bluuebunny/crossref_metadata_2025 huggingface dataset:
Estradiol is a potent inhibitor of the hypotriglyceridemic effect of levonorgestrel in female rats
Authors: Taves Edgar H. , Wolfe Bernard M. J.
Published: November 2006

The progestin, levonorgestrel, when administered to rats intramuscularly, significantly lowered both total and very low density lipoprotein triglyceride concentrations in the blood plasma by 35–40%. This effect was readily abolished by the simultaneous intramuscular administration of estradiol benzoate. Similarly, estradiol‐17β overcame the inhibitory effects of levonorgestrel on the incorporation of [9,10‐3H]palmitate into triglycerides of freshly isolated rat hepatocytes studiedin vitro. However, estradiol alone significantly raised plasma triglycerides by two‐foldin vivo. Estradiol also significantly enhanced (by 9%) the incorporation of [9,10‐3H]palmitate into hepatocyte triglycerides. These results suggest that the effects of estradiol on triglyceride synthesis and concentration dominate over those of levonorgestrel in the rat.
Rates of depletion of linoleic acid from fat depots of selected lines of mice differing in growth rate and adiposity
Authors: Eisen E. J. , Cartwright A. L. , Weller K. M. , Smith K. J.
Published: November 2006

Rates of depletion and half‐lives of linoleic acid from epididymal, subcutaneous and retroperitoneal fat pads and the residual body were compared among 5 genetically diverse strains of mice: M16, a polygenic obese line developed by selection for high postweaning gain; ICR, a control line from which M16 was derived; H6, a nonobese strain selected for large 6‐week body weight; L6, selected for small 6‐week body weight; and C2 a control line from which H6 and L6 were initiated. Rates of depletion and half‐lives of linoleic acid were obtained on a fat‐free diet following an enrichment period of feeding a diet high in linoleic acid. The M16 mice have an increased capability of synthesizing fat from carbohydrates as shown by a continued increase in fat depot weights when fed the fat‐free diet. The 4 other lines showed no subsequent increase in fat depot weights on the fat‐free diet. Rates of depletion of linoleic acid were significantly different among lines in each of the 4 depots. Ranking of lines for depletion rates was similar among the 3 discrete depots, but a more rapid rate of depletion was observed in subcutaneous and retroperitoneal fat depots than in the epididymal fat depot. Rates of depletion in line M16 were slower than in the ICR control line. Line H6 had a slower rate of depletion than line L6. Line L6 deviated more from the C2 control than did line H6, indicating an asymmetric correlated selection response. The decreased depletion rate of linoleic acid in fat tissue of M16 and H6 mice suggests the possibility that the turnover rates of fatty acids have been reduced in these lines as a result of a reduction in lipolytic activity. The increased depletion rate of linoleic acid in L6 mice suggests that selection for small body size has substantially increased the rate of fat turnover. The experiment demonstrates that genetic differences among lines in fat turnover have accurued as corelated responses to selection for growth rate.
Hypercholesterolemia in rats: Combined effect of high cholesterol diet and female sex steroids
Authors: Fischer G. M. , Swain M. L.
Published: November 2006

The influence of estradiol and a contraceptive steroid combination on plasma cholesterol was studied in female rats on both normal and high‐cholesterol diets which did not contain thiouracil. The high‐cholesterol diet resulted in moderate hypercholesterolemia without weight loss, even with prolonged feeding. Hypercholesterolemia was markedly accentuated in the presence of either endogenous or exogenous sex hormones.
The metabolism of phytosterols in the insectTenebrio molitor: Utilization of 24‐methylenecholesterol and 24,28‐epoxymethylenecholesterol
Authors: Nicotra Francesco , Ronchetti Fiamma , Russo Giovanni
Published: November 2006

[23,23,25‐3H3]24‐Methylenecholesterol and the corresponding 24,28‐epoxide are converted into labeled cholesterol by larvae ofTenebrio molitor.
A comparison of the biological properties of of androst‐5‐en‐3β‐ol, a series of (20R)‐n‐alkylpregn‐5‐en‐3β‐ols and 21‐isopentylcholesterol with those of cholesterol
Authors: Nes William R. , Adler John H. , Billheimer Jeffrey T. , Erickson Katherine A. , Joseph John M. , Landrey Josephine R. , Marcaccio‐Joseph Rosemarie , Ritter Karla S. , Conner Robert L.
Published: November 2006

The Δ5‐sterol, androst‐5‐en‐3β‐ol, which has no side chain at C‐17, did not permit molting of the insectHeliothis zea, growth of either the protozoanTetrahymena pyriformis, or the yeastSaccharomyces cerevisiae adapted to anaerobic conditions, nor was the sterol esterified by a mammalian microsomal ACAT preparation. However, the sterol did form a liposome with egg lecithin and, when fed to mice, did inhibit hepatic cholesterol synthesis. 21‐Isopentylcholesterol also formed a liposome but neither supported the growth of the yeast nor was metabolized by the protozoan. When sterols, 20(R)‐n‐alkylpregn‐5‐en‐3β‐ols, with side chains of varying lengths were added to the medium of the protozoan, maximal esterification with fatty acids occurred with the 20(R)‐n‐pentyl derivative, and maximal inhibition of tetrahymanol formation occurred with then‐butyl,n‐pentyl andn‐hexyl derivatives. In all of the assays, cholesterol showed a positive response, either permitting molting or growth, being metabolized, inhibiting sterol or tetrahymanol synthesis, or forming a liposome.
Association of the intestinal brush‐border membrane phospholipase A2 and lysophospholipase activities (phospholipase B) with a stalked membrane protein
Authors: Pind Steven , Kuksis Arnis
Published: November 2006

