bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of a sterol auxotroph derived fromSaccharomyces cerevisiae on chemically synthesized derivatives of cholesterol possessing side‐chain modifications
Authors: Rodriguez R. J. , Arunachalam T. A. , Parks L. W. , Caspi E.
Published: December 2006

A number of cholesterol derivatives were analyzed for their ability to satisfy bulk membrane and high‐specificity sparking requirements of a yeast sterol auxotroph (RD5‐R) (Rodriguez, R. J., Taylor, F. R., and Parks, L. W. [1982], Biochem. Biophys. Res. Commun. 106, 435–441). Substitution of hydrogen by bromine or iodine at C‐26 or substitution of C26‐methyl by bromine enabled the resulting sterol to satisfy bulk or sparking functions. The presence of a side‐chain hydroxyl or keto group at C‐25 on a 26‐norcholesterol completely abolished the ability of cholesterol to satisfy either sterol requirement. Growth studies revealed that, while the oxygenated cholesterol derivatives were not growth‐supportive of RD5‐R, they were not growth‐inhibitory.
Fatty acid composition of triglycerides from adipose tissue transplanted between obese and lean mice
Authors: Enser Michael , Ashwell Margaret
Published: December 2006

The subcutaneous adipose tissue of genetically obese mice (ob/ob) differs from that of lean litter‐mates not only by virtue of its larger cells but also in its fatty acid composition; it contains a higher proportion of palmitoleic acid and a lower proportion of linoleic acid. To determine whether these differences in fatty acid composition were inherent in fat cells, subcutaneous adipose tissue from obese and lean mice was transplanted under the kidney capsules of lean and obese host mice and the fatty acid composition of the neutral lipids of the graft and of the host perirenal and subcutaneous fat was determined 1 or 2 months later. The fatty acid composition of grafts from lean donors in obese mice resembled that of the perirenal adipose tissue of the obese hosts after 1 month, with a lower proportion of linoleic acid and a higher proportion of palmitoleic acid than in lean mice. Grafts from obese mice in lean mice had fatty acid compositions which were either unchanged, partially changed or which completely resembled that of the host. The use of grafts prelabeled by feeding the donor margaric acid indicated that total lack of fatty acid turnover, rather than selective metabolic processes, was responsible for the failure of some grafts from obese mice in lean mice to acquire the fatty acid composition of the perirenal adipose tissue of the host.
Effect of dietary fatty acids on Δ5 desaturase activity and biosynthesis of arachidonic acid in rat liver microsomes
Authors: De Gómez Dumm I. N. T. , De Alaniz M. J. T. , Brenner R. R.
Published: December 2006

The effect of different fatty acids supplemented to a fat‐free diet on the activity of Δ5 desaturase was studied. Fat‐free diet produces a reduction in the conversion of eicosa‐8,11,14‐trienoic acid to arachidonic acid. The addition of thecis‐ω6 acids, linoleic, γ‐linolenic or arachidonic to the diet produces an increase of eicosatrienoic acid desaturation, shifting Δ5 desaturase activity towards the controls on a balanced diet. This reactivation is apparently produced by induction of enzyme biosynthesis since linoleate effect was suppressed by simultaneous cycloheximide injection. On the contrary, no changes in Δ5 desaturation activity were found when the diet was supplemented with palmitic or 9‐trans,12‐trans‐linoleic acid. The changes on the activity of Δ5 desaturase were compared with the fatty acid composition of plasma and liver microsomes.
Effect of bile acid feeding on hepatic steroid 12 α‐hydroxylase activity in hamsters
Authors: Kuroki Syoji , Hoshita Takahiko
Published: December 2006

The effects of feeding cholic acid, chenodeoxycholic acid and ursodeoxycholic acid on the activity of the hepatic steroid 12α‐hydroxylase, gallbladder bile acid composition, fecal neutral sterol output, cholesterol synthesis and bile acid synthesis were determined in female hamsters. The 12α‐hydroxylase activity was inhibited to 56% by cholic acid, to 62% by chenodeoxycholic acid, and to 78% by ursodeoxycholic acid compared with the control. Bile acid composition was altered by feeding of cholic acid and chenodeoxycholic acid to be rich in the given bile acids. Fecal neutral sterol output increased about twice by feeding chenodeoxycholic acid and ursodeoxycholic acid, whereas cholic acid had no significant effect. Body cholesterol synthesis increased to 217% by chenodeoxycholic acid and to 274% by ursodeoxycholic acid, whereas effect of cholic acid was not significant. Bile acid synthesis was suppressed to 48% of control only by chenodeoxycholic acid. A positive correlation between the 12α‐hydroxylase activity and the bile acid synthesis was observed in the control, chenodeoxycholatefed and ursodeoxycholate‐fed animals. In conclusion, ursodeoxycholic acid might have less inhibitory effect on the steroid 12α‐hydroxylase and the bile acid synthesis than chenodeoxycholic acid.
Comparison of ultracentrifugation and gel filtration for the isolation of bovine lipoproteins
Authors: Grummer R. R. , Davis C. L. , Hegarty H. M.
Published: December 2006

