bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition by 5‐(tetradecyloxy)‐2‐furoic acid of fatty acid and cholesterol synthesis in isolated rat hepatocytes
Authors: Panek Edwige , Cook George A. , Cornell Neal W. 
Published: November 2006

AbstractFatty acid and cholesterol synthesis in isolated rat hepatocytes were strongly inhibited by 5‐(tetradecyloxy)‐2‐furoic acid. With either3H2O or [2‐14C]acetate as the labeled precursor, the concentrations of inhibitor causing 50% decrease in fatty acid and cholesterol synthesis were, respectively, <0.005 mM and 0.020 mM. At 0.1 mM inhibitor, citrate concentration in cells from fed rats was increased by 75%; lactate and pyruvate concentrations were decreased by 30%; ethanol oxidation was decreased by 20%; with cells from starved rats, the mitochondrial [NAD+]/[NADH] was decreased. Other parameters were unaffected. Both its potency and its specificity indicate that 5‐(tetradecyloxy)‐2‐furoic acid will be useful in studies on the regulation of lipid biosynthesis.
Activity of phospholipid‐synthesizing enzymes in rat liver plasma membranes and the source of biliary lecithin
Authors: Yousef I. M. , Fisher M. M. , Piekarski J. , Holub B. J. 
Published: November 2006

AbstractThe potential for the synthesis of phosphatidylcholine by the bile canalicular membrane of the liver cell was assessed by measuring the activity of a number of phospholipid synthesizing enzymes in isolated bile canalicular membrane fractions from rat liver. The activity of these various enzymes was compared to that present in noncanalicular liver cell plasma membranes and in microsomes. The CDP‐choline: 1,2‐diacyl‐sn‐glycerol‐cholinephosphotransferase was virtually absent from the bile canalicular membranes but the specific activities of S‐adenosyl‐L‐methionine:phosphatidylethanolamine N‐methyltransferase and acyl‐CoA:1‐acyl‐sn‐glycero‐3‐phosphoryl‐choline acyltransferase were 11–15% of those found in the microsomes. The bile canalicular membranes also contained detectable acyl‐CoA:sn‐glycero‐3‐phosphate acyltransferase activity and the ability to potentiate the Ca++‐stimulated exchange of bases between different phospholipids. These findings indicate that the bile canalicular membranes have a very limited capacity for the formation of phosphatidylcholine under the assay conditions employed.
Changes in the acyl and alkenyl group composition of cardiac phospholipids in boars fed corn oil or rapeseed oil
Authors: Kramer John K. G. , Hulan Howard W. 
Published: November 2006

AbstractBoars fed diets containing rapeseed oil for 8 weeks showed significantly higher levels of neutral lipids and similar levels of phospholipids, compared to those fed corn oil. Erucic and eicosenoic acids were found to be high in ethanolamine phosphoglycerides, and in particular alkenyl acyl‐ethanolamine phosphoglyceride. Furthermore, both long chain monoenes were incorporated preferentially in position 2 of the choline and ethanolamine phosphoglycerides. The alkenyl group composition of the cardiac lipids of pigs was influenced by dietary fatty acids. When rapeseed oil was fed, small amounts of 20∶1 and 22∶1 alkenyl constituents were detected.
Lipid and fatty acyl composition of rat brain capillary endothelia isolated by a new technique
Authors: Selivonchick Daniel P. , Roots Betty I 
Published: November 2006

