bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of myocardial necrosis in male albino rats by manipulation of dietary fatty acid levels
Authors: Kramer J. K. G. , Farnworth E. R. , Thompson B. K. , Corner A. H. , Trenholm H. L.
Published: December 2006

A comprehensive statistical analysis had shown a significant correlation between the incidence of myocardial lesions in male albino rats and the concentration of certain dietary fatty acids. To test this result under controlled conditions, male rats were fed for 16 weeks diets containing 20% by weight soybean oil or a low erucic acid rapeseed (LEAR) oil. Both dietary oils contained substantial amounts of linolenic acid, and both groups developed a high incidence of myocardial necrosis. The addition of dietary saturated fatty acids to the oil in the form of cocoa butter significantly lowered the incidence of heart lesions in both groups. The addition of cocoa butter resulted in increased absorption of saturates and increased growth. Replacement of the cocoa butter by at least an equal amount of synthetic triolein resulted in no significant changes in the cardiopathogenic response compared to the original oils, thus ensuring that the reduction in heart lesions associated with the addition of cocoa butter was not due to dilution of cardiopathogenic compounds in the original vegetable oils. These results support the hypothesis that myocardial lesions in male rats are related to the balance of dietary fatty acids and not to cardiotoxic contaminants in the oils. Changes in the dietary fatty acids did not appear to influence the proportion of the cardiac phospholipids, but their fatty acid composition was markedly influenced. Dietary linolenic acid affected the C22 polyunsaturated fatty acids (PUFA) and dietary saturates increased the level of saturates in cardiac phospholipids. The level of arachidonic acid and total C22 PUFA did not appear to be affected by diet.
Hepta‐and nonadecene from marine fish
Authors: Hoshita Nobuhiko , Kodama Youtaro
Published: December 2006

Two monoalkenes were detected in gizzard shad (Clupanodon punctatus) and sardine (Sardinops melanosticta) by gas chromatography and were identified by combined gas chromatography‐mass spectrometry of their cyclic boronate and dioxolane derivatives ascis‐6‐n‐heptadecene andcis‐8‐n‐nonadecene.
Effect of diethyl maleate and glutathione on linoleate peroxidation
Authors: Fernandez Nancy , Valenzuela Alfonso , Fernandez Virginia , Videla Luis A.
Published: December 2006

The antioxidant effect of diethyl maleate and reduced glutathione was studied in an in vitro peroxidizing system. Linoleate peroxidation, measured as conjugated diene formation, was not altered by diethyl maleate (2 or 4 mM), whereas the addition of reduced glutathione (1, 2 or 4 mM) elicited a marked and progressive reduction. This effect of glutathione is not modified by diethyl maleate. The inhibition of linoleate peroxidation by glutathione was found concomitantly with a decrease in the concentration of its reduced form and a corresponding increase in glutathione disulfide levels, so that the total equivalents of reduced glutathione in the system remained constant. It is concluded that diethyl maleate does not have antioxidant properties in a peroxidizing system, as found for reduced glutathione.
Effects of phosphatidylcholines on de novo synthesis and excretion of sterol by L‐929 fibroblasts
Authors: Thomaidis Georgios , Holmlund Chester E.
Published: December 2006

The effects on [14C] sterol synthesis and excretion by exposure of L‐929 cells to several phosphatidylcholines (PC) has been examined. No significant effects were noted on either parameter during a 6‐hr period if exposure of cells to the phospholipid preceded the addition of [1‐14C] acetate by just 30 min. However, if cultures were grown in media containing delipidized serum and 2×10−5 M PC through 2 or more subculturings prior to adding [1‐14C] acetate, the amount of [14C] sterol increased in both cells and medium by 70–200% when saturated or monounsaturated PC were used. Dilinoleylphosphatidylcholine (18∶2 PC) at the same concentration did not stimulate synthesis or excretion of newly synthesized sterol. Total cellular sterol was determined by gas chromatography, and was only marginally affected by long‐term exposure to dipalmitylphosphatidylcholine (16∶0 PC), whereas the total sterol of the medium increased by 4‐fold over a 19‐hr period. Cultures which had been exposed to 16∶0 PC through 3 subculturings continued to display enhanced de novo sterol synthesis, but not excretion, for up to 5 hr after replacement with fresh medium lacking 16∶0 PC. The disparity in response to 2×10−5 M levels of 16∶0 PC and 18∶2 PC may relate to differences in metabolism of cellular fatty acids, whereas relatively small changes in the cellular fatty acid composition were noted with 16∶0 PC‐treated cells. The results indicate that extracellular PC can promote sterol synthesis and excretion by L‐929 cells, and that the magnitude of this response is influenced by the time of exposure to the phospholipid and by its fatty acid composition.
Use of radiolabeled hexadecyl cholesteryl ether as a liposome marker
Authors: Pool G. L. , French M. E. , Edwards R. A. , Huang L. , Lumb R. H.
Published: December 2006

Radiolabeled hexadecyl cholesteryl ether can serve as an effective marker for liposomes in a variety of studies. This paper demonstrates the use of a cholesteryl ether marker in the assay of phospholipid transfer protein activity and in assessing phospholipid vesicle‐cell interactions. The cholesteryl ether has the advantages of ease of synthesis, metabolic inertness, lipid solubility and nonexchangeability.
An improved procedure for the synthesis of choline phospholipids via 2‐bromoethyl dichlorophosphate
Authors: Hansen William J. , Murari Ramaswamy , Wedmid Yuri , Baumann Wolfgang J.
Published: December 2006

