astaxanthin and 13-cis-astaxanthin.

Carotenoids↗
PubMed1976

Triacylglycerol biosynthesis in rat adipose-tissue homogenates.

The optimum cofactor requirements for triacylglycerol biosynthesis in rat adipose-tissue homogenates containing mitochondrial, microsomal and cytosolic fractions were investigated. In general the optimum concentrations of cofactors for triacylglycerol biosynthesis were found to differ from those for total fatty acid esterification. The results provided further evidence for the key role of phosphatidate phosphohydrolase in the regulation of triacylglycerol biosynthesis. Albumin was included in the incubation medium to permit the use of concentrations of added fatty acids that would swamp the effects of endogenous fatty acids. The addition of albumin had little effect on the incorporation of palmitic acid and stearic acid into lipids including triacylglycerols. By contrast, a critical concentration of albumin (about 60 muM) was required before incorporation of oleic acid or linoleic acid into triacylglycerols occurred. The system was used to study the incorporation of different 1-14C-labelled fatty acids from a mixture of unesterified fatty acids [palmitic acid 30%; stearic acid 10%; oleic acid 40%; linoleic acid 20% (molar percentages)] separately into the positions 1,2 and 3 of triacyl-sn-glycerols. In general the stereo-specific distribution of the labelled fatty acids incorporated into triacylglycerols paralleled the normal distribution of fatty acids within rat adipose-tissue triacylglycerols, suggesting that the specificities of the relevant acyltrasferases have the major role in determining the positional distribution of fatty acids within triacylglycerols.

Adipose Tissue↗
PubMed1987

Increased arachidonic acid levels in phospholipids of human colonic mucosa in inflammatory bowel disease.

1. Colonic mucosa from 19 patients with ulcerative colitis, eight with Crohn's disease and 14 controls were analysed for arachidonic acid (C20:4), linoleic acid (C18:2), oleic acid (C18:1), stearic acid (C18:0) and palmitic acid (C16:0). 2. Gas-liquid chromatography of lipid extracts showed that arachidonic acid was significantly higher in ulcerative colitis (19 +/- 4) and Crohn's disease (20 +/- 3) than in controls (13 +/- 5 micrograms/mg of protein) (means +/- SD). Neither the degree of inflammation nor treatment with sulphasalazine or prednisolone appeared to influence the fatty acid concentrations. 3. Seventy-five to ninety-five per cent of the arachidonic acid was found in the phospholipid fraction after separation by thin-layer chromatography. There were no significant changes in the concentrations of the other fatty acids measured, although oleic acid was lower in inflammatory bowel disease. The ratios of oleic acid to stearic acid and to palmitic acid were lower in inflammatory bowel disease. 4. The alteration in the fatty acid profile may partly explain the increased synthesis of eicosanoids in colonic mucosa in inflammatory bowel disease.

Adolescent↗
PubMed1996

Identification of two molecular species of rat brain phosphatidylcholine that rapidly incorporate and turn over arachidonic acid in vivo.

In vivo rates of arachidonic acid incorporation and turnover were determined for molecular species of rat brain phosphatidylcholine (PtdCho) and phosphatidylinositol (PtdIns). [3H]Arachidonic acid was infused intravenously in pentobarbital-anesthetized rats at a programmed rate to maintain constant plasma specific activity for 2-10 min. At the end of infusion, animals were killed by microwave irradiation, and brain phospholipids were isolated, converted to diacylglycerobenzoates, and resolved as molecular species by reversed-phase HPLC. Most [3H] arachidonate (> 87%) was incorporated into PtdCho and PtdIns, with arachidonic acid at the sn-2 position and with oleic acid (18:1), palmitic acid (16:0), or stearic acid (18:0) at the sn-1 position. However, 10-15% of labeled brain PtdCho eluted in a small peak containing two molecular species with arachidonic acid at the sn-2 position and palmitoleic acid (16:1) or linoleic acid (18:2) at the sn-1 position. Analysis demonstrated that tracer was present in both the 16:1-20:4 and 18:2-20:4 PtdCho species at specific activities 10-40 times that of the other phospholipids. Based on the measured mass of arachidonate in each phospholipid molecular species, half-lives were calculated for arachidonate of < 10 min in 16:1-20:4 and 18:2-20:4 PtdCho and 1-3 h in 16:0-20:4, 18:1-20:4 PtdCho and PtdIns. The very short half-lives for arachidonate in the 16:1-20:4 and 18:2-20:4 PtdCho molecular species suggest important roles for these molecules in brain phospholipid metabolism and signal transduction.