Lipoproteins from the plasma of three nonlactating Holstein cows were isolated using either preparative ultracentrifugation or gel filtration chromatography. Lipoprotein classes obtained by ultracentrifugation were very low density plus chylomicra, <1.006 g/ml; low density, 1.007–1.039 g/ml; high density1, 1.040–1.063 g/ml; and high density, 1.064–1.22 g/ml. These lipoprotein classes were individually applied to an agarose gel column to determine at what volume they eluted in comparison to lipoproteins that were separated after applying total bovine lipoproteins to the column. Three major peaks corresponding to very low density lipoproteins plus chylomicra, low density, and high density lipoproteins resulted after gel filtration of total lipoproteins. Very low density lipoproteins plus chylomicra, obtained by ultracentrifugation, eluted as a single peak, as did low density and high density lipoproteins. However, high density1 lipoproteins eluted as two peaks. The first peak eluted at the same volume as low density lipoproteins, and the second peak eluted at a volume similar to that of the ascending slope of the high density lipoprotein peak. Results from disc polyacrylamide gel electrophoresis, immunoelectrophoresis and double immunodiffusion of lipoprotein fractions, and SDS polyacrylamide gel electrophoresis of their apoproteins, similarly indicated that the lipoproteins present in the 1.040–1.063 g/ml density interval are a mixture of low and high density lipoproteins rather than a unique class of lipoproteins.
Metabolism of fatty acid, glycerol and a monoglyceride analogue by rat cardiac myocytes and perfused hearts
Authors: Tamboli Ashlesha , Maten Mary Vander , O'Looney Patricia , Vahouny George V.
Published: December 2006

Studies have been conducted on the uptake and metabolism of unesterified fatty acid, free glycerol and 1‐hexadecyl glyceryl ether by rat cardiac myocytes, and of fatty acid, intact triglyceride and the glyceryl ether by perfused rat hearts. Cardiac myocytes efficiently extracted, oxidized and esterified oleic acid, but demonstrated little ability to utilize free glycerol. Although the glyceryl ether was efficiently extracted by myocytes, it was neither hydrolyzed or esterified. The perfused heart also extracted and metabolized unesterified fatty acid, and the fatty acid released during lipolysis of circulating lipoprotein triglyceride. The glyceride glycerol, however, was largely recovered (90%) in the perfusate suggesting inefficient myocardial utilization of either free glycerol or partial glycerides. Myocardial extraction of glyceryl monoether was demonstrated, but the monoglyceride analogue was also unmetabolized by intact heart tissue. The results suggest that if monoglycerides are produced by the action of lipoprotein lipase on circulating triglycerides, reutilization of intact monoglycerides for higher glyceride synthesis is not a major fate of these products.
Effect of specific dietary fatty acids on lipogenesis in the livers and mammary glands of lactating mice
Authors: Abraham S. , Hillyard L. A. , Lin C. Y. , Schwartz R. S.
Published: December 2006

The effects of linoleic, linolenic and columbinic acids fed as 4% of a high carbohydrate (50% glucose) diet on the activities and the amounts of several enzymes associated with fatty acid synthesis in livers and mammary glands of lactating mice were compared with those for stearic and oleic acids. Fatty acid synthesis, measured in vivo, was significantly lower in livers of mice ingesting all 3 polyunsaturated fatty acids (PUFA), whereas in mammary glands synthesis was lower only in mice receiving columbinic acid. The activities of fatty acid synthetase (FAS) and acetyl CoA carboxylase were significantly reduced in liver by all 3 PUFA, as were activities of glucose‐6‐phosphate dehydrogenase, malic enzyme (ME) and citrate cleavage enzyme (CCE), also associated with lipogenesis. In mammary gland, on the other hand, the activities of these enzymes were unaffected by dietary PUFA. The tissue contents of FAS, ME and CCE, measured by rocket immunoelectrophoresis, were found to be significantly reduced in liver by linoleate, linolenate and columbinate but were not significantly altered in mammary gland. The decrease in hepatic lipogenesis observed was principally due to a decrease in the amounts of these enzymes induced by the dietary PUFA but the inhibition in mammary gland caused by columbinate could not be accounted for by a reduction in enzyme contents and therefore may be due to allosteric effects which occur when fatty acid synthesis is measured with3H2O. The fatty acid composition in liver and mammary gland of dams and in liver and kidney of pups completely reflected dietary fatty acids. Columbinate made up ca. 20% of the total fatty acids in both tissues of the columbinic acid‐fed mice and ca. 15% in the pup tissues. This suggests that columbinate is incorporated into milk lipids of dams and is easily absorbed by pups. The elevated ratios of 16/16∶1 and 18/18∶1 in liver and mammary gland of dams and liver and kidney of the pups from dams fed linoleate, linolenate and columbinate suggest that each of these polyunsaturated fatty acids in the diet can inhibit the activity of Δ9 desaturase.
Use of antioxidants in the analysis of vatamins A and E in mammalian plasma by high performance liquid chromatography
Authors: Chow Faye I. , Omeye Stanley T.
Published: December 2006

A simple, sensitive, quantitative method for the simultaneous assay of retinol, α‐tocopherol and γ‐tocopherol in rat, guinea pig, monkey and human plasma was developed by using high performance liquid chromatography. It was found that antioxidant was required to stabilize the fat‐soluble vitamins in the plasma of rats. The effect of several antioxidants on the recovery of fat‐soluble vitamins was evaluated. Results showed that 0.125% butylated hydroxytoluene (BHT) in ethanol and 0.025% BHT in heptane yielded recoveries >95% in 0.1 ml plasma.
Immobilized lipoxygenase in continuous production of fatty acid hydroperoxides
Authors: Laakso Simo
Published: December 2006

Soybean lipoxygenase‐1 was covalently coupled to agarose with 75% recovery of catalytic activity. Because evidence was obtained that the immobilization resulted in improved operational stability of the enzyme, a lipoxygenase‐reactor and a continuous process for the synthesis of 13‐hydroperoxy‐linoleic acid and 15‐hydroperoxyarachidonic acid were developed. A procedure based on spectrophotometric hydroperoxide assay and constant oxygraphic monitoring of the effluent is presented for the calibration of the reactor to operate at the highest conversion efficiency when oxygenating quantitatively the substrate. Under these conditions, the reactor was capable of producing about 0.6 mg of hydroperoxy fatty acid/1.0 ml of wet gel/hr. The covalently coupled enzyme has been stable during six months of storage at 3 C in 0.2 M Na‐borate buffer, pH 9.0, and during the same period, its operational stability in the column has been unaltered under the conditions used.
Autoxidation of cholesterol fatty acid esters in solid state and aqueous dispersion
Authors: Korahani V. , Bascoul J. , Crastes de Paulet A.
Published: December 2006