We have attempted to determine the size and membrane orientation of a recently described rat jejunal brushborder protein possessing phospholipase A2 and lysophospholipase activities (phospholipase B) (Pind, S. and Kuksis, A. [1988]Biochim. Biophys Acta 938, 211–221). The phospholipase A2 and lysophospholipase activities were renatured following nonreducing sodium dodecyl sulphate polyacrylamide gel electrophoresis of the total membrane proteins and were shown to migrate as a component of a protein band having a relative molecular mass of 170 kDa. This band accounted for approximately 1% of the total Coomassie Blue staining proteins. Phospholipase B was also shown to be solubilized from the membranes, in an active form, by a proteolytic digestion with papain. Papain solubilization resulted in a loss of the hydrophobic properties observed for the intact phospholipase. These results suggest that the active site of the phospholipase projects from the luminal surface of the membrane vesicles. In support of this, phospholipase activity towards exogenous, detergent‐solubilized phosphatidylcholine was demonstrated under conditions in which the membranes remained intact. We conclude that the phospholipase B has the characteristics of a stalked, brush‐border membrane protein and may be considered as another digestive enzyme anchored in this membrane.
1‐O‐alk‐1′‐enyl‐2‐acyl and 1‐O‐alkyl‐2‐acyl glycerophospholipids in white muscle of bonitoEuthynnus pelamis (Linnaeus)
Authors: Ohshima Toshiaki , Wada Shun , Koizumi Chiaki
Published: November 2006

The existence of ether‐linked phospholipids, including 1‐O‐alk‐1′‐enyl‐2‐acyl and 1‐O‐alkyl‐2‐acyl‐sn‐glycero‐3‐phosphocholines and ethanolamines in bonitoEuthynnus pelamis (Linnaeus) white muscle, was investigated by gas chromatography and gas chromatography‐mass spectrometry. Chemical ionization (iso‐butane) mass spectrometry of trimethylsilyl ethers derived from the corresponding ether‐linked glycerophospholipids proved effective not only for determining molecular weights but also for structural identification based on the ions [M−R]+, [M−RO]+ and [M+1]+. 1‐O‐Alk‐1′‐enyl‐2‐acyl‐sn‐glycero‐3‐phosphocholine and ethanolamine accounted for 3.0–6.0% and 3.6–7.6% of the total glycerophospholipids, respectively. 1‐O‐Alkyl‐2‐acyl‐sn‐glycero‐3‐phosphocholine and ethanolamine were also determined for one fish and accounted for 1.4% and 0.6% of the total glycerophospholipids, respectively. The predominant long chains in thesn‐1 position of the glycerol moieties were 16∶0, 18∶0 and 18∶1 in the case of the alkenylacyl and alkylacyl components. Fatty acid distribution of individual glycerophospholipids was also determined.
Changes in lipid composition of liver microsomes and fatty acyl‐CoA desaturase activities induced by medium chain triglyceride feeding
Authors: Periago José L. , Pita María L. , Sanchez del Castillo María A. , Caamaño Guillermo , Suárez María D.
Published: November 2006

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.
Molecular species of glycerophospholipids and sphingomyelins of human erythrocytes: Improved method of analysis
Authors: Myher J. J. , Kuksis A. , Pind S.
Published: November 2006

This study reports the application of modern methods of molecular species analysis in determination of the structure of both major and minor glycerophospholipids and sphingomyelins of human erythrocytes. Individual phospholipid classes were resolved from total lipid extracts by thin‐layer chromatography. Diradylglycerols were released by phospholipase C and converted into trimethylsilyl ethers, which were resolved into the alkenylacyl, alkylacyl and diacylglycerol subclasses by normal phase high performance liquid chromatography. Molecular species of diradylglycerols and ceramides were quantitated according to carbon and double bond number by gas liquid chromatography using a fused silica capillary column wall‐coated with bonded RTx‐2330. The molecular species of ceramides were determined by GC/MS. The diradyl glycerophosphocholines contained 93.0% diacyl, 4.6% alkylacyl and 2.5% alkenylacyl, white the diradyl glycerophosphoethanolamines were made up of 48.8% diacyl, 47.8% alkenylacyl and 3.4% alkylacyl subclasses. Analysis of the molecular species showed that the long chain polyunsaturated acids were mainly combined with C16 in all diradyl GPC subclasses and in diacyl GPE, while in the alkylacyl and alkenylacyl GPE and in diacyl glycerophosphoinositol and diacyl glycerophosphoserine they were combined mainly with C18 saturated fatty chains. In addition to the C16 and C18 alkyl and alkenyl, the ether fractions also contained significant proportions of C20, C22 and C24 chains. The molecular species of the ceramide moieties of the SPH were made up largely of mono‐ and diunsaturated species. Over 200 molecular species were identified and quantitated in a representative sample of human red blood cells.
Eicosapentaenoic and arachidonic acid: Comparison of metabolism and activity in murine epidermal cells
Authors: Belury Martha A. , Patrick Kelly E. , Locniskar Mary , Fischer Susan M.
Published: November 2006

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.
The hepatocellular transport of sulfobromophthalein‐glutathione by clofibrate treated, perfused rat liver
Authors: Sorrentino Dario , Weisiger Richard A. , Bass Nathan M. , Licko Vojtech
Published: November 2006