Choline phospholipids can be conveniently synthesized by reaction of a lipophilic alcohol, such as diacylglycerol, with 2‐bromoethyl dichlorophosphate followed by nucleophilic displacement of the bromine with trimethylamine. We found that the low yields often encountered in the initial phosphorylation step are particularly due to exchange of both chlorines for alkoxy functions (triester formation) and to chlorination of the alcohol by 2‐bromoethyl dichlorophosphate. However, these drawbacks can be overcome by proper choice of the reaction medium and by optimizing other reaction conditions. The procedure described is efficient and most versatile, and it lends itself to the preparation of a wide range of choline phospholipids containing a glycerol, diol, or long‐chain alkyl backbone and bearing various aliphatic functions. Proton and carbon‐13 nuclear magnetic resonance spectroscopy proved useful in establishing the homogeneity and structures of the synthetic intermediates and byproducts and of the choline phospholipids synthesized.
Effect of garlic (Allium sativumlinn) on serum lipoproteins and lipoprotein cholesterol levels in albino rats rendered hypercholesteremic by feeding cholesterol
Authors: Kamanna V. S. , Chandrasekhara N.
Published: December 2006

The hypocholesteremic activity of garlic was tested by incorporating freeze‐dried garlic powder at 0.5, 1.0, 2.0 and 3.0% levels in an atherogenic diet fed to rats. It was observed that 0.5 and 1.0% levels were not effective whereas the other 2 levels were. The group fed 2.0% garlic powder had much lower serum cholesterol level than the one fed 3%. The increased levels of low density lipoproteins (LDL) and LDL‐cholesterol in rats fed the atherogenic diet were partly reversed in rats receiving a supplement of 2% garlic powder. On a cholesterol‐containing diet, high density lipoproteins (HDL) and HDL‐cholesterol levels were decreased. Inclusion of garlic powder in the atherogenic diet enhanced the percentage of HDL whereas no change was observed in HDL cholesterol levels. Commercial garlic pearls (equivalent to 0.15% garlic powder in the diet) produced a significant decrease in serum and liver cholesterol levels in rats fed the atherogenic diet. On the other hand, asafoetida at 1.5% level failed to reduce the serum cholesterol levels in the cholesterol‐fed rats.
A simple method for labeling lipids in the bile lipoprotein
Authors: Nalbone Gilles , Vigne Jean‐Louis , Lafont Huguette , Augeire‐Charbonnier Monique , Chabert Christiane , Lairon Denis , Hauton Jacques C.
Published: December 2006

A simple method is proposed for the specific radioactive labeling of phosphatidylcholines and cholesterol in the bile lipoprotein complex. It can be used for human and animal bile samples and results in labeling with the desired specific radioactivity and position. Experiments which determined the intermicellar concentration of lipid constituents suggested that incorporation of radioactive lipids could occur through small dialyzable structures termed mixed premicelles in therm odynamic equilibrium with the bile lipoprotein complex.
Metabolism of fatty acids in rat brain microsomal membranes
Authors: Aeberhard Ernesto E. , Gan‐Elepano Minerva , Mead James F.
Published: December 2006

Using a technique in which substrate fatty acids are incorporated into microsomal membranes followed by comparison of their rates of desaturation with those of exogenous added fatty acids, it has been found that the desaturation rate may be greater for the membrane‐bound substrate than for the added fatty acid. Moreover, the product of the membrane‐bound substrate is incorporated into membrane phospholipid whereas the product of the exogenous substrate is found in di‐ and triacyl glycerols and in free fatty acids, as well. These and other findings point to a normal sequence of reaction of membrane lipids with membrane‐bound substrate involving transfer of fatty acid from phospholipid to the coupled enzyme systems without facile equilibration with the free fatty acid pool.
Lysophosphatidylcholine acyltransferases activity during experimental cholelithiasis
Authors: Allen Rutledge F. , Hickman Donn M. , Dunn Joceyln J. , Frey Charles F. , Matson Robert S.
Published: December 2006

The accumulation of (1‐palmitoyl)lysophosphatidylcholine, lysolecithin, in gallbladder bile was observed during the first week of cholesterol‐induced experimentals cholelithiasis using the prairie dog model for cholesterol gallstone formation. Gallbladder fluid transport function decreased as bile lysolecithin concentration increased. These observations suggest that lysolecithin play an important, early role in the etiology of gallstone disease. Furthermore, the relative activities of hepatic and gallbladder mucosa lysophosphatidylcholine acyltransferase and acylcoenzyme A hydrolases may be responsible for the turnover of gallbladder bile lysolecithin.
Ceramide structure of sphingomyelin from human milk fat globule membrane
Authors: Bouhours Jean‐François , Bouhours Danièle
Published: December 2006

Sphingomyelin was purified from human milk fat globule membrane and submitted to phospholipase C to yield ceramide. The structure of this ceramide was investigated by gas liquid chromatographic analyses of its components, fatty acids and sphingoid bases. The structure of the native ceramide was confirmed by direct‐inlet mass spectrometry. It was shown to contain a major base C18‐sphingosine associated with a high proportion (60%) of C20, C22, C24 and C24∶1 nonhydroxylated fatty acids. As these very long‐chain fatty acids might be of nutritive importance, the concentration of sphingomyelin in human milk and its distribution in cream and skim milk were established.
Effects of clofibrate and tiadenol on the elimination of lipids and bile acids in rat bile
Authors: Cuchet P. , Morrier C. , Cand F. , Keriel C.
Published: December 2006