Cholesteryl stearate, oleate, linoleate, linolenate and arachidonate were oxidized in solid form (at 100 C) and in a water dispersion (in the presence of potassium stearate, pH 7.5, 80 C). The unsaponifiable fraction was analyzed by capillary gas liquid chromatography. In the solid state, the oxidation rates of esterified cholesterol were high for stearate and oleate, low for the polyunsaturated esters and very low for free cholesterol. In water dispersion, the rates were reversed, e.g., free cholesterol oxidized more quickly than its stearic and oleic acid esters. The fatty chains in 18∶0 and 18∶1 inhibited the autoxidation of cholesterol. Hydroxylation of the cholesterol side chain only occurred during solid‐state autoxidation as previously observed by others. The 20‐ and 25‐hydroxycholesterols were never detected in the products of micellar reactions, regardless of which surfactant was used for micelle formation.
Cholesterol metabolism in human monocyte‐derived macrophages: Stimulation of cholesteryl ester formation and cholesterol excretion by serum lipoproteins
Authors: Albert Daniel H. , Traber Maret G. , Kayden Herbert J.
Published: December 2006

The role of lipoproteins and serum in the formation and accumulation of cholesteryl esters in human monocyte‐derived macrophages (HMD macrophages) was investigated; studies were also carried out with IC21 cells (a cell line derived from mouse peritoneal macrophages). Following preincubation of HMD macrophages with lipoprotein‐depleted serum (LPDS), both native and acetylated low density lipoprotein (LDL and AcLDL, respectively) stimulated the formation of cholesteryl esters with a resultant increase in cellular cholesteryl ester content. Cholesteryl ester formation and accumulation was also stimulated in macrophages exposed continuously to 25‐hydroxycholesterol. However, the stimulation of cholesterol esterification by either lipoproteins or 25‐hydroxycholesterol was not inhibited by progesterone in HMD macrophages, but was in the IC21 cells. Cholesterol efflux and the hydrolysis of cellular cholesterol ester, promoted by serum components, were studied in HMD macrophages preloaded with cholesteryl ester by incubation with 25‐hydroxy cholesterol. Replacement of the medium with one devoid of 25‐hydroxycholesterol resulted within 24 hr in at least a 30% decrease in the cholesteryl ester content of the HMD macrophages; replacement with a medium high in cholesterol acceptor content (LPDS or high density lipoprotein) and incubation for three days led to the most marked decreases in cellular cholesterol content. Thus, hydrolysis of the cholesteryl esters by HMD macrophages was not dependent on the presence of cholesterol acceptors in the medium, but cellular cholesterol content was.
Inhibition of lymphocyte capping by fatty acids in mouse and man
Authors: Santiago‐Delpín Eduardo A. , Román‐Franco Angel A. , Colón Julio I.
Published: December 2006

Lipid‐enriched diets have been related to a high cancer incidence in experimental animals for many years, and more recently, to assorted defects on the immune response. We investigated the effect of incubating human or murine (C3H/HEJ) lymphocytes with saturated (16∶0) and unsaturated (18∶1, 18∶2, 18∶3, 20∶4) fatty acids (12 μg for each 107 cells), on the ability to cap with andhuman or anti‐mouse anti‐IgM, μ‐chain specific antibody. Capping was also tested in obese (ob/ob, C57BL/6J) mice. Capping at 30 and 60 min was reduced by fatty acid incubation to 10–30% of control values in humans (p<.001), and to 30% of control values in mice (p<.01), regardless of degree of unsaturation. ob/ob capped normally. A lymphocyte membrane effect caused by fatty acids is observed in these experiments. Whether this is related to the dysimmunity caused by lipid diets cannot be assessed from our data, especially since all fatty acids, regardless of unsaturation, reduced the capping phenomenon.
A study of the plasma lipoproteins and the tissue lipids of the migrating lamprey,Mordacia mordax
Authors: Fellows Florence C. I. , McLean Robyn M.
Published: December 2006

Sea lampreys,Mordacia mordax, were collected in spring from the Yarra River, Victoria, during their upstream spawning migration, to study the lipid composition in their tissues and plasma and their lipid transport system. Plasma lipoproteins were isolated by preparative ultracentrifugation and their chemical compositions were analyzed. The major classes of lipoproteins were found to be similar to those of man and higher animals. Lipids from the muscle and liver were analyzed for fatty acids. The striking feature of the lipids in the migrating lamprey is the presence of very high levels of cholesterol in both plasma and muscle. The possible metabolic roles of cholesterol have been discussed.
Synthesis of diene prostaglandins in freshwater fish
Authors: Bandyopadhyay Gautam K. , Dutta Jyotirmoy , Ghosh Sudhamoy
Published: December 2006

Biosynthesis of PGD2, PGE2 and PGF2α in four species of freshwter fish,Tilapia mossambica, Cyprinus carpio, Heteropneustes fossilis andClarius batrichus was studied. Both arachidonic acid and PGH2 were used as substrates. When PGH2 replaced arachidonic acid in the enzymic reaction, there was a 3‐ to 4‐fold increase in PGE2 synthesis, but no such increase in the synthesis of PGF2α and PGD2 was observed.
The distribution of cholesterol and phospholipid composition in submitochondrial membranes from bovine adrenal cortex: Fundamental studies of steroidogenic mitochondria
Authors: Cheng Behling , Kimura Tokuji
Published: December 2006