The hypolipidemic drug clofibrate is known to affect the hepatic transport of various organic anions including bilirubin, fatty acids and sulfobromophthalein. Changes in the rate of metabolism and/or intracellular transport have been claimed responsible for the effect. To evaluate these possibilities, the transport of sulfobromophthalein‐glutathione, a model compound that does not require metabolism for biliary excretion, was studied in perfused livers isolated from clofibrate‐treated and control rats. Cytosolic fatty acid binding protein and glutathione S‐transferase activity were also measured. Clofibrate treatment significantly increased liver weight; as a result glutathione S‐transferase activity (toward 1‐chloro‐2,4‐dinitrobenzene) fell if expressed per gram of liver (4560±420 (SE) vs 7010±260 nmoles/min for clofibrate treated and controls respectively, p<0.002), but was unchanged when expressed per total liver (60.8±6.5 vs 64.6±3.5 μmoles/min for clofibrate and controls p>0.5). Irrespective of how it was expressed fatty acid binding protein was significantly increased by the drug treatment. Steady state sulfobromophthalein‐glutathione removal velocity was saturble with increasing concentrations of sulfobromophthalein‐glutathione in both control and clofibrate‐treated livers. Steady state extraction ratio, as well as Vmax and Km for removal, did not differ between the two groups. In keeping with other observations, these data collectively indicate that the hepatic steady state removal of nonmetabolized compounds is not affected by clofibrate. Because the concomitant decrease in glutathione S‐transferase activity only reflects an opposite change in liver weight, it remains to be determined whether clofibrate alters the hepatic transport of sulfobromophthalein and other compounds that are conjugated with glutathione solely by changing their rate of metabolism.
Increased plasma triglyceride secretion in EFA‐deficient rats fed diets with or without saturated fat
Authors: Williams M. A. , Tinoco J. , Hincenbergs I. , Thomas B.
Published: November 2006

Metabolic responses to essential fatty acid‐deficiency in rats include an increased rate of triglyceride secretion into the plasma, a large reduction in the HDL1 plasma lipoprotein concentration, and increased concentrations of liver triacylglycerols and cholesteryl esters. Because of differences in the types of EFA‐deficient diets used, it is not clear whether these responses were solely due to the absence of EFA from the diet or whether saturated fat, or differences in acyl group chain length in this fat, might be responsible. Therefore, we fed rats diets differing only in amounts and kinds of fat, and measured triacylglycerol secretion rates and liver concentrations of triacylglycerols and cholesteryl esters, for comparison with our earlier measurements of plasma high density lipoprotein subpopulations in rats fed exactly the same diets. The purified diets contained either no fat, 5% by weight hydrogenated coconut oil, 5% hydrogenated cottonseed oil, or each of these three diets supplemented with 1% safflower oil, or 5% corn oil. We also fed some rats a nonpurified stock diet for comparison with literature reports. The present results indicate that the metabolic responses to essential fatty acid deficiency described above are definitely due to essential fatty acid‐deficiency and not to the presence or chain length of acyl groups in saturated fat in the diet.
The precursors of fecapentaenes: Purification and properties of a novel plasmalogen
Authors: Van Tassell R. L. , Piccariello T. , Kingston D. G. I. , Wilkins T. D.
Published: November 2006

Fecapentaene‐12 and fecapentaene‐14 are genotoxic polyunsaturated ether‐lipids produced by the colonic microflora in humans and pigs. Although the fecapentaenes have been extensively characterized, little is known about the nature of the precursors from which they are produced. We purified one form of these precursors from feces of an individual who excreted high levels of fecapentaene‐12 and its precursors. Purification was carried out by a series of extractions and precipitation in organic solvents followed by silica and amine high performance liquid chromatography. The purified precursor had identical UV spectral characteristics as the fecapentaenes indicating that it contained the same ether‐linked pentaenyl functional group. However, it was not mutagenic. The precursor was amphiphilic in nature, behaving like a synthetic “model” ether‐phospholipid on silica and C18 thin layer chromatography. When incorporated into phosphatidylcholine micelles it could be hydrolyzedin vitro by a combination of lipase and phospholipase C to fecapentaene‐12. Our findings indicate that the general structure of this precursor is that of a phospholipid, specifically a plasmalogen—the exact structures of which remain to be determined.
Fatty acid hydroperoxide isomerase inSaprolegnia parasitica: Structural studies of epoxy alcohols formed from isomeric hydroperoxyoctadecadienoates
Authors: Hamberg Mats
Published: November 2006

The major part (80%) of the fatty acid hydroperoxide isomerase activity present in homogenates of the fungus,Saprolegnia parasitica, was localized in the particle fraction sedimenting at 105,000×g.

13(S)‐Hydroperoxy‐9(Z),11(E)‐octadecadienoic acid and 9(S)‐hydroperoxy‐10(E),12(Z)‐octadecadienoic acid were both good substrates for the particle‐bound hydroperoxide isomerase. The products formed from the 13(S)‐hydroperoxide were identified as an α,β‐ and a γ,δ‐epoxy alcohol, i.e., 11(R),12(R)‐epoxy‐13(S)‐hydroxy‐9(Z)‐octadecenoic acid and 9(S),10(R)‐epoxy‐13(S)‐hydroxy‐11(E)‐octadecenoic acid, respectively. The 9(S)‐hydroperoxide was converted in an analogous way into an α,β‐epoxy alcohol, 10(R),11(R)‐epoxy‐9(S)‐hydroxy‐12(Z)‐octadecenoic acid and a γ,δ‐epoxy alcohol, 12(R),13(S)‐epoxy‐9(S)‐hydroxy‐10(E)‐octadecenoic acid.