The aim of the work presented here was to compare the biliary elimination of cholesterol and the different bile acids of rats that had been made hypolipidemic by short‐term treatments with clofibrate or tiadenol. Both treatments induced a significant decrease in cholesterol output in the bile. The analysis of the different bile acids showed a decrease in dihydroxylated acids elimination (especially CDC acid) without any difference between the 2 sexes. This decrease was associated with an increase in cholic acid excretion. These results are directly correlated with the dose of the administered hypolipidemic drug. The drugs caused a significant increase in the ratio of trihydroxylated acids to dihydroxylated acids. The maximal effect on the concentration of the biliary acids of the bile and on the output was obtained, for both drugs, with a treatment of 200 mg/kg/day. Clofibrate had a greater effect than tiadenol at this dose. Both drugs show a greater effect on lowering serum lipid levels in female animals when compared to males, whereas elimination of bile cholesterol and modifications of bile acids were greater in male animals than female animals.
Fatty acid and cholesterol synthesis from specifically labeled leucine by isolated rat hepatocytes
Authors: Mathias Melvin M. , Sullivan Ann C. , Hamilton James G.
Published: December 2006

Hepatocytes isolated from female rats meal‐fed a high‐glucose diet were incubated in Krebs‐Henseleit bicarbonate medium containing 16.5 mM glucose,3H2O, and14C‐labeled amino acids (−)‐Hydroxycitrate depressed the incorporation of3H2O and [14C] alanine into fatty acids and cholesterol. Incorporation of [U‐14C] leucine into lipids was not affected but incorporation of3H2O into lipids was decreased significantly by (−)‐hydroxycitrate. (−)‐Hydroxycitrate depressed the incorporation of radioactivity from [2‐14C]leucine into fatty acids and cholesterol by 61 and 38%, respectively, and stimulated the incorporation of radioactivity from [4,5‐3H]leucine 35 and 28%. As [2‐14C]leucine labels the acetyl‐CoA pool and [4,5‐3H]leucine labels the acetoacetate pool, it was concluded that mitochondrial 3‐hydroxy‐3‐methylglutaryl‐CoA is not incorporated intact into cholesterol, and that acetoacetate can be activated effectively in the liver cytosol for support of cholesterol and fatty acid synthesis.
Metabolic discrimination between cholesterol and β‐amyrin byPhytophthora cactorum
Authors: Nes W. David , Saunders Gary A. , Heftmann Erich
Published: December 2006

When cultures ofPhytophthora cactorum were incubated on solid medium for 3 weeks in the dark at 20 C with [14C] cholesterol or [14C]β‐amyrin, the [14C] cholesterol was assimilated into the advancing mycelium to a greater extent than the [14C]β‐amyrin. Examination of the mycelium and medium for radioactive metabolites showed significant differences in the metabolism of the 2 labeled compounds. Cholesterol was converted mainly to esters and to some extent to glycosides, whereas β‐amyrin was only slightly converted to esters and not at all to glycosides.
Aqueous lipid phases of relevance to intestinal fat digestion and absorption
Authors: Lindström Mats , Ljusberg‐Wahren Helena , Larsson Kåre , Borgström Bengt
Published: December 2006

The phase behavior of monoglyceride/water systems, with oleic and linoleic acid as the dominating fatty acid residues, was investigated. Increased solubilization of triglycerides (oil) or oleic acid in the cubic liquid‐crystalline phase formed by monoglyceride and water resulted in the formation of a reversed hexagonal liquid‐crystalline phase followed by an L2‐phase. The liquid‐crystalline phases have different dispersion properties compared to each other in dilute micellar bile salt solutions. The cubic phase is found to be easily dispersed. The relevance of aqueous lipid phases other thah micellar is discussed in relation to intestinal lipid digestion and absorption.
A nondestructive spray reagent for the detection of prostaglandins and other lipids on thin layer chromatograms
Authors: Goswami S. K. , Kinsella J. E.
Published: December 2006

The spray reagent 8‐hydroxy‐1,3,6‐pyrenetrisulfonic acid trisodium salt (10 mg/100 ml methanol) is extremely sensitive for locating prostaglandins on thin layer chromatograms. This reagent does not alter the PG, nor interfere with liquid scintillation counting.
A 2‐phase liquid scintillation assay for glycolipid synthetases
Authors: Hospattankar Ashok V. , Radin Norman S.
Published: December 2006

Glycolipid synthetases can be assayed conveniently by incubating the lipid substrate with the radiosugar‐labeled nucleotide in a small plastic scintillation vial. At the end of the incubation period, water and perchloric acid are added, thenn‐butanol, then a toluene‐based scintillation cocktail. The radioactive lipid partitions into the scintillation fluid, leaving excess sugar nucleotide in the aqueous phase. Only a small fraction of the total radioactivity in the aqueous layer is detectable. This method is illustrated for ceramide: UDP‐glucose glucosyltransferase. The approach should be applicable to other lipid synthetases that can be assayed with a radioactive hydrophilic substrate.
On the occurrence of α‐tocopherolquinone in rat tissue
Authors: Bieri John G. , Tolliver Teresa J.
Published: December 2006

The amount of α‐tocopherolquinone in rat liver has been reinvestigated comparing (a) a conventional procedure including saponification and thin layer chromatography followed by high peformance liquid chromatography (HPLC), with (b) the direct HPLC analysis of a total lipid extract. Recovery of added α‐tocopherolquinone was quantitative with both procedures. In contrast to a recent report of 124 nmol/g in rat liver, we found no more than 1–4 nmol/g by procedure a and less than 1 nmol/g by procedure b.
Effect of eicosatetraynoic acid on liver and plasma lipids
Authors: Wood Randall
Published: December 2006