The cholesterol contents and phospholipid compositions of mitochondria, microsomes and submitochondrial membranes from bovine adrenal cortex have been analyzed quantitatively. From our results, the following cholesterol contents were obtained: mitochondria, 6.2±0.9 mol %; microsomes, 18.4±2.8 mol %; mitochondrial inner membrane, 2.8±0.6 mol %; and mitochondrial outer membrane, 8.3±1.3 mol %. In addition, the phospholipid compositions of the mitochondrial inner and outer membranes were determined for the first time. Cardiolipin was found to be enriched in the inner membrane, whereas phosphatidylinositol was richer in the outer membrane. The general features of phospholipid compositions in the submitochondrial membranes resembled that of rat liver mitochondria.
Occurrence of wax esters in the tissues of the organge roughy (Hoplostethus atlanticus)
Authors: Grigor Murray R. , Thomas Colin R. , Jones Paul D. , Buisson David H.
Published: December 2006

The skin, skeleton and a fat‐filled swim bladder of the orange roughy (Hoplostethus atlanticus) each contained greater than 20% lipid by wet weight which was almost entirely wax esters. These had carbon numbers of 34–40 consistent with the major fatty acid being 18∶1 and the major fatty alcohols being 16∶0, 18∶1, 20∶1 and 22∶1. In contrast, the liver and the roe contained appreciable quantities of glycerolipids with 18∶1 and 22∶6 as the major fatty acids.
Variation of cyclopropenoid fatty acids in cottonseed lipids
Authors: Fisher Gordon S. , Cherry John P.
Published: December 2006

The proportions of the cyclopropenoid fatty acids (CPA) esters, malvalate and sterculate, varied little in lipids from individual cottonseeds. Coefficients of variation were 10% and 20% for seeds from a lock and 13 varieities, respectively. Within the seed, variations in CPA concentrations were very large. Cyclopropenoid fatty acid concentration in the lipids decreased from 28% in the root tip to 2% in the top of the axis, and to 0.02% in the portion of the cotyledons nearest to the hull. The axial portion was only ca. 5% of the kernel, yet it contained 75% of the CPA. Distribution of dihydrosterculic acid, the precursor of CPA, was similar to that of CPA. High concentrations of CPA were found in immature seeds, root tip and radicle of germinated seeds, and root tips of cotton plants.
Studies on the half‐life and the distribution of stearoyl‐CoA desaturase in the housefly
Authors: Wang Danny L. , Reitz Ronald C.
Published: December 2006

The half‐life of the stearoyl‐CoA desaturase was determined by using houseflies injected with puromycin. The LD50 for puromycin was determined to be 1.55 μ g/mg body wt for both sexes. By following the decay in specific activity of the desaturase after puromycin injection, the half‐life of this enzyme in 4‐day‐old females was calculated to be 9.35 hr, while in 1‐day‐old females it was 3.38 hr. The inhibition curve for the 3‐day‐old males never reached 100%, and a biphasic curve was observed. The early phase resulted in a half‐life of the desaturase of 2.41 hr, while the latter phase had a half‐life of 8.45 hr. In general, it appeared that the half‐life of the desaturase increased with age in either sex. Studies on the distribution of desaturase activity within the housefly showed that most of the activity was present in the integument; however, in the female, the onset of ovarian development seemed to shift the distribution of desaturase from the integument, towards the internal tissues. In the male, there appeared to be equal amounts of desaturase in integument and the fat body plus internal tissues at day 2, but by day 5 most of the activity was associated with the integument. The high specific activity and high percentage of total desaturase activity associated with integument coupled with the shift of distribution of desaturase in females during the onset of ovarian development may be indicative of a close correlation of the desaturase with alkene synthesis and possibly sex pheromone production.
Evaluation of the rapid micromethod for ultracentrifugal separation of labeled plasma lipoproteins
Authors: Shireman Rachel B. , Williams Debbie
Published: December 2006

The fractionations of plasma lipoproteins by 2 methods were compared to evaluate the rapid separation (Airfuge®) method for lipoprotein distribution studies. When [125I] labeled very low density, low density, and high density lipoproteins (VLDL, LDL, HDL), were separately centrifuged in buffers at d=1.006, 1.06 or 1.2 g/ml by the conventional ultracentrifuge and the Airfuge®, separations of the fractions in the Airfuge® were incomplete at both 5 C and 24 C, especially at d=1.006. [3H] Benzo (a)pyrene, when added to plasma, associates with the plasma proteins and lipoproteins, especially LDL. Compared to the standard techniques, the Airfuge® method greatly overestimated its distribution into VLDL. The distribution of [3H] vitamin D3 into the VLDL plus LDL fraction was also overestimated by the Airfuge® procedure. It is concluded that caution should be observed in quantitative studies of lipoproteins in the Airfuge®. A careful comparison of the distribution into or fractionation of lipoproteins by the 2 methods should always precede any quantitative determinations involving the Airfuge®.
Evidence that chlorpromazine inhibits sterologenesis at post‐HMGCoA reductase sites in rat liver, in vitro
Authors: Bell Frank P. , Hubert E. V.
Published: December 2006

The mechanism by which chlorpromazine inhibits cholesterogenesis in rat liver was investigated in vitro with the use of [14C] acetate and [14C] mevalonate as sterol precursors. Evidence was obtained that chlopromazine blocks cholesterogenesis at multiple sites beyond HMGCoA reductase (β‐hydroxy‐β‐methylglutarylCoA reductase, EC 1.1.1.34), the rate‐limiting step. Squalene synthesis from both labeled acetate and mevalonate is reduced to a similar extent in the presence of chlorpromazine (29–36% at 0.5 mM). The data indicate that there is also an impairment of conversion of squalene to lanosterol, and of lanosterol to cholesterol. Overall inhibition of cholesterogenesis by chlorpromazine reached 65–75% at 0.5 mM and was concentration‐dependent over the range 0.15–1.0 mM.
Biosynthesis of long‐chain polyenoic acids from arachidonic acid in cultures of enriched spermatocytes and spermatids from mouse testis
Authors: Grogan W. McLean , Huth Ellen G.
Published: December 2006