9(R,S)‐Hydroperoxy‐10(E),12(E)‐octadecadienoic acid and 13(R,S)‐hydroperoxy‐9(E),11(E)‐octadecadienoic acid were poor substrates for theS. parasitica hydroperoxide isomerase. Experiments with 13(R,S)‐hydroperoxy‐9(Z),11(E)‐octadecadienoic acid showed that the 13(R)‐hydroperoxy enantiomer was slowly isomerized by the enzyme. The major product was identified as α,β‐epoxy alcohol 11(R),12(R)‐epoxy‐13(R)‐hydroxy‐9(Z)‐octadecenoic acid.
Polyunsaturated fatty acid changes suggesting a new enzymatic defect in Zellweger Syndrome
Authors: Martinez Manuela
Published: November 2006

The fatty acid composition of red blood cells, fibroblasts, forebrain, liver and kidney were studied in a 3‐month‐old infant who died from Zellweger Syndrome, and the results were compared with those of age‐matched controls. Besides a typical increase in the very long chain fatty acids 26∶0 and 26∶1 and a great reduction in the plasmalogen levels, confirming the diagnosis of Zellweger Syndrome, some striking changes in the polyunsaturated fatty acid patterns were discovered. The most important was a very drastic decrease in the values of 22∶6ω3 and 22∶5ω6, the two products of Δ4‐desaturation. In the kidney, the level of 22∶6ω3 fell below that of 26∶0. Consequently, the ratio 26∶0/22∶6ω3 (and 26∶1/22∶6ω3) was most useful in emphasizing the fatty acid anomalies, especially in renal tissue, where the 26∶0/22∶6ω3 ratio increased to almost 200 times the normal values. Other significant, although less consistent fatty acid alterations were increases in 18∶2ω6, 18∶3ω6, 20∶3ω6, 18∶4ω3 and 20∶4ω3, and a decrease in 20∶4ω6 in some tissues. The existence is proposed of a new enzyme defect in peroxisomal disorders, involving the desaturase system of long chain polyunsaturated fatty acids.
Oxidation of vitamin E in red cell membranes by fatty acids, hydroperoxides and selected oxidants
Authors: Vatassery G. T.
Published: November 2006

Our laboratory previously reported that vitamin E (tocopherol) in human blood platelets was oxidizedin vitro by various oxidants. This paper shows that diamide, superoxide, hydroperoxides and polyunsaturated fatty acids induced oxidation of tocopherols in red cell membranes. In contrast to platelets, red cell membrane tocopherol was oxidized by hydrogen peroxide and tertiary butyl hydroperoxide. Alpha tocopherolquinone was one of the products of oxidation. Among the fatty acids, thecis polyunsaturated acids were the most potent oxidizing agents with monounsaturated andtrans compounds relatively ineffective. The oxidation is not a detergent effect of the fatty acids since neither the detergents Brij and Lubrol, when present in concentrations under 0.5 mM, nor sodium arachidate (1.25 mM), could oxidize the membrane tocopherol. When red cell membrane samples were incubated with 0.5 mM arachidonate, 47±11% (S.D.) of the tocopherol lost was converted to tocopherolquinone. Unlike arachidonate, oxidants such as diamide, hydrogen peroxide and tertiary butylhydroperoxide are unable to oxidize all of the membrane tocopherol and produce less tocopherolquinone from oxidation (10–15%) under the experimental conditions of this study. Linoleic acid hydroperoxide is a much more potent oxidant and produces less quinone than arachidonate. The mechanisms of tocopherol oxidations induced by the various compounds seem to be different since the yields of quinone during oxidation vary with the nature of the oxidant. Tocopherol is consumed by oxidation as it protects the membrane from oxidant damage induced by compounds such as unsaturated fatty acids and hydroperoxides.
Environmental temperature and metabolism of the molecular species of phosphatidylcholine in the tissues of the rainbow trout
Authors: Malak Nabil Abdul , Brichon Gerard , Meister Roger , Zwingelstein Georges
Published: November 2006

The phospholipid composition and the fatty acid pattern of phosphatidylcholine from major tissues of the rainbow trout acclimated to 11° and 21°C were analyzed. A significant difference in the level of 20∶5ω3 fatty acid between gill, kidney, intestine and liver phosphatidylcholine is observed in both groups of animals. These differences correlate with a modification of the molecular species distribution in the phosphatidylcholine in these organs. In vivo incorporation of32P into phospholipids of gills, kidney, intestine, liver and muscle was determined in trout acclimated to 11° and 21°C. Temperature acclimation specifically modify the relative specific radioactivity of the monoene and hexaene molecular species of phosphatidylcholine in gills, intestine, kidney and liver. It can be concluded from these results, that the metabolism of the diacylglycerol moiety and the coupled fatty acids of phosphatidylcholine differs with the tissue and the temperature. It is suggested that different associated mechanisms specific for each organ determine the fatty acid composition of phophatidylcholine required for its physiological functions at each temperature.
Sterol metabolism in the nematodePanagrellus redivivus
Authors: Salt Thomas A. , Chitwood David J. , Lusby William R.
Published: November 2006

Panagrellus redivivus was propagated in media containing three structurally different sterols: 7‐dehydrocholesterol, campesterol or stigmastanol. Nematodes propagated with 7‐dehydrocholesterol contained mostly lathosterol and 7‐dehydrocholesterol. Nematodes propagated with campesterol contained mostly cholesterol and cholestanol. Nematodes propagated with stigmastanol contained mostly cholestanol. The sterol ester fraction was enriched with 4α‐methylsterols and contained the same sterols as the free sterol fraction except for nematodes propagated with 7‐dehydrocholesterol, where no dietary sterol was found in the ester fraction.P. redivivus is capable of reducing the Δ5‐bond, C−24 dealkylation and methylating the sterol nucleus at C−4.
Dietary saturated fat level alters the competition between α‐linolenic and linoleic acid
Authors: Garg M. L. , Wierzbicki A. A. , Thomson A. B. R. , Clandinin M. T.
Published: November 2006