AbstractA method is described for the isolation of pure capillary endothelia from rat brain and the phospholipid composition of these cells is reported. This method is rapid and requires only a small amount of starting material. It involves: (a) tissue disruption by high speed homogenization, (b) separation of the capillary endothelia from other brain structures using sucrose gradients, and (c) a final purification using a glass bead column. Choline and ethanolamine phosphoglycerides were found to be the predominant lipid classes of these cells amounting to 31.9% and 24.4%, respectively, of total phospholipids. The choline phosphoglycerides consisted almost exclusively of 1,2‐diacyl glycerophosphorylcholine, whereas the ethanolamine phosphoglycerides consisted of approximately equal amounts of 1,2‐diacyl and 1‐alk‐l'‐enyl‐2‐acyl glycerophosphorylethanolamine. The composition of the constituent fatty acids of both choline and ethanolamine phosphoglycerides and the alk‐1‐enyl composition of ethanolamine phosphoglycerides is reported. Saturated fatty acids accounted for 45% of the total fatty acids in choline phosphoglycerides and for 53% in ethanolamine phosphoglycerides. Arachidonic acid accounted for approximately 48% of the total fatty acids in alk‐1‐enyl ethanolamine phosphoglyceride.
Thin layer chromatographic procedure for class separation of plant neutral lipids
Authors: Schlotzhauer P. F. , Ellington J. J. , Schepartz A. I. 
Published: November 2006

AbstractA thin layer chromatographic method has been developed for the class separation of plant neutral lipids. Utilizing a two‐step development in one dimension, lipid mixtures are separated into hydrocarbon waxes, steryl esters, methyl esters, triglycerides, fatty acids, diglycerides, sterols, and monoglycerides. The method may be employed for either qualitative or preparative purposes.
Autoxidation of fatty acid monolayers adsorbed on silica gel: I. Nature of adsorption sites
Authors: Wu Guey‐Shuang , Mead James F. 
Published: November 2006

AbstractAn unsaturated fatty acid monolayer deposited on a silica gel surface has been chosen as a model for studying nonenzymatic autoxidation of membrane lipids. Studies to determine the suitability of this system as a model for biomembranes were conducted to define the nature of the monolayers, particularly with respect to the factors determining the concentration of the fatty acid molecule on unit area of the surface. The results from adsorption isotherm, high temperature dehydroxylation, and infrared spectra studies show that adsorption of a monomolecular layer of fatty acids occurs and that the number of molecules absorbed corresponds to the number of isolated, non‐hydrogen‐bonded silanol groups. it is presumed the binding is by hydrogen bonding of the carboxyl groups to silanol groups. The packing density of the fatty acid molecules is 1.25 molecule/100 Å2 which is similar to the density of the isolated silanol sites on the surface.
Triglyceride composition of bovine milk fat with elevated levels of linoleic acid
Authors: Morrison I. M. , Hawke J. C. 
Published: November 2006

AbstractThe effect of increasing the linoleic acid (18∶2) content of milk fat on the composition and structure of the triglycerides (TG) was investigated. Protected sunflower seed supplement was added to the diet of a cow grazing on pasture, and the structure and composition of the milk fat compared with the milk fat from its monozygous twin which had been fed a control diet. The relative proportions of TG fractions of high, medium, and low molecular weight in the milk fat with elevated levels of 18∶2 (15.5% 18∶2) were 43.0, 19.5, and 37.5 moles %, respectively, compared with 36.1, 19.7, and 44.2 moles %, respectively, in the milk fat from the cow fed the control diet. Separation of these three TG fractions of each milk fat into TG classes with different levels of unsaturation showed that the milk fat with elevated levels of 18∶2 contained higher proportions of diene, triene, and tetraene TG and correspondingly lower proportions of saturated and, to a lesser extent, monoene TG. The saturated and monoene TG from the two milk fats had similar fatty acid compositions. However, the diene TG of the 18∶2‐rich milk fat included high proportions of the combination of 18∶2 with two saturated fatty acids (FA) which are minor constituents of normal milk fats. Likewise, the triene TG reflected the presence of 18∶2 in combination with 18∶1 and a saturated FA.
Reactions between peroxidizing lipids and histidyl residue analogues: Enhancement of lipid oxidation and browning by 4‐methylimidazole
Authors: Yong Samuel H. , Karel Marcus 
Published: November 2006