Groups of rats were fed a fat‐free diet supplemented with 0.5% safflower oil (control) or the control diet containing 0.5% of 5,8,11,14‐eicosatetraynoic acid (TYA). Blood was collected weekly and plasma lipids analyzed. After 4 weeks, the animals were killed and the liver lipids were analyzed in detail. The acetylenic fatty acid perturbed plasma neutral lipid and phospholipid class concentrations and reduced growth rates. Liver triglyceride concentrations were reduced dramatically in the TYA fed animals, suggesting interference with complex lipid synthesis. Plasma and liver triglycerides were shifted to higher molecular weight species suggesting that TYA affected fatty acid metabolism. The phospholipids showed an accumulation of 18∶2 and a fall in 20∶4 percentages indicating an inhibition in the conversion of linoleate to arachidonate. All major lipid classes exhibited an increase in 18∶1 levels. Analysis of the octadecenoate positional isomers indicated the proportion of oleate increased substantually in all lipid classes whereas vaccenate proportions had fallen dramatically. All of the data collectively suggest that TYA inhibits the elongation of unsaturated fatty acids. A group of rats bearing hepatoma 7288CTC were also fed the TYA diet. Host liver lipids were affected by TYA similar to normal TYA fed animals, but the effects on hepatoma lipids were marginal.
Effect of hepatoma on host liver, heart and lung lipids as tumor growth progresses
Authors: Wood Randall , Zoeller A. , Matocha M.
Published: December 2006

A large group of rats was transplanted with hepatoma 7288CTC and 4 animals were sacrificed at 3‐day intervals for four weeks. Lipid class concentrations, fatty acid class compositions, and the distribution ofcis octadecenoate positional isomers in the major lipid classes were determined for heart, liver and lung at each time period. The hearts of host animals decreased in dry weight as hepatoma growth progressed. At day 30, heart weights were less than two‐thirds of initial weights. Lipid class concentrations changed in all three tissues: cholesterol and free fatty acids increased in liver; triglycerides and cholesterol decreased and then increased in heart; and cholesterol, triglycerides and PC decreased in lung as tumor growth progressed. Hexadecenoate percentages exhibited a progressive decrease in all the lipid classes of heart and liver. Although total octadecenoate percentages showed only minor changes, oleate concentrations generally increased and vaccenate levels decreased in heart and liver lipids as tumor growth progressed. Palmitoleate, precursor of vaccenate, exhibited decreased concentrations early that resulted in decreased vaccenate levels. Decreased palmitoleate concentrations suggest inhibition of the Δ9 desaturase system, but normal oleate concentrations complicate this interpretation. Most of the changes in the lipids were detectable 3–6 days after transplantation, indicating the hepatoma affects the lipid metabolism of the host animal early and well in advance of nutritional stresses.
Photosensitized oxidation of methyl linolenate. Secondary products
Authors: Neff W. E. , Frankel E. N. , Weisleder D.
Published: December 2006

Previous studies of secondary oxidation products by high‐pressure liquid chromatography (HPLC) of autoxidized methyl oleate, linoleate and linolenate and photosensitized‐oxidized linoleate are extended to photosensitized‐oxidized linolenate. Photosensitized‐oxidized linolenate was fractionated by silicic acid chromatography with diethyl ether/hexane mixtures. Selected silicic acid chromatographic fractions were separated by polar phase HPLC and characterized by thin layer and gas liquid chromatography and by ultraviolet, infrared, nuclear magnetic resonance and mass spectrometry. Secondary products from the photosensitized oxidation mixtures (containing 8.2 to 29.0% monohydroperoxides) included keto‐ and epoxy‐dienes (0.4–1.6%), hydroperoxy epidioxides (0.8–4.9%), hydroperoxy bicyclic monoenes (0.1–0.3%), dihydroperoxides (1.0–5.6%), and hydroperoxy bisepidioxides (0.7–1.6%). Some of these secondary products are new and unique to photosensitized oxidation. Cyclization of the 10‐, 12‐, 13‐ and 15‐hydroperoxides of linolenate would account for their lower relative concentration than that found for the 9‐ and 16‐hydroperoxides. Dihydroperoxides may be derived from monohydroperoxides by singlet oxygenation or free radical oxidation. The hydroperoxy bis‐epidioxides may be formed by further serial cyclization of the hydroperoxy epidioxides from 10‐ and 15‐monohydroperoxides. Dihydroperoxides, hydroperoxy epidioxides and hydroperoxy bis‐epidioxides are suggested as important flavor precursors in oxidized fats.
Cholesterol metabolism in gnotobiotic gerbils
Authors: Bartizal Kenneth F. , Beaver Margaret H. , Wostmann Bernard S.
Published: December 2006

Germfree gerbils were associated with a murine‐derived hexaflora which produced only minor changes in the primary bile acid pattern of rats. These hexaflora‐associated gerbils had relatively small ceca (4% of body weight) and reproduced well. Although serum cholesterol levels of both conventional and hexaflora‐associated gerbils increased in response to dietary cholesterol, the hexaflora‐associated gerbil showed a greater elevation in serum cholesterol than the conventional gerbil when maintained on a diet containing 0.1% cholesterol. This increase in serum cholesterol manifested itself almost totally in the very low density lipoprotein and low density lipoprotein fractions. The fecal bile acids of the hexaflora‐associated gerbil were largely deconjugated, but very little further modification of either cholic or chenodeoxycholic acid had taken place. The data suggest that in the absence of elements of the intestinal microflora that can express a bile acid‐modifying potential, and particularly a 7‐α‐dehydroxylating capacity, catabolism of cholesterol to bile acids is reduced, and cholesterol accumulates in the very low density and low density serum lipoprotein fractions.
Synthesis and identification of bis (diacylglycero) phosphoric acid and bis (monoacylglycero) phosphoric acid
Authors: Dang Quoc Quan , Rogalle Pierre , Salvayre Robert , Dousteblazy Louis
Published: December 2006