Male weanling rats were fed semi‐synthetic diets high in saturated fat (beef tallow) vs high in linoleic acid (safflower oil) with or without high levels of α‐linolenic acid (linseed oil) for a period of 28 days. The effect of feeding these diets on cholesterol content and fatty acid composition of serum and liver lipids was examined. Feeding linseed oil with beef tallow or safflower oil had no significant effect on serum levels of cholesterol. Serum cholesterol concentration was higher in animals fed the safflower oil diet than in animals fed the beef tallow diet without linseed oil. Feeding linseed oil lowered the cholesterol content in liver tissue for all dietary treatments tested. Consumption of linseed oil reduced the arachidonic acid content with concomitant increase in linoleic acid in serum and liver lipid fractions only when fed in combination with beef tallow, but not when fed with safflower oil. Similarly, ω3 fatty acids (18∶3ω3, 20∶5ω3, 22∶5ω3, 22∶6ω3) replaced ω6 fatty acids (20∶4ω6, 22∶4ω6) in serum and liver lipid fractions to a greater extent when linseed oil was fed with beef tallow than with safflower oil. The results suggest that the dietary ratio of linoleic acid to saturated fatty acids or of 18∶3ω3 to 18∶2ω6 may be important to determine the cholesterol and arachidonic acid lowering effect of dietary α‐linolenic acid.
On‐line hydrogenation in GC‐MS analysis of cyclic fatty acid monomers isolated from heated linseed oil
Authors: Le Quéré J. L. , Sémon E. , Lanher B. , Sébédio J. L.
Published: November 2006

A simple on‐line hydrogenation method in GC‐MS analysis of unsaturated fatty acid esters is described. Using hydrogen as carrier gas, hydrogenation takes place in a capillary reactor connected to the outlet of the analytical column in the oven of the gas chromatograph. The reactor is a fused silica tube (60 cm×0.32 mm i.d.) coated with palladium acetylacetonate. Selective hydrogenation of olefinic bonds is achieved after a normal chromatographic run. Structural information (carbon‐skeleton, double bond equivalents) can thus be deduced, and structural correlations between the saturated and unsaturated components can be obtained. Structures of cyclic fatty acid esters isolated from heated linseed oil were elucidated using this simple method which was found very useful for structural investigations on unsaturated compounds by GC‐MS.
The effect of dietary fish oil on muscle and adipose tissue lipoprotein lipase
Authors: Herzberg Gene R. , Rogerson Maria
Published: November 2006

The activity of lipoprotein lipase (LPL) in the adipose tissue and skeletal muscle of rats fed glucose‐ or fructose‐based diets containing fish oil, corn oil or tallow was examined. In addition, heart LPL activity was measured in rats fed a glucose‐based diet containing either corn oil or fish oil. Adipose tissue LPL activity was unaffected by dietary fat. In both heart and skeletal muscle, LPL activity was higher in rats fed the fish oil diet. These results suggest that increased removal of triglyceride by muscle may contribute to the blood triglyceride lowering effect of dietary fish oil.
Isolation and characterization of ganglioside 9‐O‐acetyl‐GD3 from bovine buttermilk
Authors: Bonafede Daniela M. , Macala Lawrence J. , Costantine‐Paton Martha , Yu Robert K.
Published: November 2006

Bovine buttermilk contains a unique ganglioside, 9‐O‐acetyl‐GD3. In order to isolate large quantities of this ganglioside, a simplified isolation scheme which consists of several ion‐exchange and silica gel column chromatographic procedures was devised. The isolated 9‐O‐acetyl‐GD3 was characterized on the basis of its thin‐layer chromatographic behavior, its immunoreactivity with a specific monoclonal antibody, JONES, and by conversion to authentic GD3 by mild base treatment.
Lipid characteristics of RSV‐transformed Balb/c 3T3 cell lines with different spontaneous metastatic potentials
Authors: Calorini Lido , Fallani Anna , Tombaccini Donatella , Barletta Emanuela , Mugnai Gabriele , Di Renzo Maria F. , Comoglio Paolo M. , Ruggieri Salvatore
Published: November 2006

To determine whether a metastatic phenotype may be corelated with a characteristic lipid pattern, we compared the lipid composition of low metastasizing Balb/c 3T3 cells transformed by the B77 strain of Rous sarcoma virus (B77‐3T3 cells) with that of a subclone isolated by growth in 0.6% agar, the B77‐AA6 cells, which exhibit a high capacity for spontaneous metastasis. B77‐3T3 cells revealed characteristics in their lipid composition common to other systems of transformed cells, i.e., an accumulation of ether‐linked lipids, a reduction of the more complex gangliosides, an increase of oleic acid (18∶1) and a decrease of arachidonic (20∶4) and C22 polyunsaturated fatty acids in phospholipids. High metastatic B77‐AA6 cells showed: a) an even more marked decrease of complex gangliosides; b) a more pronounced increase of 18∶1 and decrease of 20∶4 and 22 polyunsaturated fatty acids in certain phospholipid classes; and c) a higher percentage of alkyl‐acyl subfractions in both phosphatidylcholine and phosphatidylethanolamine than B77‐3T3 cells.