AbstractAs a part of our study on the interactions between peroxidizing lipids and the histidyl imidazole side‐chain in simple, low‐moisture model systems, 4‐methylimidazole (4MI) was reacted with methyl linoleate (ML). This analogue was chosen to avoid interference from other functional groups in histidine (free base) or in proteins. Changes in the concentrations of lipid hydroperoxides, carbonyls, 4MI, and brown pigments were followed over a period of 24 days. The results indicate that 4MI exhibits significant prooxidative activity by reducing the induction period as well as by enhancing the formation of brown pigments. These effects are more pronounced at high 4MI/ML molar ratios and under basic pH's. Upon interactions with peroxidizing ML, as much as 44% of initially present 4MI was destroyed by the sixth day of incubation.
Distribution of bile acids in rats
Authors: Uchida K. , Okuno I. , Takase H. , Nomura Y. , Kadowaki M. , Takeuchi N. 
Published: November 2006

AbstractDistribution and biliary and fecal excretion of bile acids were examined in Wistar strain male rats of about 300 g body weight. The pool size of the rats on ordinary diet was 40 mg/rat, biliary secretion was 14 mg/hr, and fecal excretion was 10 mg/day. Bile acids were mainly located in the small and large intestinal contents, 87% and 10%, respectively; but a portion was found in the intestinal wall and the liver. Rats fed 2% cholesterol‐supplemented diet for a week showed similar values for pool size and biliary secretion with the rats on ordinary diet, but higher values for fecal excretion and distribution ratio in the large intestinal contents. Cholic acid was a major component in the bile, small intestinal wall, small intestinal content and liver, while the bile acid composition ratios were roughly similar to each other, although a relatively large amount of α‐muricholic acid was found in the intentinal wall and liver. Both the wall and content compositions of the large intestine were similar to that of the feces, in which lithocholic, deoxycholic, α‐ and β‐muricholic acids were the main components, although the ratios of α‐ and β‐muricholic acids in the large intestinal wall were larger than those in the intestinal contents or feces. The high concentrations of these bile acids may indicate a difference of transport velocity across the cell membrane, but the mechanism is not known.
Resolution of molecular species of intact serine and ethanolamine phosphatides by argentation chromatography of their trifluoroacetamides
Authors: Yeung S. K. F. , Kuksis A. , Marai L. , Myher J. J. 
Published: November 2006

AbstractAn effective resolution of intact phosphatidylserines on the basis of unsaturation has been achieved by conventional argentation thin layer chromatography (TLC) following trifluoroacetylaction. The trifluoroacetamides are prepared by treatment with trifluoroacetic anhydride or N‐methyl‐bis‐trifluoroacetamide. The acetamides are resolved with chloroform‐methanol‐water (65∶25∶4, v/v/v) on Silica Gel G containing 20% silver nitrate. Subfractions with 0–6 double bonds per molecule were obtained for the phosphatidylserines of pig and ox brain, pig erythrocytes, rat liver, and rabbit skeletal muscle. The preparation of trifluoroacetamides is also advantagenous for the silver ion fractionation of phosphatidylethanolamines. The method is applicable to metabolic studies of molecular species using radioactive precursors of neutral lipids, phosphorus, and nitrogenous bases.
Levels of cyclic 3′‐5′‐adenosine monophosphate (cAMP) in maintenance cultures of rat hepatocytes in response to insulin and glucagon
Authors: Geelen Math J. H. , Vaartjes Willem J. , Gibson David M. 
Published: November 2006

AbstractUnder conditions of short‐term stimulation of lipogenesis by insulin in maintenance cultures of hepatocytes from starved rats, basal levels of cyclic 3′‐5′‐adenosine monophosphate (cAMP) are invariant. Glucagon signals increased levels of cAMP and severely diminishes lipogenesis. Insulin partially counteracts both glucagon effects.
Progressive gross changes in renal medullary composition in pregnant rats
Authors: Chang Celia , Pike Ruth L. , Clagett Carl O. 
Published: November 2006