Animals↗
PubMed1998

Peroxisomal Delta3-cis-Delta2-trans-enoyl-CoA isomerase encoded by ECI1 is required for growth of the yeast Saccharomyces cerevisiae on unsaturated fatty acids.

We have identified the Saccharomyces cerevisiae gene ECI1 encoding Delta3-cis-Delta2-trans-enoyl-CoA isomerase that acts as an auxiliary enzyme in the beta-oxidation of (poly)unsaturated fatty acids. A mutant devoid of Eci1p was unable to grow on media containing unsaturated fatty acids such as oleic acid but was proficient for growth when a saturated fatty acid such as palmitic acid was the sole carbon source. Levels of ECI1 transcript were elevated in cells grown on oleic acid medium due to the presence in the ECI1 promoter of an oleate response element that bound the transcription factors Pip2p and Oaf1p. Eci1p was heterologously expressed in Escherichia coli and purified to homogeneity. It was found to be a hexameric protein with a subunit of molecular mass 32, 000 Da that converted 3-hexenoyl-CoA to trans-2-hexenoyl-CoA. Eci1p is the only known member of the hydratase/isomerase protein family with isomerase and/or 2-enoyl-CoA hydratase 1 activities that does not contain a conserved glutamate at its active site. Using a green fluorescent protein fusion, Eci1p was shown to be located in peroxisomes of wild-type yeast cells. Rat peroxisomal multifunctional enzyme type I containing Delta3-cis-Delta2-trans-enoyl-CoA isomerase activity was expressed in ECI1-deleted yeast cells, and this restored growth on oleic acid.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed2000

Effects of fatty acids on uncoupling protein-2 expression in the rat heart.

Fatty acids are thought to play a role in the activity of uncoupling proteins (UCP) and have been shown to regulate the expression of genes encoding proteins involved in fatty acid handling. Therefore, we investigated whether fatty acids, which are the main substrates for the heart, affect rat cardiac UCP-2 expression in vivo and in vitro. After birth, when the contribution of fatty acid oxidation to cardiac energy conversion increases, UCP-2 expression enhanced rapidly. In the adult heart, however, UCP-2 mRNA levels did not alter during conditions associated with either enhanced (fasting, diabetes) or decreased (hypertrophy) fatty acid utilization. Exposure of neonatal cardiomyocytes and embryonic rat heart-derived H9c2 cells to fatty acids (palmitic and oleic acid) for 48 h strongly induced UCP-2 expression. Stimulation of neonatal cardiomyocytes with triiodothyronine also increased UCP-2 mRNA levels, though only in the presence of fatty acids. Ligands specific to the fatty acid-activated transcription factor PPARalpha, but not to PPARgamma, acted as inducers of cardiomyocyte UCP-2 expression. It is concluded that fatty acids promote UCP-2 expression in neonatal cardiomyocytes, which might explain the rapid increase in UCP-2 mRNA in the postnatal heart. However, UCP-2 mRNA levels in the adult heart appear to be insensitive to changes in cardiac fatty acid handling under various pathological conditions.

Aging↗
PubMed1987

The effect of chronic ethanol consumption on the lipids in liver mitochondria.