Comparing the data for other systems of metastatic cells with those of lipid studies of spontaneously metastasizing B77‐AA6 cell system leads us to conclude that the metastatic phenotype is characterized by a change in ether‐linked lipids, rather than in fatty acids.
An evaluation of NBD‐phospholipids as substrates for the measurement of phospholipase and lipase activities
Authors: Moreau Robert A.
Published: November 2006

Because most of the existing assays of phospholipase activity are quite laborious, the use of 1‐acyl‐2‐[6‐(7‐nitro‐1,3‐benzoxadiazol‐4‐yl)amino]caproyl labeled phospholipids (NBD phospholipids) was investigated to determine whether they could be used as substrates in the routine assay of various phospholipases and lipases. NBD‐labeled analogues of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid were evaluated. There was about a 50‐fold increase in fluorescence upon hydrolysis of the NBD hexanoic acid from the NBD phospholipid, confirming an earlier report. This change in fluorescence was constant over the normal physiological pH range (pH 5–9). Detergents and bovine serum albumin interfered with the assay in a concentration dependent manner. An increase in fluorescence and a concomitant increase in NBD hexanoic acid was detected with the two phospholipase A2 enzymes. Although a change in fluorescence was detected with a phospholipase C, careful evaluation revealed that the rate of increase in fluorescence was not proportional to the rate of production of diacylglycerol product. Neither of the two phospholipase D enzymes which were tested were able to cause an increase in fluorescence when incubated with NBD phospholipids. A small increase in fluorescence was detected with each of the four lipases. Of the five NBD lipids tested, the highest rates of hydrolysis were consistently obtained with NBD‐phosphatidylglycerol followed by NBD‐phosphatidylcholine.
Activation of rat liver cholesterol ester hydrolase by cAMP‐dependent protein kinase and protein kinase C
Authors: Ghosh Shobha , Grogan W. McLean
Published: November 2006

Short term regulation of hepatic cholesterol ester hydrolase by reversible phosphorylation is described. Two different kinase systems seem to be involved in this regulation. The addition of ATP, cyclic AMP and Mg2+ to rat liver 104,000× g supernatant (S104) produced a 100–140% increase in cholesterol ester hydrolase activity. This stimulation was abolished when protein kinase inhibitor was added prior to the addition of ATP, cyclic AMP and Mg2+. Cholesterol ester hydrolase activity was also stimulated when calcium ions, phosphatidylserine, and diolein were added to S104 along with ATP and Mg2+. Diolein in this reaction could be substituted by phorbol 12‐myristate 13‐acetate. Preincubation of S104 with alkaline phosphatase resulted in a deactivation of cholesterol ester hydrolase. The addition of increasing concentrations of Mg2+ to S104 produced increasing inhibition of cholesterol ester hydrolase activity, and this effect was blocked by NaF.

It is suggested that rat liver cholesterol ester hydrolase is activated by cyclic AMP dependent protein kinase and protein kinase C. Deactivation is accomplished by dephosphorylation catalyzed by a phosphoprotein phosphatase, dependent on Mg2+.
α‐Oxidation of α‐hydroxyfatty acids in rat brain. Possible involvement of an α‐peroxylactone
Authors: Salim‐Hanna Marta , Campa Ana , Cilento Giuseppe
Published: November 2006

Combine—but not individual—microsomal and supernatant fractions obtained from rat brains not only consume oxygen but also provoke emission from added chlorophyll. These results are consistent with literature data (Levis and Mead,J. Biol. Chem. 239, 77 [1964]) for trapping of radioactive14CO2 following addition of α‐hydroxy‐[1‐14C]stearic acid. The most plausible explanation for emission is the interaction of chlorophyll with an α‐peroxylactone. An intermediary α‐peroxylactone in α‐oxidation is consistent with other available data (Salim‐Hanna, Campa and Cilento,Photochem. Photobiol. 45, 849 [1987]; Campa, Salim‐Hanna and Cilento,Photochem. Photobiol. 49, 349 [1989]) and, on chemical grounds, provides a feasible route to the final products.
Incorporation of arachidonic, dihomogamma linolenic and eicosapentaenoic acids into cultured V79 cells
Authors: Weithmann Klaus U. , Peterson Hazel , Sevanian Alex
Published: November 2006

The uptake and distribution of three common dietary polyunsaturated fatty acids was studied using Chinese hamster lung fibroblasts (V79 cells). Treatment of V79 cells with arachidonic (20∶4), eicosapentaenoic (20∶5) and dihomogammalinolenic (20.3) acids for 24 hr produced a marked uptake of 20∶3 and 20∶4, both of which were assimilated to a considerably greater degree than 20∶5. All polyunsaturated fatty acids were incorporated primarily into phospholipids; however, there were considerable differences in their distribution into individual phospholipid species. Although 20∶4 was incorporated primarily into phosphatidylcholine, 20∶3 entered largely into phosphatidylethanolamine and phosphatidylglycerol, and 20∶5 was distributed about equally between phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol. A marked conversion of 20∶3 to 20∶4 was found after 24 hr and, in several phospholipids, there was as much derived‐radiolabeled 20∶4 as there was radiolabeled 20∶3. There was little evidence of 20∶4 and 20∶5 metabolism. V79 cells undergo substantial changes in phospholipid fatty acid composition following supplementation with these polyunsaturated fatty acids; however, these fatty acids are assimilated to different degrees and their distribution among cellular phospholipids is distinct, suggesting incorporation via independent mechanisms.
Effects of fish oil, corn oil and lard diets on lipid peroxidation status and glutathione peroxidase activities in rat heart
Authors: Nalbone Gilles , Leonardi Jeannie , Termine Elise , Portugal Henri , Lechene Paulette , Pauli Anne‐Marie , Lafonf Huguette
Published: November 2006

