gamma-linolenic-acid and stearic-acid

Fatty acids have been shown to cause death of rat and human primary pancreatic beta cells and of insulin-producing cell lines. These studies focused mainly on saturated and monounsaturated FA such as palmitic, stearic and oleic acids. In this study, we have performed a comparison of the toxicity of a wider range of FA. The toxicity of different FA to insulin-producing RINm5F cells was assessed by flow cytometry measuring loss of plasma membrane integrity and increase in DNA fragmentation. Additionally, the FA induced neutral lipid accumulation and the FA composition were determined. Palmitic, linoleic, gamma-linolenic, oleic, stearic, and eicosapentaenoic acid caused DNA fragmentation of insulin-producing RINm5F cells. Loss of membrane integrity was mainly caused by linoleic and gamma-linolenic acid. There was no correlation between cytotoxicity and the abundance of the FA in the cells as determined by HPLC analysis. Taken as whole, the toxic effect of the FA on insulin-producing RINm5F cells varied irrespective of the chain length and the degree of unsaturation. In these cells PA and LA exhibited the highest toxicity, whereas AA was not toxic. In addition, the toxicity of most tested FA was inversely related to low NLA, except for AA and EPA. The results of this study contribute to the understanding of the role of FA in the impairment of pancreatic beta cell function that occurs in type 2 diabetes and obesity.

Topics: Animals; Arachidonic Acid; Cell Line, Tumor; Cell Membrane; Chromatography, High Pressure Liquid; DNA Fragmentation; Docosahexaenoic Acids; Dose-Response Relationship, Drug; Eicosapentaenoic Acid; Fatty Acids; Fatty Acids, Unsaturated; Flow Cytometry; gamma-Linolenic Acid; Insulin; Insulinoma; Linoleic Acid; Lipids; Oleic Acid; Palmitic Acid; Rats; Stearic Acids

In the present study, the effects of C18 fatty acids with different numbers of double bonds, SA (stearic acid; C18:0), OA (oleic acid; C18:1), LA (linoleic acid; C18:2) and gamma-LNA (gamma-linolenic acid; C18:3), on ROS (reactive oxygen species) production by Jurkat (a human T-lymphocyte-derived cell line) and Raji (a human B-lymphocyte-derived cell line) cells were investigated. ROS production was determined by NBT (Nitro Blue Tetrazolium) reduction (intracellular and extracellular ROS production) and by dihydroethidium oxidation using flow cytometry (intracellular ROS production). The effectiveness on ROS production was gamma-LNA

Topics: Analysis of Variance; B-Lymphocytes; Cell Line; Fatty Acids; Flow Cytometry; gamma-Linolenic Acid; Humans; Jurkat Cells; Linoleic Acid; Oleic Acid; Reactive Oxygen Species; Stearic Acids; Stimulation, Chemical; T-Lymphocytes

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.. To measure fatty acid's formation with gas chromatographic method and to measure the saponification value.. 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%.. 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.

Topics: Fatty Acids, Essential; gamma-Linolenic Acid; Hydrogen-Ion Concentration; Linoleic Acids; Oenothera biennis; Oleic Acid; Palmitic Acid; Plant Oils; Plants, Medicinal; Seeds; Stearic Acids; Technology, Pharmaceutical; Urea

We studied the effects of five high-fat semi-purified diets varying at a 4% (w/w) level in either stearic, oleic, linoleic, alpha-linolenic, or gamma-linolenic acid on body fat and energy metabolism in BALB/c mice. A diet containing caprylic, capric, lauric, and myristic acid was used as a reference diet and a diet with 4% conjugated linoleic acid (CLA) was used as a positive control as it is known to effectively lower body fat in mice. The diets were fed for 35 d. Body fat was significantly lower in the CLA group than in the other groups but was not significantly different among the non-CLA groups. Among the non-CLA groups, the linoleic acid group tended to have the highest and the alpha-linolenic acid group the lowest proportion of body fat. In energy-balance studies, the percentage of energy intake that was stored in the body was significantly lower in the CLA group compared with the other dietary groups. The percentage of energy intake eliminated in excreta was highest in the stearic acid group followed by the gamma-linolenic acid group. These results were reflected in apparent fat digestibility, which was lowest in the stearic acid group. The percentage of energy intake expended as heat was highest in the CLA-fed mice. The results of the present study suggest that body fat and energy accretion in mice fed diets containing different C18 fatty acids is by far the lowest with CLA and that linoleic acid produced the highest fat intake and energy accretion.

Topics: Adipose Tissue; alpha-Linolenic Acid; Animals; Body Composition; Body Weight; Dietary Fats; Energy Metabolism; Fatty Acids; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids, Conjugated; Male; Mice; Mice, Inbred BALB C; Oleic Acid; Stearic Acids

A complex mixture of different lipid compounds, including phosphatidylcholine, phosphatidylserine, all trans-retinol, 15(S)-hydroperoxyeicosatetraenoic acid, D-alpha-tocopherol, saturated and unsaturated fatty acids can be separated by reversed phase HPLC by using a C-18, 120 mm x 4 mm, 3 microns particle size column and a step gradient from acetonitrile/water (1:1; v:v) to 100% acetonitrile at a flow rate of 0.8 ml/min. By applying this elution condition, separation of various groups of lipid hydroperoxides and lipid derivatives, each one originating from a different in vitro peroxidized polyunsaturated fatty acid, can be obtained. Simultaneous detection is carried out by a diode array detector at a wavelength accumulation range set up between 195 and 400 nm. The possibility of simultaneously having such a large number of measurements renders this chromatographic method particularly suitable in studies concerning lipid peroxidation where, in addition to the detection of free radical-induced lipid hydroperoxides, data on some key antioxidant molecules, i.e. vitamin A and E, as well as that of structural compounds of biological membranes, i.e. phosphatidylcholine and phosphatidylserine, can be achieved.