Primary spermatocytes (PS), round spermatids (RS) and condensing spermatids (CS) from mouse testes were enriched on Sta‐Put 1×g density gradients and cultured for 22 or 44 hr in the presence of [1‐14C]arachidonate. Mass and radioactivity were measured by gas radiochromatography of constituent fatty acids of the various complex lipid classes fractionated by thin layer chromatography. Patterns and levels of incorporation were compared with those of whole testis, both in vitro and in vivo. The 20∶4, 22∶4, 22∶5, 24∶4 and 24∶5 of the germinal cells contained levels of radioactivity in each lipid class which were consistent with an important role for the germinal cells in long‐chain polyenoic acid (LCPA) metabolism. Cells which represented later stages of spermatogenesis (RS, CS) incorporated much higher percentages and absolute amounts of radioactivity into the fatty acids derived from 20∶4 by elongation‐desaturation pathways than did PS or whole testis in vitro. These differences were most pronounced in triacylglycerol of CS. Distributions of mass and radioactivity among lipid classes suggest synthesis of triacylglycerol by CS with a high degree of specificity for 22 or 24 carbon LCPA at thesn‐3 position.
Increases in hyperlipoproteinemia, disturbances in cholesterol metabolism and atherosclerosis induced by dietary restriction in rabbits fed a cholesterol‐rich diet
Authors: Lacombe Christiane , Corraze Genevieve , Nibbelink Maryse
Published: December 2006

The influence of dietary restriction on cholesterol transport and metabolism was investigated in rabbits given standard or cholesterol‐rich diets (0.2 g cholesterol/kg body weight daily) eitherad libitum or with 50% caloric ration. Dietary restriction which has only a slight influence in control rabbits markedly aggravated the disturbances induced by exogenous cholesterol. With limited feeding, control rabbits presented a moderate increase in plasma cholesterol, whereas marked aggravation of hypercholesterolemia was observed in cholesterol‐fed rabbits. Analysis of the lipoprotein profile showed that the excess of plasma cholesterol with the restricted cholesterol‐rich diet corresponded to an increase in the concentration of very low density lipoprotein (VLDL) and low density lipoproteins (LDL) without any additional changes in the composition of these lipoproteins. No significant change appeared in the high density lipoprotein (HDL) concentration. The parameters of cholesterol metabolism were determined, from the curves of [3H] cholesterol radioactivity decrease, using a two‐pool model. The increase in cholesterol turnover rate induced by the cholesterol‐rich diet was accentuated by dietary restriction, whereas rabbits on standard restricted diet showed a slight decrease. The large increase in the size of both pools A and B in cholesterol‐fed rabbits was even more pronounced with limited feeding. Dietary restriction induced additional accumulation of cholesterol in the aortic wall and the grade of the lesions was also aggravated.
Stereospecificity of different lipases
Authors: Akesson B. , Gronowitz S. , Herslöf B. , Michelsen P. , Olivecrona T.
Published: December 2006

The stereospecificity of 4 lipases towards enantiomeric alkyldiacylglycerols and alkylmonoacylglycerols was investigated. No stereospecific breakdown of the former substrate was observed for lipases from pancreas,Rhizopus arrhizus, Pseudomonas fluorescens, or bile salt‐stimulated lipase from human milk. All lipases degraded 2‐oleoyl‐3‐tetradecyl‐sn‐glycerol faster than 1‐tetradecyl‐2‐oleoyl‐sn‐glycerol. Among X‐1‐acyl‐3‐alkylglycerol isomers, 1‐acyl‐3‐alkyl‐sn‐glycerol was preferentially attacked by the 3 first mentioned lipases. Possible mechanisms and metabolic implications for these stereospecificities are discussed.
Bromine levels in tissue lipids of rats fed brominated fatty acids
Authors: Jones Barbara A. , Tinsley Ian J. , Lowry Robert R.
Published: December 2006

Rats have been fed diets containing either 0.8% brominated corn oil or 0.5% of the ethyl ester of 9,10‐dibromostearate or 9,10,12,13‐tetrabromostearate. The brominated compounds were incorporated into semisynthetic diets and animals were observed after feeding periods of 5 days to 3 months. With the exception of adipose tissues, the highest concentration of lipid‐bound bromine was observed after 5 days on the experimental diets. It was also observed that feeding of the dibromostearate resulted in the highest levels of lipid‐bound bromine in heart, whereas the tetrabromostearate tended to result in higher levels of lipid‐bound bromine in liver. Brominated corn oil produced more substantial changes than the brominated fatty acid esters, inducing fatty livers and enlarged yellow hearts. Microscopic examination indicated myocardial degeneration and occasional early necrosis.
Toxicology of brominated fatty acids: Metabolite concentration and heart and liver changes
Authors: Jones Barbara A. , Tinsley Ian J. , Wilson Glenn , Lowry Robert R.
Published: December 2006