The ethanol-related alterations in hepatic mitochondrial phospholipids are primarily changes in acyl chain composition. There are no alterations in the unesterified cholesterol content in the mitochondrion, as measured by the cholesterol-phospholipid ratio. Moreover, the distribution of mitochondrial phospholipids are not changed as a result of chronic ethanol consumption. There was a significant ethanol-related decrease (18%) in the phospholipid-protein ratio in mitochondria from rats maintained on a low-fat diet, which was not observed in studies where animals were fed diets containing a higher proportion of lipid. This effect of dietary composition on the phospholipid-protein ratio was also paralleled by the interaction between diet and ethanol in influencing the phospholipid acyl composition. The alterations in acyl chain distribution indicated that ethanol consumption stimulated elongation of palmitic acid, and depressed the delta 5 desaturation step required for the formation of arachidonic acid. Elongation of palmitic acid was stimulated in studies where animals were fed diets with moderate amounts of fat, whereas depressed synthesis of arachidonate occurred more frequently, but not exclusively, in studies where low-fat diets were employed. These results indicate that there is a significant interaction between diet and ethanol in eliciting changes in hepatic mitochondrial phospholipids. The significant decrease in the linoleic acid content of cardiolipin and the more prominent ethanol-associated alterations in mitochondrial phospholipids suggest that ethanol consumption depresses the phospholipid reacylation activities associated with the mitochondrion. The above observations indicate, therefore, that the alterations occurring in mitochondrial phospholipids are influenced by ethanol-related changes in mitochondrial enzymes involved in phospholipid metabolism. In addition, alterations in the availability of fatty acids due to ethanol-related changes in microsomal elongation and desaturation activities also appear to affect the fatty acid composition of phospholipids in mitochondria from ethanol-fed animals.

Alcoholism↗
PubMed1974

Remodeling of granulocyte membrane fatty acids during phagocytosis.

During phagocytosis, new phospholipid is synthesized from triglyceride fatty acid and may be utilized to form the membranes of phagocytic vesicles. In addition, hydrogen peroxide, which can peroxidize unsaturated fatty acids, is generated. Since both of these processes could change membrane fatty acid composition during the conversion of cytoplasmic granules and plasma membranes to phagosomes, the lipid compositions of these structures were examined. Phagocytic vesicles were prepared by density gradient centrifugation of polystyrene latex particles after phagocytosis. Granule and plasma membrane fractions were isolated by density gradient and differential centrifugation. Phospholipids and fatty acids were analyzed by thin-layer chromatography and gas-liquid chromatography. While whole cells, granules, plasma membranes, and phagosomes were all similar in phospholipid composition, phagosome fatty acids were significantly more saturated than those of the other fractions. This was primarily due to reduced oleic and arachidonic acids and increased palmitic acid in the phagocytic vesicle lipids. Plasma membrane was also more saturated in comparison to whole cells and granules. However, this difference was not sufficient to explain the marked comparative saturation of the phagosomes. The observed increase in fatty acid saturation in these lipids may have been induced by a combination of either peroxidative destruction of polyunsaturated fatty acids or phospholipase activity, coupled with reacylation mechanisms favoring saturated fatty acids.

Arachidonic Acids↗
PubMedDate not supplied

Composition and antimicrobial activity of essential oil and hexane-ether extract of Tanacetum santolinoides (dc.) Feinbr. and Fertig.

Tanacetum santolinoides, Essential Oil Composition, n-Hexane-Ether Extract Composition The essential oil of the aerial parts of Tanacetum santolinoides was analyzed by capillary GLC and GLC-MS. Altogether 30 components were identified. The main constituents were thymol (18%), trans-thujone (17.5%), trans-chrysanthenyl acetate (13.2%), cis-chrysanthenyl acetate (9.2%), umbellulone (9.7%) and 1,8-cineole (4.7%). Similar essential oil pattern in addition to palmitic acid methyl ester, palmitic acid, stigmasterol, sitosterol and two flavonoidal aglycons were found in the n-hexane-ether extract. The oil showed strong in vitro activity against E. coli, Bacillus subtilis and Candida albicans.

Anti-Bacterial Agents↗
PubMed1979

Changes in the fatty acid composition of Drosophila melanogaster during development and ageing.

In Drosophila melanogaster the saturated fatty acids increase in amount early in pupal development relative to the concentrations in late third instar larvae, then decline to the levels characteristic of one-day-old adults. Conversely, the monounsaturated fatty acids decline in content early in pupal development, then increase late in the pupal period. Lauric acid (12:0), myristic acid (14:0) and palmitoleic acid (16:1) become more prominent and oleic acid (18:1) and palmitic acid (16:0) less prominent as the adult ages. At about 40 days of adult age myristic acid (14:0) begins to decrease and oleic acid (18:1) to increase. Within 20 days of eclosion males and females contain different amounts of myristic acid (14:0), palmitic acid (16:0) and oleic acid (18:1).

Aging↗
PubMed2005

[Study on the encapsulation technique of high purity gamma-linolenic acid, part 1--saponification reaction and saponification value].