AbstractThe biochemical composition of the renal medulla and the blood pressures of pregnant rats and nonpregnant controls were compared on days 15, 18, 20, and 22 of pregnancy. Deoxyribonucleic acid and protein content of the renal medulla changed together with the tissue weight (wet weight) during gestation except on day 20 when a slight increase in protein was observed. However, the glycerophospholipids (phosphatidyl ethanolamine, phosphatidyl choline, and phosphatidyl serine) and sphingomyelin showed significant increases throughout the latter stages of pregnancy with the maxima in most cases occurring on day 20 of the gestation period. Medullary hypertrophy and increased lipid content per cell coexist with the decrease in blood pressure and may indicate peak activity in production of antihypertensive renal lipids.
Occurrence of 5,9,19‐octacosatrienoic, 5,9‐hexacosadienoic and 17‐hexacosenoic acids in the marine spongeXestospongia halichondroides
Authors: Litchfield Carter , Marcantonio Eugene E. 
Published: November 2006

AbstractThe marine spongeXestospongia halichondroides contains 13% 28∶3Δ5,9,19, 27% 26∶2Δ5,9, and 21% 26∶1Δ17 in its total fatty acids. Thecis‐5,cis‐9,cis‐19‐octacosatrienoic acid structure is unknown in other living organisms.
Diet and sterol biohydrogenation in the rat: Occurrence of epicoprostanol
Authors: Sulpice J. C. , Ferezou J. , Lutton C. , Mathé D. , Chevallier F. 
Published: November 2006

AbstractThe fecal sterols from rats fed several types of semipurified or commercial diets were analyzed by a combination of thin layer and gas liquid chromatography. In rats fed semipurified diets with lard, sucrose, and casein, increasing proportions of lard (0, 8, 20, 65%) enhanced the fecal coprostanol/coprostanol + cholesterol ratio (from 0.50 to 0.85). This ratio was reduced by replacing lard with triolein or a mixture of calcium oleate and linoleate (1∶1) and did not change when trierucin was substituted. No coprostanol formation was observed in rats fed a diet with tripalmitin or tristearin. The addition of sodium hyodeoxycholate (0.5%) or cholestyramine (2%) to the basal diet was without effect on the coprostanol/coprostanol + cholesterol ratio in the feces. The addition of sodium taurocholate (0.2, 0.75, and 4%) strongly reduced coprostanol formation, while a chronic bile duct ligation led to an enhancement. Cholesterol feeding (0.05, 0.2, and 0.5% in the diet) slightly increased (from 51 to 66%) coprostanol formation. Trace amounts of epicoprostanol were generally found in the feces. However, in some cases a very high proportion (up to 60%) of this sterol was observed. Possible relationships between the presence of epicoprostanol and the nature of the diet are discussed.
Effect of early postnatal dietary sterculate on the fatty acid composition of rat liver and brain lipids
Authors: Pullarkat Raju K. , Maddow Jane , Reha Henry 
Published: November 2006

AbstractPregnant rats were fed a high carbohydrate diet containing either 1% trilinolein or 1% trilinolein with 0.2% methyl sterculate from 18 day gestation to 21 day postpartum. The pups were weaned at 21 days and continued on the same diet for an additional 10 days. The microsomal stearyl CoA desaturase activities of the liver were effectively inhibited. Liver triglycerides showed increases in the saturated fatty acids concentrations at the expense of the corresponding monoenes. The concentration ofcis 6–7 octadecenoic acid was elevated. In liver phospholipids, the concentration of stearic acid was increased without a corresponding decrease in the oleic acid content. A drastic decrease in the nervonic acid (24∶1, n−9) concentration of liver sphingomyelin was observed. The lipids of the brain did not contain sterculic acid, and brain desaturase activity was unaffected. There was no significant change in the concentration of monoenoic acids from 16∶1 to 22∶1. However, nervonic acid was decreased by 32%. These results suggest that brain nervonic acid may be derived from a precursor other than oleic acid.
Diester waxes containing 2‐hydroxy fatty acids from the uropygial gland secretion of the white stork (Ciconia ciconia)
Authors: Jacob Jürgen 
Published: November 2006