Rats were fed for 35 days diets containing 2% of either brominated corn oil (BCO), monoglyceride of dibromostearate (DBS), monoglyceride of tetrabromostearate (TBS) or a mixture of the two monoglycerides (BMG) which provided proportions of brominated acids comparable to that of the BCO. Hearts from all animals fed BCO were yellow colored and firm in texture. Myocardial cellular degeneration, mild to moderate edema and occasional small necrotic foci were observed. Hearts from animals fed DBS showed moderate edema and some slight necrosis. All diets produced an increase in lipid content of heart. Animals fed the experimental diets developed enlarged livers and showed elevated liver lipid content. The tetrabromostearate appeared to be the more active in producing these changes, in particular a severe intracellular fatty degeneration. Shorter‐chain (C‐16, C‐14) metabolites of di‐ and tetrabromostearate were identified and the concentration of brominated fatty acids in heart, liver and adipose tissue determined and found to account for 80% of the bromine detected in these tissues by neutron activation analysis. TBS accumulated in liver while the highest concentration of DBS was observed in heart lipids. Although the concentrations of brominated acids in heart and liver lipids were comparable in rats fed BCO or BMG, BCO produced the more pronounced effects. This differential could be due to additional active components in BCO or to a variation in response associated with changes in the location of the fatty acid on the glycerol molecule.
Altered microsomal phospholipid composition in the streptozotocin diabetic rat
Authors: Faas Fred H. , Carter William J.
Published: December 2006

Streptozotocin diabetes in the rat alters liver microsomal membrane fatty acid composition. The present study was undertaken to determine if such changes in fatty acid composition were due to changes in the amount of individual phosphoglycerides or to disproportionate changes in fatty acid composition in any of the individual phosphoglycerides. The diabetic animals showed a small increase in total microsomal phospholipid, which is due to a selective increase in the phosphatidylethanolamine fraction. The changes in fatty acid composition in the total lipid extract (decreased palmitoleic, oleic and arachidonic acids and increased linoleic and docosahexaenoic acids) from the diabetic animals were present in both the major phosphoglycerides, phosphatidylcholine and phosphatidylethanolamine, with very little change in fatty acid composition in the phosphatidylserine and inositol fraction. Further studies are necessary to delineate the cause of the abnormal membrane phospholipid composition in the diabetic animal.
Effect of ingestion of thermally oxidized frying oil on peroxidative criteria in rats
Authors: Izaki Yaeko , Yoshikawa Shunichi , Uchiyama Mitsuru
Published: December 2006

Thermally oxidized rapeseed oils (4 levels of deterioration; used by a manufacturer of fried fish paste in a conventional manner) were fed to rats at a practical level of concentration. Rats were fed a diet ad libitum for 13 weeks that contained 15% of a test oil. The effects of the diet on several biochemical criteria related to peroxidative alterations were investigated.

In groups given thermally oxidized oils relative liver weight, relative kidney weight, thiobarbituric acid‐reactive substances (TBA‐RS) in the liver and reduced glutathione content were increased significantly in proportion to the degree of deterioration of the oil, compared with the group given fresh oil. Tocopherol contents in both serum and liver were decreased considerably in proportion to the deterioration level of the supplied oils.

The above criteria correlated well with various deterioration indices of the oil. For instance, TBA‐RS was well correlated (p<0.001) with petroleum ether‐insoluble oxidized fatty acid (r=0.9191), column chromatographically separated polar fraction (r=0.9056), glyceride dimer fraction (r=0.9023) and carbonyl value (r=0.8647).
Fatty acid metabolism in young oysters,Crassostrea gigas: Polyunsaturated fatty acids
Authors: Waldock M. J. , Holland D. L.
Published: December 2006

Tetraselmis suecica andDunaliella tertiolecta were grown for 24 hr in the presence of14C sodium bicarbonate and then fed separately to batches of juvenile oysters,Crassostrea gigas, for 3 days.D. tertiolecta contained fatty acids no longer than C18; 22∶6ω3 was absent inT. suecica. Analysis of the oyster fatty acids by radio gas chromatography (GC) showed that oysters were able to incorporate some of the dietary14C label into long‐chain fatty acids not supplied in the diet, e.g., C20 and C22 mono‐ and polyunsaturated fatty acids, and particularly 20∶5ω3. However, the low14C incorporation into fatty acids longer or more unsaturated than those supplied in the diet suggests that elongation and desaturation activity in young oysters is not sufficient to sustain optimum growth.
Metabolism of arachidonate in rat testis: Characterization of 26–30 carbon polyenoic acids
Authors: Grogan W. McLean
Published: December 2006

Fatty acid methyl esters of long‐chain polyenoic fatty acids (LCPA) from rat testis injected with [1‐14C] arachidonate were analyzed and separated by reversed‐phase high performance liquid chromatography (RP‐HPLC). Earlier, all previously identified LCPA were prepared in high purity along with 4 previously unidentified fatty acids, which were further characterized by capillary gas chromatography (GC), catalytic hydrogenation and alkaline isomerization. Unidentified fatty acids proved to be 26∶4, 26∶5, 28∶5 and 30∶5. All of these LCPA incorporated14C from arachidonate (20∶4) to specific activities that were comparable to that of 20∶4 and previously identified metabolites of 20∶4 and much greater than specific activities of 18∶1n−9 or 22∶6n−3. LCPA were analyzed on a capillary GC system capable of resolving knowncis‐trans and positional isomers of the n−3, n−6, n−7 and n−9 families of unsaturated fatty acids. Log plots of isothermal retention times and normal plots of temperature programmed retention times were linear (r=0.999) in carbon number when values for known and previously unidentified LCPA of 4 or 5 double bonds, respectively, were coplotted. Thus, the newly identified fatty acids belong to the n−6 family of fatty acids synthesized from arachidonic acid.
HPLC of plasmalogen‐containing phosphatidylcholine under reverse‐phase or argentation conditions
Authors: Marmer William N. , Foglia Thomas A. , Vail Peter D.
Published: December 2006