OBJECTIVE: To measure the saponification value and fatty acid formation of evening primrose oil, to study the effects of pH value on production yield and fatty acid formation during the saponification reaction, and to provide rationales for the selection of raw material, the enhancement of production yield of saponification, and the encapsulation of gamma-linolenic acid with urea. METHOD: To measure fatty acid's formation with gas chromatographic method and to measure the saponification value. RESULT: The content of gamma-linolenic acid is 7%-10% in evening primrose oil. The content of gamma-linolenic acid is inversely correlated with that of unsaturated fatty acid. The saponification value, the amount of KOH for saponification of evening primrose oil, and the pH value for subsequent isolations of oils are determined. From the measurement of fatty acids of evening primrose oil in two different cultivation locations, the content of gamma-linolenic acid is determined to be 7%-10%, unsaturated oils account for 90%. CONCLUSION: The saponification value of evening primrose oil is between 180-200, pH value of isolated oil is 1.5-2.0 after saponification reaction. Fatty acids mainly include palmitic acid, stearic acid, oleic acid, linolic acid and gamma-linolenic acid.

Fatty Acids, Essential↗
PubMed2003

Effects of long chain fatty acids on lipid and glucose metabolism in monolayer cultures of bovine hepatocytes.

The objectives were to determine the long-term (48 h) effects of specific long chain fatty acids on hepatic lipid and glucose metabolism in monolayer cultures of bovine hepatocytes. From 16 to 64 h after plating, hepatocytes from three 7- to 10-d-old calves were exposed to one of the following treatments: 1 mM palmitic acid (1 mM C16:0), 2 mM palmitic acid (2 mM C16:0), or 1 mM palmitic acid plus 1 mM of either stearic (C18:0), oleic (C18:1), linoleic (C18:2), linolenic (C18:3), eicosapentaenoic (C20:5), or docosahexaenoic (C22:6) acid, or 0.5 mM each of eicosapentaenoic and docosahexaenoic acid (C20:5 + C22:6). The two treatments containing 2 mM of saturated fatty acids, 2 mM C16:0 and 1 mM C16:0 plus 1 mM C18:0, increased beta-hydroxybutyrate concentrations in the medium and [1-(14)C]palmitic acid oxidation to acid-soluble products compared with all other treatments. The treatment containing C22:6 increased total cellular triglyceride content and incorporation of [1-(14)C]palmitic acid into cellular triglycerides. The treatments containing C22:6 or C20:5 + C22:6 increased [1-(14)C]palmitic acid metabolism to phospholipids and cholesterol. The presence of C22:6 in the medium decreased metabolism of [2-(14)C]propionic acid either to glucose in the medium or to cellular glycogen. Overall, fatty acids differed in their effects on lipid and glucose metabolism in monolayer cultures of bovine hepatocytes with C22:6 eliciting the most profound changes.

3-Hydroxybutyric Acid↗
PubMed1991

Long-chain-acyl-CoA synthetase and very-long-chain-acyl-CoA synthetase activities in peroxisomes and microsomes from rat liver. An enzymological study.

We have investigated the palmitic acid (C16:0) and cerotic acid (C26:0) activating activities in rat-liver microsomes and peroxisomes. The activation of the two fatty acids showed similar dependencies on ATP and coenzyme A, reflected in about equal apparent Km values both in microsomes and peroxisomes. In microsomes and peroxisomes similar apparent Km values for palmitic acid were found (15 microM and 22.8 microM, respectively), whereas apparent Km values for cerotic acid were 8.4 microM and 1.0 microM in microsomes and peroxisomes, respectively. The activation of cerotic acid was found to be inhibited to a progressively greater extent by increasing concentrations of 1-pyrenedecanoic acid (P10) as compared to the activation of palmitic acid, both in microsomes and peroxisomes. The inhibition by P10 of palmitic acid activation and cerotic acid activation was non-competitive in both organelles. From the observation that P10 activation is not affected by palmitic acid and cerotic acid, we conclude that P10 is activated by a distinct enzyme. Furthermore, our results are in accordance with earlier suggestions that activation of cerotic acid is brought about by an enzyme distinct from the palmitoyl-CoA synthetase.