In this study, we investigated the effect of various types of fats on heart lipid peroxidation status and on blood lipid parameters. Rats were fed either a low‐fat diet (2.2% lard plus 2.2% corn oil), a corn oil diet (17%), a salmon oil diet (12.5%) supplemented with 4.5% corn oil, or a lard diet (15%) supplemented with 2% corn oil. All diets were supplemented with 1% cholesterol. Rats were fed for eight weeks. When compared with the low‐fat diet, the salmon oil‐diet intake resulted in a lower blood cholesterol, triglyceride and phospholipid concentrations (−50, −56 and −30%, respectively). Corn oil only tended to lower blood lipids; this decrease was significant for triglycerides only (−40%). The hypocholesterolemic effect of salmon oil diet is even more pronounced, if blood cholesterol values are compared with those of rats fed the lard diet. Heart lipid composition was not affected by dietary manipulations. Fatty acid composition of cardiac phosphatidylcholines and phosphatidylethanolamines, however, were altered by high‐fat diets. In phosphatidylcholine, salmon oil induced a twelvefold decrease in the n−6/n−3 ratio and a 26% increase in the unsaturation index. For phosphatidylethanolamine, the n−6/n−3 ratio decreased 7.7‐fold and the unsaturation index increased by 13%. A 50% decrease of the n−6/n−3 ratio was observed in animals fed the lard diet. Ultramicroscopic examination of ventricles revealed that those of the salmon oil group significantly accumulated lipofuscin‐like or ceroid material, whereas this accumulation was barely detectable in hearts of the other groups. Seleniumdependent glutathione peroxidase activity tended to be the highest in hearts of rats fed the salmon oil diet; this increase is significant (+36% and +54% for total and specific activities, respectively), if values are compared with those of the rats fed the lard diet. Liver glutathione peroxidase and heart glutathione S‐transferases activities remained unchanged. These results indicate that fish oil did not lower the selenium involved in glutathione peroxidase activity. This rules out that a deficiency in this enzyme was at the origin of heart lipofuscinosis. Also, it is concluded that the n−6/n−3 ratio of the diet is likely more determinant in the alteration of heart lipid peroxidation status than is the polyunsaturated/saturated ratio.
Isolation and identification of acetyl‐CoA carboxylase from rainbow trout (Salmo gairdneri) liver
Authors: McKim J. M. , Schaup H. W. , Marien K. , Selivonchick D. P.
Published: November 2006

Acetyl‐CoA carboxylase is the pivotal enzyme in the de novo synthesis of fatty acids and is the only carboxylase with a biotin‐containing subunit greater than 200,000 daltons. The biotin moiety is covalently linked to the active site and has a high affinity (Kd=10−15 M) for the protein avidin. This relationship has been used in previous studies to identify acetyl‐CoA carboxylase isolated from mammalian species. However, acetyl‐CoA carboxylase has not been isolated and characterized in a poikilothermic species such as the rainbow trout. The present study describes the isolation and identification of acetyl‐CoA carboxylase in the cytosol of rainbow trout (Salmo gairdneri) liver. The enzyme was isolated using two distinct procedures—polyethylene glycol precipitation and avidin‐Sepharose affinity chromatography. Identification of the isolated protein as acetyl‐CoA carboxylase was made by the following: (1) sodium dodecyl sulfate‐polyacrylamide gel electrophoresis; (2) avidin binding; (3) in vivo labeling with [14C]biotin; and (4) acetyl‐CoA carboxylase‐specific activity. The subunit molecular weight of the major protein was 230,000 daltons ±3.3%. This protein was shown to bind avidin (Mr=16,600) prior to sodium dodecyl sulfate‐polyacrylamide gel electrophoresis, indicating the presence of biotin. In addition, protein isolated from fish that had previously received intraperitoneal injections of [14C]biotin, showed the majority of radioactivity associated with the 230,000 dalton protein. The polyethylene glycol precipitation yielded 200 μg protein (4.4 μg/g liver), with a specific activity of 5 nmol malonyl‐CoA/min/mg protein, whereas avidin affinity chromatography yielded 1.75±1.1 mg protein (9.0 μg/g liver), with a specific activity of 1.37±0.18 μmol malonyl‐CoA/min/mg protein. The enzyme was citrate dependent showing maximum activity between 10 and 20 mM. Acetyl‐CoA carboxylase‐specific activity decreased by 50% in the presence of 0.2 M NaCl. These findings suggest that the major protein (Mr=230,000) purified from rainbow trout liver is acetyl‐CoA carboxylase with enzyme characteristics comparable to mammalian acetyl‐CoA carboxylase.
Reaction products of α‐tocopherol with a free radical initiator, 2,2′‐azobis(2,4‐dimethylvaleronitrile)
Authors: Yamauchi Roy , Matsui Tomoatsu , Satake Yasuko , Kato Koji , Ueno Yoshimitsu
Published: November 2006

α‐Tocopherol wss reacted with an alkylperoxyl radical at 37°C in ethanol. 2,2′‐Azobis(2,4‐dimethylvaleronitrile) was used to generate the alkylperoxyl radicals. The reaction products of α‐tocopherol were isolated by reverse‐phase and normal‐phase high performance liquid chromatography, and their structures were characterized by infrared, ultraviolet,1H and13C nuclear magnetic resonances and mass spectrometry. They were 8aS‐hydroperoxy‐α‐tocopherone, 8aR‐hydroperoxy‐α‐tocopherone, a mixure of 7,8‐epoxy‐8aS‐ethoxy‐α‐tocopherone, and 7,8‐epoxy‐8aR‐ethoxy‐α‐tocopherone, 8aS‐(1R‐cyano‐1,3‐dimethyl)butylperoxy‐α‐tocopherone, 8aS‐(1S‐cyano‐1,3‐dimethyl)butylperoxy‐α‐tocopherone, a mixture of 8aR‐(1S‐cyano‐1,3‐dimethyl)butylperoxy‐α‐tocopherone and 8aR‐(1S‐cyano‐1,3‐dimethyl)butylperoxy‐α‐tocopherone, 4aR,5S‐epoxy‐8aS‐ethoxy‐α‐tocopherone, 4aS,5R‐epoxy‐8aS‐ethoxy‐α‐tocopherone and 4aR,5S‐epoxy‐8aR‐ethoxy‐α‐tocopherone.
The distribution of lipids and sterols in cell types from the marine spongePseudaxinyssa sp
Authors: Zimmerman Mary P. , Thomas Frances C. , Thompson Janice E. , Djerassi Carl , Streiner Heidi , Evans Elizabeth , Murphy Peter T.
Published: November 2006