AbstractThe uropygial gland of the white stork secrets mono‐ and diester waxes as well as triglycerides, all of which contain unbranched medium chain fatty acids. n‐Decanol and n‐dodecanol have been the only alcohols detected in both types of waxes. The diester waxes contain 2‐hydroxy fatty acids.
Identification of 15‐Keto‐9,11‐Peroxidoprosta‐5,13‐dienoic acid as a hematin‐catalyzed decomposition product of 15‐hydroperoxy‐9,11‐peroxidoprosta‐5,13‐Dienoic acid
Authors: Graff G. , Dunham E. W. , Krick T. P. , Goldberg N. D. 
Published: November 2006

AbstractA labile prostaglandin was isolated as one of the products generated from [1‐14C] eicosatetraenoic acid incubated with sheep vesicular gland microsomes. The eicosatetraenoic acid metabolite amounted to ca. 16% of the total radiolabeled products. Formation of this new prostaglandin was prevented when heat‐denatured microsomes were employed or when incubation mixtures were supplemented with indomethacin or phenol. However, incubation of prostaglandin G2 (PGG2) with hematin in the presence or absence of catalytically active or heat‐inactivated microsomes led to production of approximately the same quantity of the new prostaglandin. These results indicated that the new prostaglandin can be formed nonenzymically. The new prostaglandin was conclusively identified by gas liquid chromatography‐mass spectrometry analysis as 15‐keto‐9,11‐peroxidoprosta‐5,13‐dienoic acid (15‐keto‐PGG2) after chemical conversion to known prostaglandins. The effects of 15‐keto‐PGG2 and PGG2 were similar on canine lateral saphenous vein; both promoted contraction followed by prolonged relaxation, but 15‐keto‐PGG2 appeared to be 1/50 as potent as PGG2.
Separation of tetra‐, penta‐, and hexaacyl triglycerides by high performance liquid chromatography
Authors: Payne‐Wahl Kathleen , Plattner Ronald D. , Spencer Gayland F. , Kleiman Robert 
Published: November 2006

AbstractSynthetic triglycerides with more than three acyl groups were prepared by forming estolides from triglycerides containing one, two, or three monohydroxy fatty acyl moieties. These tetra‐, penta‐, and hexaacyl triglycerides were examined by high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). HPLC separation by the number of acyl groups was obtained with both conventional phase and reverse phase columns. In all systems, triglycerides were eluted first, followed in sequence by tetra‐, penta‐, and hexaacyl triglycerides. Within each glyceride class, further separation occurred due to variations in chain length and degree of unsaturation among the component acids. TLC migration on silica gel was found to be a function of the number of acyl groups and the length of component acid chains.
The effect of clofibrate on heart and plasma lipids in rats fed a diet containing rapeseed oil
Authors: Christiansen Renata Z. , Norseth Jon , Christiansen Erling N. 
Published: November 2006

AbstractThe effect of clofibrate on heart and plasma lipids in rats fed a diet containing 30% of the calories as peanut oil (PO) or rapeseed oil (RSO) (42.7% erucic acid and 0.5% eicosenoic acid) was studied. A decrease of erucic acid content to one‐third and concomitant increase in the content of 18∶1, 16∶1 and 16∶0 fatty acids in plasma triacylglycerols were observed after administration of clofibrate to rats fed the RSO‐diet. It is suggested that these changes reflect the increased capacity of the liver to chainshorten very long chain length fatty acids. The extent of lipidosis in the heart of rats fed the RSO‐diet was decreased by 50% by clofibrate. However, the concentration of erucic acid in heart triacylglycerols decreased much less (30%) than the concentration of all other fatty acids (50–65%). It is concluded that the clofibrate administration increased the oxidative capacity of the heart mitochondria and that the heart cell does not have an efficient system to handle very long chain length monounsaturated fatty acids as does the liver.
Stimulation of lipid absorption in young rats by cholesterol: Early time changes and effects on pentobarbital sleeping time
Authors: Bitman Joel , Weyant Joan R. , Wood D. L. , Wrenn T. R. 
Published: November 2006