Two approaches to the high pressure liquid chromatography (HPLC) isolation of intact plasmalogens were investigated. The first used reversed‐phase HPLC and sought to take advantage of subtle differences in the hydrophobicity of the alk‐1‐enyl chain from the acyl counterpart. On a C‐18 column, bovine heart phosphatidylcholine (PC), which was 47% plasmalogen, was separated into a number of fractions that differed in their molecular species composition. One combination of fractions amounted to a 26% yield of PC enriched to 82% plasmalogen. The second approach sought to take advantage of the uniquely electron‐rich functionality of the plasmalogens, the alk‐1‐enyl ether double bond, and its potential to coordinate with heavy metal ions. Specificially, bovine heart PC was applied to a cation‐exchange type HPLC column in the silver ion mode. Although complete exchange of all the active sites of the column with silver ion led to complete retention of PC, partial activation with silver ion resulted in the separation of the PC into fractions, according to the degree of unsaturation. Plasmalogen‐rich fractions eluted last and remained intact during the process. One combination of these fractions amounted to a 49% yield of PC enriched to 72% plasmalogen. Use of a cation‐exchange system in the mercuric ion mode led to on‐column hydrolysis of the plasmalogen; with palladium ion, the metallic species was stripped from the column by the eluting lipid.
Inhibition of human lecithin cholesterol acyltransferase by monoterpenes
Authors: Cooney Robert V. , Nemhauser Jefferey , Morin Robert J.
Published: December 2006

The lecithin‐cholesterol acyltransferase activity of human plasma was found to be inhibited by Rowachol, a proprietary mixture of pure monoterpenes. Menthol, the major ingredient in Rowachol (32%), and a number of other monoterpenes were found to inhibit the enzyme independently. Concentrations of monoterpenes required to achieve 50% inhibition were of the same order of magnitude as the cholesterol concentration present in the reaction mixture.
Tissue culture of cocoa bean (Theobroma cacao L.): changes in lipids during maturation of beans and growth of cells and calli in culture
Authors: Tsai C. H. , Kinsella J. E.
Published: December 2006

Callus cultures ofTheobroma cacao L., initiated from explants of immature cocoa bean cotyledons, contained 5.3%–6.4% lipids (dry wt basis). The major fatty acids were palmitic, oleic and linoleic acids. Cell suspensions contained 5.7–7.7% total lipids which had a higher polyunsaturated fatty acid content than total lipids of the calli. Phospholipids and glycolipids were the predominant lipid classes of calli and cell suspensions. Immature cocoa beans at early stages of development contained much higher polyunsaturated fatty acids, higher polar lipids and lower triglycerides than did mature ripe beans. Ripe cocoa beans contained 54% total lipids of which 96.8% where triglycerides. The fatty acid composition of total lipids of calli and cell suspensions were similar to those of the immature cocoa beans.
Essential fatty acids in trout serum lipoproteins, vitellogenin and egg lipids
Authors: Leger Claude , Fremont Lucie , Marion Didier , Nassour Ibrahim , Desfarges Marie‐Françoise
Published: December 2006

This paper describes evidence of (n−3) and particularly of 22∶6 (n−3) fatty acid enrichment in trout lipoproteins as well as in vitellogenin, egg lipovitellin and oil globule. Among the lipoproteins, HDL and LDL were the main forms of blood lipid transport, whereas phospholipids and cholesteryl esters are the preferential chemical carriers for (n−3) fatty acid transport. However, cholesteryl esters were less important as esterified fatty acid carriers than in man. Taken together with the data obtained in mammals, our results suggest that there may be a relationship between EFA activity and the distribution of the EFA among the lipoprotein lipid fractions in vertebrates, irrespective of the EFA series. Administration of an (n−3) fatty acid deficient diet for three months prior to trout spawning produced a significant increase in egg lipid content, primarily as a result of the increase of the oil globule composed almost exclusively of triacylglycerols. This diet decreased the 22∶6 (n−3), as well as the (n−3) fatty acid contents of lipoproteins, lipovitellin, vitellogenin and the oil globule. In contrast, the (n−3) fatty acid level was always higher in lipoproteins and lipovitellin than in the vitellogenin and the oil globule. Moreover, the relative levels of 22∶6 (n−3) and total (n−3) fatty acids were quite similar in lipoproteins and lipovitellin on the one hand, and in vitellogenin and the oil globule on the other. These findings suggest a direct relationship between the two forms of plasma lipid transport and the two egg compartments. During ovogenesis, dietary lipids seemed to be diverted from the adipose tissue and essentially deposited in the egg.
High performance reversed phase chromatography of cholesterol and cholesteryl esters of human plasma lipoproteins
Authors: Perkins Edward G. , Hendren David J. , Bauer John E. , El‐Hamdy Ali H.
Published: December 2006

Cholesterol and cholesteryl esters were separated according to their carbon number and number of double bonds by high performance reversed‐phase chromatography (HPRC) using acetonitrile/chloroform/methanol (1∶1∶1, v/v) as a mobile phase. It was found that within the same equivalent carbon number (ECN) category, cholesterol esters with the highest number of double bonds eluted ahead of those with a lower number of double bonds, and with thecis isomers eluting ahead of theirtrans partners. Thus, cholesteryl oleate (C27‐18∶1c) elutes ahead of cholesteryl palmitate (C27‐16∶0) and ahead of cholesteryl elaidate (C27‐18∶1t). Human lipoprotein, as well as rat liver cholesteryl esters, were separated using this technique.
Biosynthesis of fatty acids byTrypanosoma cruzi
Authors: Aeberhard Ernesto E. , de Lema Mirta G. , Bronia Delia I. H.
Published: December 2006