The spongePseudaxinyssa sp., unique in sterol and fatty acid composition, was cellularly dissected into fractions enriched in each of the major cell types present in the sponge: microbial symbionts (cyanobacteria), small sponge cells (pinacocytes and choanocytes), and large sponge cells (archeocytes and cyanophytes). Three phototrophic microbial symbionts were also isolated from the cell fractions and grown in culture. An unsymmetrical distribution of fatty acids and sterols was observed for the sponge cells: small cells contained larger quantities of long chain fatty acids (> C24) and smaller quantities of sterols than were present in the larger sponge cells. Moreover, the rare sterols 24‐isopropylcholesterol predominated in the smaller sponge cells, whereas its 22‐dehydro analog predominated in the larger sponge cells. Long chain fatty acids and sterols were not detected in the cultured microbial symbionts. This constitutes the first report of lipid variability according to cell type for this most primitive group of Metazoa.
2‐Hydroxy fatty acids from marine sponges 2. The phospholipid fatty acids of the caribbean spongesVerongula gigantea andAplysina archeri
Authors: Carballeira Nestor M. , Shalabi Fathi , Negron Vilmary
Published: November 2006

The α‐hydroxy fatty acids 2‐hydroxy‐eicosanoic (1) acid, 2‐hydroxyheneicosanoic (2) acid, 2‐hydroxydocosanoic (3) acid, 2‐hydroxytetracosanoic (4) acid, 2‐hydroxy‐23‐methyl‐tetracosanoic acid and 2‐hydroxypentacosanoic (5) acid were isolated from the Caribbean spongesVerongula gigantea andAplysina archeri. The very long chain fatty acids 5,9‐nonacosadienoic acid (29∶2) and 5,9,23‐tricontatrienoic acid (30∶3) were also identified together with theiso‐prenoid fatty acid 3,7,11,15‐tetramethylhexadecanoic (phytanic) acid that seems to be common in the Aplysinidae.A. archeri contained an extremely long chain fatty acid tentatively characterized as dotricontaenoic (32∶1) acid. These acids were found to occur in phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylcholine and traces of phosphatidylglycerol.
Effect of dietary fat on individual long‐chain fatty acyl‐CoA esters in rat liver and skeletal muscle
Authors: Ney Denise M. , Lasekan John B. , Spennetta Terry , Grahn Mike , Shrago Earl
Published: November 2006

The effect of dietary fat on the long‐chain acyl‐CoA ester profile of liver and skeletal muscle was investigated by feeding weanling rats 12%‐fat diets composed of high‐linoleic safflower oil (73% 18∶2n−6), high‐oleic safflower oil (70% 18∶1n−9) or olive oil (70% 18∶1n−9) for six and ten weeks. Approximately 50% of both hepatic and skeletal muscle acyl‐CoA esters comprised linoleoyl‐CoA or oleoyl‐CoA with high‐linoleic or oleic feeding, respectively. Total hepatic acyl‐CoA ester concentration was 40% higher (p<0.05) in rats fed 12% fat compared with controls fed a 4%‐fat diet. These data demonstrate that the long‐chain acyl‐CoA ester profile of liver and skeletal muscle reflects the dietary fatty acid profile.
Vitamin E. Deficiency increases the synthesis of platelet‐activating factor (PAF) in rat polymorphonuclear leucocytes
Authors: Fukuzawa Kenji , Kurotori Yasuhiro , Tokumura Akira , Tsukatani Hiroaki
Published: November 2006

Vitamin E deficiency was found to stimulate FMLP (N‐formyl‐L‐methionyl‐L‐leucyl‐L‐phenylalanine)‐induced biosynthesis of PAF (1‐O‐alkyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine) in polymorphonuclear leucocytes (PMN) from rat peritoneum. In three separate experiments each, the amounts of PAF synthesized during 6min and 12 min incubation of PMN cells from control, vitamin E‐supplemented, and vitamin E‐deficient rats were 129–240, 131–227 and 248–354 pmol/106 cells, respectively. The activity of the acetyl‐transferase, which transfers the acetyl moiety of [3H]acetyl‐CoA to 2‐lysoPAF (1‐O‐alkyl‐sn‐glycero‐3‐phosphocholine) to form [3H]PAF, was higher in PMN homogenates from vitamin E‐deficient rats (2.28±0.07 nmol/min/mg protein) than in those from E‐supplemented rats (1.06±0.10 nmol/min/mg protein). However, there was no difference between the two groups in the activity of acetylhydrolase (4.26±0.71 and 4.26±0.06 nmol/min/mg protein, respectively), measured as degradation of [3H]PAF to [3H]lysoPAF.In vitro addition of α‐tocopherol did not inhibit the increased activity of acetyl‐transferase in vitamin E‐deficient rats, in‐dicating that the enzyme in vitamin E‐supplemented rats was not directly inhibited by α‐tocopherol. The acetyltransferases of the two groups showed similar Km values for acetyl‐CoA, but different Vmax values (225 μM and 6.4 nmol/min/mg protein in vitamin E‐deficient rats, and 216 μM and 3.6 nmol/min/mg protein in vitamin E‐supplemented rats), suggesting that the enzyme was not activated but increased in amount in vitamin E deficiency.