AbstractFour groups of young male and female rats were fed a chow diet (0), chow plus 10% corn oil (F), chow plus 1% cholesterol (C), or chow plus 1% cholesterol plus 10% corn oil (CF) for 1, 2, 4 and 8 days. After 2 dats, male F, C and CF rats exhibited a shorter anesthesia period (−20 to −30%) when given pentobarbital. By 4 days, male F and C rats had pentobarbital sleeping times (PB‐ST) 20% less than 0 rats. These effects were additive and CF rats had 40% shorter PB‐ST. Reduction of PB‐ST by cholesterol and corn oil was similar but slightly less in female rats. Liver lipid content doubled in 4 days in CF rats, and liver cholesterol was 4 times that of 0 rats. These changes and the increases in metabolism of barbiturate suggested changes in liver microsomal enzyme activities. Serum glutamic oxaloacetic and glutamic pyruvic transaminase, two enzymes reflective of liver damage, did not increase after 8 days on C, F or CF diets. Our results suggest that consumption of an animal sterol and a high lipid diet by laboratory rats, normally consuming a diet low in fat (3–4%), increases the ability of the animal to detoxify a barbiturate. Storage of absorbed dietary cholesterol in the liver may represent a major mechanism for maintaining extra hepatic cholesterol homeostasis.
High‐pressure liquid chromatography and ultraviolet spectrometry of ketonic C27 sterols
Authors: Hunter Irving R. , Walden Mayo K. , Bailey Glen F. , Heftmann Erich 
Published: November 2006

AbstractA method for the separation of ketonic C27 sterols was devised, based on high‐pressure liquid chromatography (HPLC) and ultraviolet absorption (UV). The adsorption column contained silica gel, particle size 10 μm, and the eluents were dichloromethane/n‐hexane/ethyl acetate (94∶5∶1) and dichloromethane/ethyl actate (99∶1) followed by dichloromethane/ethyl acetate (3∶1). The 5β‐sterols were eluted before the 5α‐analogs, sterols with isolated double bonds before conjugated carbonyl compounds, and ketones before hydroxy ketones. The effect of carbonyl groups on polarity depends on the position in the molecule and decreases in the order C‐3>C‐6>C‐7. The ultraviolet absorption spectra of eleven sterols were determined, and their absorbance at 254 nm and at 280 nm was used for analyzing the column effluent with a dual detector system.
Age‐related changes in glycerolipid formation in lean and obese zucker rats
Authors: Jamdar Subhash C. 
Published: November 2006

AbstractAge‐related changes in hepatic and adipose glycerolipid formation have been described in Zucker rats. Glycerolipid formation was measured in vitro in the presence of [14C]glycerol‐3‐phosphate, palmitate, ATP, CoA, and Mg2+ by using liver and adipose tissue homogenates derived from various age groups of animals. Hepatic glycerolipid formation increased after birth to reach a peak value at 1 day of age. This period was followed by a decline in the rates of glycerolipid formation. Hepatic glycerolipid formation increased again at the time of weaning and continued to rise up to 32 days in lean rats and 42–44 days in obese rats. Obesity in rats was recognizable at the age of 32 days and was associated with increased rates of glycerolipid formation in both liver and adipose tissue. As far as the changes in hepatic glycerolipid formation and triglyceride accumulation are concerned, obese rats showed more resemblance to 1‐day‐old rats than to lean animals of similar age groups. Glycerolipid formation decreased in liver and increased in adipose tissue with age in both lean and obese rats. These studies suggest that hepatic and adipose tissue glycerolipid formation is significantly influenced by age and obesity in Zucker rats.