Synthesis of bis‐(diacylglycero)phosphoric acid fromsn‐1,2‐dipalmitoylglycerol and phenylphosphoryl dichloride according to Baer (1) was revised. New data are reported about identification of the intermediate and final products: (a) bis‐phosphatidic acid phenyl ester is very slowly visualized by the Zinzade reagent and can escape notice; (b) large amounts of phosphatidic acid chloride phenyl ester are also formed; and (c) very little transacylation fromsn‐1,2‐dipalmitoyl‐glycerol to the 1,3‐isomer is observed. Hydrolysis of bis‐phosphatidic acid to bis‐lysophosphatidic acid is much easier using phospholipase A2 from pig pancreas than from snake or bee venom.
Increased thromboxane B2 biosynthesis in platelets
Authors: Kawaguchi H. , Ishibashi T. , Imai Y.
Published: December 2006

The synthesis of thromboxane B2 is increased in platelets from rabbits with experimental hypercholesterolemia, but the increase is not due to increased phospholipids hydrolysis. We have clarified the mechanism for the increased thromboxane synthesis. The biosyntheses of prostaglandin H2 and thromboxane B2 were unaffected by supperoxide dismutase, xanthine oxidase, mannitol, or benzoate in other experiments designed to study the possible involvement of reactive oxygen species. These results suggest that O2.− and OH. were not likely to be involved as intermediates in the synthesis of prostaglandin H2 and thromboxane B2 in platelets. The rate of prostaglandin H2 biosynthesis was promoted in deuterium oxide, and this deuterium oxide enhancement effect was reversed by 2,5‐diphenylfuran, suggesting that singlet oxygen may be involved in prostaglandin H2 biosynthesis. The biosynthesis of prostaglandin H2 was promoted by ADP‐Fe3+ but inhibited by EDTA and EDTA‐Fe3+. The effect of ADP‐Fe3+ could not be replaced by EDTA‐Fe3+. The effects of glutathione, glutathione peroxidase and H2O2 on cyclooxygenase and thromboxane synthetase were studied by using partially purified enzymes and platelet microsomes. Glutathione and glutathione peroxidase inhibited the activity of cyclooxygenase but did not inhibit that of thromboxane synthetase. H2O2 caused the inactivation of cyclooxygenase, but the addition of H2O2 did not inhibit the formation of thromboxane B2 from prostaglandin H2. An examination of glutathione concentration and glutathione peroxidase activity in platelets from normal and experimentally hypercholesterolemic rabbits demonstrated that both were decreased in platelets from later group. The observed alterations in glutathione levels and glutathione peroxidase activity are large enough to cause increased thromboxane B2 synthesis in platelets but the possibility that other unidentified factors may also contribute cannot be excluded.
Morphology and fatty acid composition of reticulocytes from phenylhydrazine‐treated rats
Authors: Goheen S. C. , Larkin E. C. , Rao G. Ananda
Published: December 2006

Reticulocytosis was induced in rats by injecting phenylhydrazine, a potent oxidizing agent. Red cell morphology was analyzed by scanning electron microscopy. The majority of red cells from rats given injections of phenylhydrazine were types 2 and 3 echinocytes. Stomatocytes were also observed, but pitted lobular reticulocytes were not detected. Echinocytes have not previously been observed in reticulocyte populations. In the reticulocytes, the relative levels of 16∶1 and 18∶1 were significantly greater than in erythrocytes. These differences in monoenoic acids may be due to the presence of endoplasmic reticulum, the site of desaturase activity in reticulocytes. Of all the fatty acids, the polyunsaturates are the most susceptible to attack during peroxidation. However, the polyunsaturated fatty acid composition of reticulocytes was similar both to that of erythrocytes and to reported values of young erythrocytes isolated by density. Therefore, it is unlikely that lipid peroxidation caused the formation of echinocytes.
Rat adipocyte utilization of different substrates: Effects of cell size and the control of lipogenesis
Authors: May James M.
Published: December 2006

The metabolism of labeled glucose, pyruvate and acetate was compared in adipocytes isolated from old, obese rats (>500 g) and young, lean rats (130–150 g). The larger cells from old, obese rats had markedly reduced rates of glucose, pyruvate and acetate conversion to glyceride‐fatty acids, indicating that large cell fatty acid formation is reduced at some point beyond the entry of pyruvate and acetate into glucose metabolism. No evidence of a primary block in the pentose phosphate cycle of cells from old, obese rats was found. In spite of diminished glucose metabolism to several products in the large cells, both basal and insulin‐stimulated rates of glyceride‐glycerol synthesis from glucose and pyruvate were similar in each cell type. This indicates a relative diversion of carbon flow to α‐glycerophosphate and reesterification in the large cells. Addition of low concentrations of glucose increased glyceride‐fatty acid synthesis from acetate (both cell types) or pyruvate carbon (small cells), but decreased glyceride‐glycerol synthesis from pyruvate carbon (both cell types). The acceleration of small cell fatty acid synthesis from pyruvate carbon by glucose and insulin was shown to be related to provision of NADPH from glucose metabolism in the pentose cycle. These studies indicate that, although the block in lipogenesis in adipocytes from old, obese rats appears to reside in the pathway of fatty acid synthesis itself, provision of additional α‐glycerophosphate or NADPH from glucose metabolism may, under certain conditions, increase lipogenesis in cells from old, obese and young, lean rats.
Cholesteryl ester hydrolase activity in adrenal homogenates from normal and essential fatty acid‐deficient female rats
Authors: Young Angela K. , Walker Brian L.
Published: December 2006