The incorporation of [1‐14C] acetate into fatty acids by cultured epimastigotes ofTrypanosoma cruzi was studied. After 8, 24, and 48 hr incubation with labeled precursor, up to 2.8% of the initial radioactivity added to the medium was found in theT. cruzi long chain fatty acids. Saturated (16∶0 and 18∶0), monounsaturated (18∶1ω9), and diunsaturated (18∶2ω6) fatty acids were synthesized. Both the pattern of incorporation of labeled acetate into the fatty acids and the decarboxylation ratios found suggest that de novo synthesis of fatty acids has taken place.
The lipids of kangaroo meat
Authors: Redgrave Trevor G. , Jeffery Faye
Published: December 2006

Lipids were extracted from lean meat of kangaroos, sheep and beef cattle. Kangaroo meat lipids contained more phospholipid and less triacylglycerol than sheep meat or beef, and had a higher proportion of polyunsaturated linoleic and arachidonic acids. These results were obtained with kangaroos from the more arid inland region of Australia, and were similar to results obtained previously with kangaroos from a milder climatic region with a higher rainfall. Hence, the composition of the meat lipids is unaffected by the increased aridity of inland zones. The findings are of nutritional significance because kangaroo meat is now commercially available for human consumption.
Hypolipidemic effects of gossypol in cynomolgus monkeys (Macaca fascicularis)
Authors: Shandilya L. N. , Clarkson T. B.
Published: December 2006

The effect of gossypol acetic acid (gossypol) on plasma lipid concentrations was studied in adult male cynomolgus monkeys consuming a diet containing 0.19 mg cholesterol/Kcal. Gossypol was administered orally at 5 (n=4) or 10 (n=3) mg/kg/day for 6 months. A significant decrease in total plasma cholesterol (TPC) and low density lipoprotein and very low density lipoprotein‐cholesterol (LDL + VLDL‐chol) concentrations was observed without any significant decrease in plasma high density lipoprotein‐cholesterol (HDL‐chol) levels among 10 mg/kg/day gossypol‐treated animals. This is a new therapeutic property of gossypol that has not been previously reported. No appreciable differences were observed in plasma levels of TPC and LDL + VLDL‐chol among 5 mg/kg/day gossypoltreated amimals when compared to controls until the gossypol dosage was increased to 10 mg/kg/day, thus suggesting that hypolipidemic effect of gossypol is dose‐dependent. In general, no adverse clinicopathological findings were noted except a temporary diarrhea and loss of appetite among 10 mg/kg/day gossypol‐treated animals during the initial stages of treatment. In conclusion, it is tempting to speculate that gossypol might possibly reduce the intestinal absorption of dietary cholesterol or it may reduce the hepatic synthesis of low density lipoproteins. These results also suggest that gossypol may be a particularly useful drug in lowering plasma cholesterol concentrations in addition to its previously demonstrated antifertility properties in males.
Effects of dietary 9‐trans, 12‐trans linoleate on arachidonic acid metabolism in rat platelets
Authors: Hwang D. H. , Chanmugam P. , Anding R.
Published: December 2006

In order to determine the minimal amount of dietary 9‐trans,12‐trans‐linoleate which can decrease endoperoxide metabolites synthesized and their precursor in rat platelets, graded amounts (0, 0.1, 0.5, 1.0, 2.5%) of thetrans‐linoleate were fed to rats with a constant amount of all‐cis‐linoleate (2.5%) for 12 weeks. Arachidonic acid levels in platelet phospholipids of groups receiving thetrans‐linoleate at 2.5 and 1.0% were significantly (p<0.01) lower than that of the control receiving notrans‐linoleate. Concentrations of TXB2 and PGF2α in sera of the group receiving 2.5%trans‐linoleate were significantly (p<0.05) lower than those of the control; however, there was no difference between the group receiving 1.0%trans‐linoleate and the control. To determine whether the difference in serum concentrations of endoperoxide metabolites could be manifested if rats were fed for longer period of time, 2 groups of rats were again fed diets containing 0 and 1.0%trans‐linoleate, respectively, for 16 weeks. Arachidonic acid in platelet phospholipids of the group receiving thetrans‐linoleate was again significantly (p<0.01) lower than that of the control group. Concentrations of TXB2 and PGF2α, and 12‐hydroxyeicosatetraenoic acid formed in platelets, were smaller in the group receivingtrans‐linoleate than the control group; however, the difference was not statistically significant. These results indicated that all‐trans‐linoleate can reduce arachidonic acid metabolites formed in rat platelets when its dietary level is equal to or exceeds the level of all‐cis‐linoeate.
Preparation ofcis,cis,cis‐5,8,11‐eicosatrienoic acid from arachidonic acid
Authors: Ghosh Amitabha , Koley Malati , Dutta J.
Published: December 2006

Arachidonic acid was reduced by hydrazine to yield isomeric eicosatrienoic acids with other products. Methylcis,cis,cis‐5,8,11‐eicosatrienoate was isolated from the products by silver ion chromatography and preparative gas liquid chromatography in 8% yield. The structure was confirmed by spectral studies and oxidative degradation.
The lipid composition of human liver microsomes
Authors: Waskell Lucy , Koblin Donald , Canova‐Davis Eleanor
Published: December 2006

The lipid composition of human liver microsomes isolated from liver biopsy samples obtained at abdominal surgery has been determined. Human liver microsomal phospholipid is composed of 49% phosphatidylcholine, 31% phosphatidylethanolamine, 14% phosphatidylserine+phosphatidylinositol and 6% sphingomyelin, very similar to the phospholipid composition of rat liver microsomes. The fatty acid composition of human liver microsomes is remarkable only for its content of polyunsaturated fatty acids, with 20% of the fatty acids consisting of arachidonic, docosatetraenoic, docosapentaenoic and docosahexaenoic acids. This value contrasts with 33% in rats and 9% in rabbits. The molar cholesterol/phospholipid ratio in human liver microsomes is 0.069, similar to the ratio in rat and rabbit microsomes.