Topics: Acetonitriles; Arachidonic Acid; Chromatography, High Pressure Liquid; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Leukotrienes; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Lipid Peroxides; Lipids; Membrane Lipids; Oleic Acid; Palmitic Acid; Phosphatidylcholines; Phosphatidylserines; Stearic Acids; Vitamin A; Vitamin E

The objective of the present study was to investigate the effect of membrane fatty acid (FA) composition on the activity of phospholipase C (PLC) in HT-29 human colon cancer cells. The membrane FA composition was altered by supplementing cultured cells with FAs of different composition. The FAs were stearic acid (18:0; SA), gamma linolenic acid (18:3 omega 6; gamma LnA); alpha linolenic acid (18:3 omega 3; alpha LnA;); eicosapentaenoic acid (20:5 omega 3; EPA) and docosahexaenoic acid (22:6 omega 3; DHA). The fatty acids were supplemented as a FA/BSA complex. Cells supplemented with SA served as the control. Tumor growth was followed by counting the number of cells in culture. The results indicate that polyunsaturated fatty acid (PUFA) supplementation had no consistent effect on tumor growth from 1 day to another throughout the 15 days of growth. The fatty acid composition of membranes indicates that cells incorporated and modified the supplemented fatty acids by desaturation, elongation and retroconversion. The unsaturation index (UI) of membranes of cells supplemented with EPA and DHA was higher than other groups. PLC activity; measured in the absence of GTP gamma(S) in the assay mixture; was not influenced by membrane FA modification. However, in the presence of GTP gamma(S) PLC of cells supplemented with 18:3(omega 6) was the lowest among the groups. It has been shown that 18:3(omega 6) accumulated the most in the phosphatidylethanolamine (PE) fraction. There was a negative correlation between the activity of PLC in the presence of G protein activation and PE 18:3 (omega 6) content without affecting UI. It was concluded that G protein may be sensitive to the level of 18:3(omega 6) content and not to the general fluidity of the membranes.

Topics: alpha-Linolenic Acid; Animals; Cattle; Cell Membrane; Colonic Neoplasms; Dietary Fats; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids; Fatty Acids, Unsaturated; gamma-Linolenic Acid; GTP-Binding Proteins; Humans; Membrane Lipids; Neoplasm Proteins; Phosphatidylinositol Diacylglycerol-Lyase; Phosphoric Diester Hydrolases; Serum Albumin, Bovine; Signal Transduction; Stearic Acids; Tumor Cells, Cultured

The incorporation of [1-14C]linoleic and [1-14C]stearic acid and of their delta 6 and delta 9 desaturation products (gamma-linolenic and oleic acids, respectively) into different classes of lipids was studied in liver microsomes of rats in function of the diet (blackcurrant seed oil diet, containing gamma-linolenic acid, versus control diet) and in function of age (3, 6 and 9 months). After delta 6 desaturation, total radioactivity was distributed between phospholipids, especially phosphatidylcholine, and neutral lipids. The desaturation product, gamma-linolenic acid, was totally recovered in the phospholipid fraction. Blackcurrant seed oil, which decreased the rate of delta 6 desaturation in 6- and 9-month-old rats, also decreased the incorporation of radioactivity in total phospholipids, especially in phosphatidylcholine. At 6 months of age, after delta 9 desaturation, the majority of radioactivity was recovered in neutral lipids principally as oleic acid, the desaturation product. The precursor, stearic acid, was highly incorporated into phospholipids, especially in rats on a diet of blackcurrant seed oil.

Topics: Aging; Animals; Dietary Fats, Unsaturated; Fatty Acid Desaturases; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Linolenic Acids; Linoleoyl-CoA Desaturase; Lipid Metabolism; Male; Microsomes, Liver; Oleic Acid; Oleic Acids; Plant Oils; Rats; Rats, Inbred Strains; Stearic Acids; Stearoyl-CoA Desaturase

Two species of rumen bacteria that have been previously shown to partially hydrogenate alpha-linolenic acid have been examined for their ability to hydrogenate gamma-linolenic acid. Free gamma-linolenic acid is hydrogenated in vitro to stearic acid by a rumen Fusocillus sp. (N.C.I.B. 11026), but only to cis,trans-octadec-6,11-enoic acid by a Butyrivibrio sp. The sequential hydrogenations are preceded by a delta 12-cis-delta 11-trans isomerization identical with that observed in the hydrogenation of alpha-linolenic acid and linoleic acid.

Topics: Animals; Cattle; Eubacterium; Fusobacterium; gamma-Linolenic Acid; Hydrogenation; Isomerism; Linolenic Acids; Molecular Conformation; Oleic Acids; Rumen; Stearic Acids