Cholesteryl ester hydrolase was assayed in adrenal homogenates from mature female rats fed a control (corn oil‐containing) or essential fatty acid (EFA)‐deficient diet. Cholesteryl ester of 16∶0, 18∶0, 18∶1, 18∶2(n−6), 20∶4(n−6) and 22∶4(n−6) were used as substrates. In control rats, the unsaturated esters were hydrolyzed more rapidly than the saturated esters and cholesteryl arachidonate was the preferred substrate of the six investigated; cholesteryl oleate elicited the highest activity in the deficient group. Polyunsaturated esters were hydrolyzed at a significantly lower rate by homogenates from EFA‐deficient rats than by those from control animals. The esters of 18∶1, 18∶2(n−6) and 20∶4(n−6) were hydrolyzed more extenstively in relation to their concentrations in adrenal tissue than were cholesteryl esters of 16∶0, 18∶0 and 22∶4(n−6). This difference was more pronounced in control than in EFA‐deficient rats. No simple relationship of adrenal cholesteryl ester hydrolase activity to ester fatty acid structure or to nutritional essentiality was evident.
Effect of detergents on in vitro 7α‐hydroxycholesterol formation by rat liver microsomes
Authors: Sanghvi Ajit , Grassi Enrico , Bartman Candace , Diven Warren F.
Published: December 2006

Formation of 7α‐hydroxycholesterol by rat liver microsomes was quantitated using a gas chromatograph‐mass spectrometer (GC/MS) operated in selected ion monitoring (SIM) mode. Microsomes from normal rat livers incubated for different periods were found to yield increased 7α‐hydroxycholesterol with time. This was also true when incubations contained Tween‐80, but in this instance, the rate of 7α‐hydroxycholesterol production was lower and dependent on the concentration of Tween used. Similarly, Triton X‐100, Renex‐30, Kyro EOB, Cutscum, and Emulgen 911 all lowered the formation of 7α‐hydroxycholesterol by rat liver microsomes, whereas Triton WR‐1339 stimulated its production. Analysis of data obtained from following the enzyme reaction over an extended period using an integrated Michaelis‐Menten equation indicated the enzyme possesses a very significant affinity for the product (Ks>Kp). Similar analysis shows that Tween‐80 is a noncompetitive inhibitor of the enzyme.
The quantitative determination of plasmalogen by its reaction with mercuric chloride
Authors: Carey Eric M.
Published: December 2006

The alk‐1‐enyl group of 1‐alk‐11‐enyl‐2‐acyl‐glycerophospholipids (plasmalogens) rapidly combines with mercuric chloride. At 0 C, there was a 1∶1 stoichiometry for Hg binding to the reactive enol group of plasmalogens. Aldehydes were not released, indicating that the alkenyl ether bond was not cleaved. Hg binding to less reactive double bonds in unsaturated fatty acids was not significant. Quantitative estimation of bound Hg afforded a rapid and sensitive assay for alkenylacyl lipids and gave values similar to those obtained with other methods of analysis. The proportion of plasmalogens in bovine myelin glycerophosphatides and in ethanolamine glycerophosphatide was 35 and 75%, respectively. Plasmalogens account for 23.3% of the total glycerophospholipid of rat erythrocytes.
Effect of altered sterol composition on the osmotic behavior of sphaeroplasts and mitochondria ofSaccharomyces cerevisiae
Authors: McLean‐Bowen Colleen A. , Parks Leo W.
Published: December 2006

The effect of sterols on the osmotic stability of mitochondrial and plasma membranes of yeast wild‐types and mutants that are defective in ergosterol biosynthesis has been studied. Incorporation of the nonfungal sterol, cholesterol, into yeast membranes reduces membrane elasticity which is observed as an increased susceptibility to osmotic lysis. However, the wild‐type and nystatin‐resistant strains which were examined indicate that qualitative alterations in endogenously generated sterols do not affect resistance to swelling. Although these strains exhibit differences in membrane fluidity, which is influenced by the sterol accumulated by the organisms, the membrane stretching capacity shows no distinct dependence on sterol structure or bilayer fluidity.
Uptake and oxidation of malonaldehyde by cultured mammalian cells
Authors: Bird R. P. , Draper H. H.
Published: December 2006

Primary cultures of rat skin fibroblasts were used as a model system to investigate the cellular uptake and oxidation of malonaldehyde (MA). The cells were grown in a medium containing 10−5 M, 10−4 M or 10−3 M concentrations of [1,3‐14C]MA. There was a limited, concentration‐dependent uptake of MA by 24 hr (∼4% at all concentrations). The uptake of [1,2‐14C]acetate by 24 hr was ∼24%; 83–89% of the14C in the MA taken up was oxidized to14CO2 by 24 hr and ∼5% was recovered in the major lipids. Despite its low uptake and rapid oxidation to CO2, pretreatment of the cells with 10−3 M MA for 24 hr produced a latent inhibition of [14C]glucose oxidation. Limited cellular uptake of MA may explain the tolerance of cells grown in culture to relatively high MA concentrations.
Selective deposition oftrans‐8‐ andcis‐9‐octadecenoates in egg and tissue lipids of the laying hen
Authors: Lanser A. C.
Published: December 2006

The deposition oftrans‐8‐octadecenoate‐8(9)‐3H (8t‐18∶1‐3H) was compared tocis‐9‐octadecenoate‐10‐14C (9c‐18∶1‐14C) in the major egg yolk neutral lipids and phospholipids and in organ lipids from the laying hen.trans‐8‐Octadecenoate was preferentially incorporated into only the phosphatidylethanolamines (PE), whereas discrimination against 8t‐18∶1‐3H occurred in the phosphatidylcholines (PC), triglycerides (TG) and cholesteryl esters (CE). The 1‐acyl position of both PE and PC contained three times more 8t‐18∶1‐3H than 9c‐18∶1‐14C. Almost total exclusion of the 8t‐18∶1‐3H from the 2‐acyl position of these phospholipids was found. Preferential incorporation of 9c‐18∶1‐14C occurred at the combined 1‐ and 3‐acyl positions and at the 2‐acyl position of yolk TG. Tissue lipid analyses indicated that there was preferential deposition of 9c‐18∶1‐14C into all organs. Individual liver lipid classes displayed the same relative order of discrimination against 8t‐18∶1‐3H as did egg yolk lipids (CE>TG>PC>PE).
Changes in liver lipids after administration of 2‐decanoylamino‐3‐morpholinopropiophenone and chlorpromazine
Authors: Hospattankar Ashok V. , Vunnam Ranga R. , Radin Norman S.
Published: December 2006