Animals↗
PubMed1993

Decreased mitochondrial oxidation of fatty acids in pregnant mice: possible relevance to development of acute fatty liver of pregnancy.

Severe impairment of the beta-oxidation of fatty acids, as a consequence of a single factor or a combination of different causes, leads to microvesicular steatosis of the liver. In an effort to understand the mechanism(s) leading to the development of acute fatty liver of pregnancy in some women, we determined the effects of pregnancy on the mitochondrial oxidation of fatty acids in mice. In vivo, the rate of oxidation of the whole fatty-acid chain length was determined by measuring the rate of exhalation of [14C]CO2 after intragastric administration of a tracer dose of [U-14C]palmitic acid. [14C]CO2 exhalation was not significantly decreased at 14 days of gestation, but it had declined by 40% at 18 days of gestation (i.e., 24 to 48 hr before delivery). The rate of first beta-oxidation cycle was assessed by measuring the rate of [14C]CO2 exhalation after administration of [1-14C]octanoic acid, [1-14C]butyric acid or [1-14C]palmitic acid. [14C]CO2 exhalation had declined by 60%, 46%, and 24% after administration of [1-14C]octanoic acid, [1-14C]butyric acid and [1-14C]palmitic acid, respectively, in 18-day-pregnant mice. Total hepatic lipids and triglycerides, expressed per gram of liver, remained unchanged in 18-day-pregnant mice. In vitro, the rate of mitochondrial beta-oxidation (expressed per milligram of protein) had decreased by 47% at 18 days' gestation with [U-14C]palmitic acid as substrate and by 33% with [1-14C]octanoic acid but remained unchanged with [1-14C]palmitic acid. The activity of the tricarboxylic acid cycle, assessed by the formation of [14C]CO2 from [1-14C]acetic acid, had decreased by 24%. We conclude that the mitochondrial oxidation of fatty acids decreased during late-term pregnancy in mice as a consequence of both decreased mitochondrial beta-oxidation of medium-chain fatty acids, and decreased activity of the tricarboxylic acid cycle. We suggest that this effect, in combination with other factors, may contribute to the development of fatty liver of pregnancy in some pregnant women.

Acyl-CoA Dehydrogenase↗
PubMed2004

Influence of harvest date and crop yield on the fatty acid composition of virgin olive oils from cv. Picual.

In this study was analyzed the effect of crop year and harvesting time on the fatty acid composition of cv. Picual virgin olive oil. The study was carried out during the fruit ripening period for three crop seasons. The mean fatty acid composition of Picual oils was determined. The oils contained palmitic acid (11.9%), oleic acid (79.3%), and linoleic acid (2.95%). The content of palmitic acid and saturated fatty acids decreased during fruit ripening while oleic and linoleic acids increased. The amount of stearic and linolenic acids decreased. The amount of saturated acids, palmitic and stearic, and the polyunsaturated acids linoleic and linolenic was dependent on the time of harvest, whereas the amount of oleic acid varied with the crop year. The differences observed between crop years for both palmitic and linoleic acid may be explained by the differences in the temperature during oil biosynthesis and by the amount of summer rainfall for oleic acid content. A significant relationship was observed between the MUFA/PUFA ratio and the oxidative stability measured by the Rancimat method.

Climate↗
PubMed1980

Substrate control of termination of fatty acid biosynthesis by fatty acid synthetase from Brevibacterium ammoniagenes.

The pattern of fatty acids produced by the fatty acid synthetase complex of Brevibacterium ammoniagenes under several conditions was examined. The fatty acid synthetase obtained from B. ammoniagenes produced oleic acid as well as saturated fatty acids (palmitic and stearic acids). The relative proportions of palmitic to stearic acids varied over a wide range. Such alterations were dependent on the malonyl-CoA concentration and the ratio of acetyl-CoA to malonyl-CoA concentrations. At malonyl-CoA concentrations higher than 100 microM, stearic acid accounted for more than 90% of the saturated fatty acids and the pattern of fatty acid synthesized was independent on the ratio of acetyl-CoA to malonyl-CoA. At malonyl-CoA concentrations lower than 100 microM, raising the acetyl-CoA/malonyl-CoA ratio increased the percentage of palmitic acid. However, the proportion of oleic acid produced remained almost constant under all conditions tested.

Acetyl Coenzyme A↗