The enzyme which forms glucocerebroside, ceramide: UDP‐glucose glucosyltransferase, is inactivated in vitro by a cationic analog of cerebroside, 2‐decanoylamino‐3‐morpholinopropiophenone. A study of the inhibitor using intraperitoneal injection into young mice showed that the level of the enzyme activity in liver was appreciably lowered between 3 and 6 hr after injection. The activity increased subsequently, overshooting the normal level within 24 hr by about 20%, then returning to normal within the next 24 hr. Additional effects observed in liver were an increase in lipid content (primarily in the triglyceride fraction and ceramides) and a decrease in the glucocerebroside level. Body temperature dropped rapidly. Markedly similar effects were produced by injecting chlorpromazine, which was tried in order to reduce the hyperirritability and inhibitory effects on monoamine oxidase previously demonstrated by the glucosyltransferase inhibitor. Chlorpromazine did indeed block the hyperirritability and resulted in enhancement of the keto amine's effects on the enzyme and lipids. It is possible that the two drugs in combination would be helpful in ameliorating the symptoms due to the cerebroside accumulation that occurs in Gaucher disease. Diazepam also produced a reduced level of glucosyltransferase. A color reaction for chlorpromazine, possibly suitable for quantitative determination in tissues, was accidentally discovered.
Stereospecificity of premature human infant lingual lipase
Authors: Jensen Robert G. , Dejong F. A. , Clark R. M. , Palmgren Lisa G. , Liao Teresa H. , Hamosh Margit
Published: December 2006

The lingual lipase in gastric aspirates from premature infants was found to be partially stereospecific forsn‐3 esters of synthetic enantiometric triacylglycerols containing 18∶1 and 16∶0. Thesn‐3 ester was hydrolyzed about 4 times faster than the acid at thesn‐1 position with no difference in rates between 18∶1 and 16∶0. Thesn‐2 was also hydrolyzed to some extent.
Fatty acid composition of serum lipids in fasting ponies
Authors: Bauer John E. , Ransone Welford D.
Published: December 2006

Alterations in the fatty acid distribution of total lipid extracts and 4 of the major lipid subclasses of serum in ponies fasted overnight and for 4 and 7 days were determined. Although increases in 16∶0, 16∶1, and 18∶3ω3 were observed, decreased amounts of 18∶0 and 18∶2ω6 combined to cause no significant change in the saturated to unsaturated fatty acid ratio in the total extracts. Phospholipid became somewhat preferentially enriched in saturated fatty acids due to a decrease in 18∶1, although this response was variable. The free fatty acid and triglyceride fractions both showed increases in relative amounts of 18∶3ω3 and a alteration was most likely due to the mobilization of an increased proportion of polyunsaturated fatty acids from tissue sites with their subsequent incorporation into triglyceride by the liver. It probably reflects the type of forage diet on which the animals had been maintained prior to the study. The fatty acid composition of the cholesteryl ester fractions was unchanged during fasting but contained appreciable amounts of the 18∶2ω6 fatty acid.
Inhibition by adenosine triphosphate of heart microsomal neutral lipase activity
Authors: Murthy Veeraraghavan K. , Stiles Mark R. , Shipp Joseph C.
Published: December 2006

Triacylglycerol lipolysis was inhibited by palmitate, in the isolated perfused normal rat heart. Acetate or acetylcarnitine could reproduce the inhibitory effects of palmitate. Since heart neutral lipase plays an important role in the lipolysis of heart triacylglycerols, the effects of acetylcarnitine, acetyl CoA and related metabolites on the microsomal neutral lipase activity were studied. ATP inhibited the enzyme activity in a concentration‐dependent manner without a lag phase. AMP and adenylyl imidodiphosphate, two compounds structurally related to ATP but whose phosphate groups cannot be transferred, did not inhibit the microsomal lipase activity. These results suggested that ATP inhibited the lipase activity through the transfer of its phosphate group. It is proposed that cellular ATP concentration is a determinant of tricylglycerol lipolysis in the heart.
Fatty acid composition of tissue phospholipids and prostaglandin excretion in hyperlipidemia induced in rats by implantation of the mammotropic pituitary tumor MtT‐F4
Authors: Huang Y. S. , Martineau A. , Falardeau P. , Davignon J.
Published: December 2006

A mammotropic pituitary tumor, MtT‐F4, was implanted into male Fisher 344 rats for a period of 4 weeks. This tumor induced growth retardation, hyperlipidemia, hepatic hypertrophy and adrenal hyperplasia. Lipids were extracted from various tissues. In tumor‐bearing rats, phospholipid concentration was found to be increased in plasma, spleen and testis. Distribution among the various phospholipid classes was similar to that of controls except in liver and heart, where phosphatidylcholine was increased at the expense of phosphatidylinositol and phosphatidylserine. The main difference was in the fatty acid composition of major phospholipids. The proportion of ω6 fatty acids was lower and that of docosahexaenoic acid of the ω3 series (22∶6ω3) was higher in most tissues, especially in plasma, liver, heart and kidney. Concurrently, the urinary excretion of two endogenous metabolites of PGI2 (2,3‐dinor‐6‐keto‐PGF1α and 6,15‐diketo‐13,14‐dihydro‐2,3‐dinor‐PGF1α) was found to be increased significantly in tumor‐bearing rats. The results raise the hypothesis that hormonal changes induced by the MtT‐F4 tumor accelerate the conversion of arachidonic acid (20∶4ω6) to prostaglandins. This effect, perhaps coupled with a diversion of linoleic acid (18∶2ω6) towards other metabolic processes, would account for a partial depletion of membrane phospholipids in 18∶2ω6 and for the reduced production of longer chain ω6 unsaturated acids from 20∶4ω6, creating a state of “relative essential fatty acid deficiency.” As a result, the metabolism of ω3 fatty acids is altered towards an enhanced production of 22∶6ω3 which accumulates in the lipids of cell membranes to compensate for the depletion of unsaturated acids of the ω6 series.
Modification of microsomal lipid composition and electron transport enzyme activities in isovalerate‐supplemented cells of novelTetrahymena ISO
Authors: Watanabe Takehito , Fukushima Hirofumi , Sasaki Noboru , Umeki Shigenobu , Suezawa Yoshie , Nozawa Yoshinori
Published: December 2006

Tetrahymena ISO cells, which have an unusually high level ofiso odd‐numbered fatty acids, were grown medium supplemented with various concentrations of isovalerate. There was a marked increase in the total proportion ofiso odd‐numbered fatty acids in supplemented whole cells (28.9→70.3%) and microsomes (37.7→84%), with a corresponding decrease in normal fatty acids, although no significant alteration of phospholipid composition was observe during 11 hr isovalerate‐supplementation. Microsomal palmitoyl‐CoA and stearoyl‐CoA desaturase activities in isovalerate‐supplemented cells decreased by 45.7% and 30.6% during 11 hr, respectively. NADH‐cytochrome c reductase and NADH‐ferricyanide reductase activities as well as the content of cytochrome b560ms, which is similar to mammalian microsomal cytochrome b5, were reduced in microsomes from 11 hr‐supplemented cells, whereas NADPH‐cytochrome c reductase activity was constant. It is suggested that the alteration of the cross‐sectional area of lipid molecules in the bilayer, which results from the replacement of normal fatty acids withiso‐15∶0 andiso‐17∶1, would result in the decline of palmitoyl‐ and stearoyl‐CoA desaturation in the isovalerate‐supplemented cells, in order to maintain membrane fluidity at a functional level.
Effects of lysophosphatidylcholine on jejunal water and solute transport in the rat in vivo
Authors: Ammon H. V. , Loeffler R. E. , Luedtke L. A.
Published: December 2006

The effects of lysophosphatidylcholine on jejunal water and solute transport were studied in vivo in the rat. Five mM lysophosphatidylcholine significantly reduced absorption of water, electrolytes and glucose (P<0.05) and 10 mM lysophosphatidylcholine induced net fluid secretion. The effects of 10 mM lysophosphatidylcholine were significantly reduced in the presence of 5 mM phosphatidylcholine (P<0.05) and 2 mM cholesterol (P<0.05). The fractional absorption of lysophosphatidylcholine decreased with increasing concentration of the detergent in the perfusion solution. Increasing concentrations of taurocholate in the perfusion solutions potentiated the effects of lysophosphatidylcholine (P<0.01), although 10 mM taurocholate by itself had no significant effect on intestinal water and electrolyte transport. The data establish that lysophosphatidylcholine, a zwitterionic detergent, affects intestinal transport in the same way as bile acids, fatty acids and synthetic cationic or nonionic detergents. By comparison with the response of the human jejunum to taurodeoxycholate, it is likely that lysophosphatidylcholine generated during the normal process of digestion has an effect on intestinal water and solute transport in man.
Influence of stage of lactation on the triacylglycerol composition of buffalo milk fat
Authors: Arumughan C. , Narayanan K. M.
Published: December 2006

Milk fats obtained from colostrum and early, middle and late lactation samples of buffalo milk were analyzed for their triacylglycerol (TG) compositions. Each milk fat first separated by thin layer chromatography (TLC) into high, medium and low molecular weight TG. The TG fractions thus obtained were further segregated by argentation TLC, according to their degree of unsaturation into saturated,trans‐monoene,cis‐monoene, diene and polyene species. With progressive lactation, the major changes from colostral fat were an increase in lower fatty acids and decline in oleic acid. This caused, in turn, marked variations in saturated TG and diene TG and, to a smaller extent, in polyene TG. Monoene TG, bothcis andtrans, remained practically constant throughout. These trends were largely reversed toward the end of lactation.
Differential effects of dietary fatty acids on the accumulation of arachidonic acid and its metabolic conversion through the cyclooxygenase and lipoxygenase in platelets and vascular tissue
Authors: Galli C. , Agradi E. , Petroni A. , Tremoli E.
Published: December 2006

Semisynthetic diets containing either corn oil (CO) or butter (B) (11 and 2.2 en % as linoleic acid, respectively) were fed to male rabbits for periods of 3 weeks and 3 months. The CO diet, in respect to the B diet, induced higher levels of linoleic acid (LA) and lower levels of arachidonic acid (AA) in platelet phospholipids, lower levels of AA in aortic phosphatidylinositol (PI) and accumulation of both LA and AA in liver lipids. The thresholds for aggregation with AA, but not with collagen, were higher in the CO group and the formation of thromboxane B2 (TXB2) from [14C] AA, but not from endogenous substrate after collagen stimulation, was lower in the same group. Formation of PGE2‐like material by incubated aortas was higher in the B group. In the CO group, platelet cyclooxygenase appeared to be selectively depressed. The correlations among diet‐induced fatty acid changes in platelet and aortic lipids, platelet aggregation and thromboxane and prostacyclin formation are discussed.