bluuebunny/crossref_metadata_2025 huggingface dataset:
On the site of the microbiological reduction of cholesterol to coprostanol in the rat
Authors: Kellogg Thomas F.
Published: November 2006

The microbiological reduction of the 5‐ene bond of cholesterol (cholest‐5‐en‐3β‐ol) to form coprostanol (5β‐cholestan‐3β‐ol) occurs in the gastrointestinal tract of many species. Data are presented which show that this activity occurs predominantly in the ceca in cholesterol fed rats. This explains the report by others that the removal of the ceca causes coprostanol to disappear from the feces.
Sensitized photooxidation of α‐tocopherol and of 2,2,5,7,8‐pentamethyl‐6‐chromanol in ethyl acetate
Authors: Grams G. W. , Inglett G. E.
Published: November 2006

The major product of each photo‐oxidation was an equimolar mixture of quinone oxide and quinone. The yield of this mixture was 64% and 67% when the substrate was α‐tocopherol and 2,2,5,7,8‐pentamethyl‐6‐chromanol, respectively. Neither spirodienone dimer nor trimer was present in the product mixture. Evidently the reaction intermediate is an adduct of tocopherol and singlet oxygen. Tocopherol may protect biological lipids from singlet oxygen degradation.
Resistance of certain long‐chain polyunsaturated fatty acids of marine oils to pancreatic lipase hydrolysis
Authors: Bottino Nestor R. , Vandenburg Gloria A. , Reiser Raymond
Published: November 2006

When whale oil triglycerides were subjected to pancreatic lipase hydrolysis, eicosapentaenoic and docosahexaenoic acids were found mainly in the di‐ and triglyceride products, suggesting that they are in the 1,3‐positions but resistant to the action of the lipase. Their presence in the 1,3‐positions was confirmed. Their resistance to pancreatic lipase hydrolysis was demonstrated by analysis of the products of the enzyme action on: (a) a concentrate of highly unsaturated whale oil triglycerides; (b) the latter after randomization; and (c) synthetic 1,2‐di‐octadecenoyl‐3‐eicosapentaenoyl glycerol.

Docosapentaenoic acid was also shown to be present in the 1,3‐position of whale oil triglycerides but was not lipase resistant. It is postulated that the presence of a double bond near the carboxyl group exercises an inhibitory effect, or that the location of the double bonds in the resistant acids places their terminal methyl groups close to the carboxyl, producing a steric hindrance effect.
Intracerebrally injected monohydroxy and other C24 steroid acids as demyelinating agents in the guinea pig
Authors: Mujtaba Naqvi S. H. , Herndon B. L. , Del Rosario L. , Nicholas H. J.
Published: November 2006

Sodium salts of lithocholic acid (3α‐hydroxy‐5β‐cholanoic acid), 5β‐cholanoic acid, Δ5‐cholenoic acid and 3‐keto‐5β‐cholanoic acid injected intracerebrally into guinea pigs in doses of 1 mg or higher produced periventricular demyelination. 24‐14C‐sodium lithocholate was rapidly released from the brain (only traces remained 2 hr after injection) if injected in quantities ranging from 2 μg to 5 mg. This rapid elimination is believed to account for the relatively high dose of lithocholate required for producing demyelination, and may also account for the limited demyelinating capacity of the other acids injected intracerebrally.
Conjugation of polyunsaturated acids
Authors: Mounts T. L. , Dutton H. J. , Glover D.
Published: November 2006

The isomerization reaction of methyl linoleate and methyl linolenate with potassiumt‐butoxide has been investigated. The compositions of the reaction products formed at three temperatures have been determined and the relationships between these analyses and observed differences in absorptivities by UV spectrometry are discussed. Conclusions concerning the reaction mechanisms are based on compositional analysis and results of experiments using radioactive or stable isotope labeled reagent. Double bonds in molecules which are not conjugated during the reaction retain the originalcis configuration. The double bond in the Δ12 position is the most susceptible to positional isomerization to form the conjugated system. With the diene, this selectivity is small, while with the triene, the shifting of the Δ12 bond is the preponderant initial reaction. Isotopic experiments yielded direct evidence for the postulated carbanion mechanism of reaction. An activated methylene group is generally required for the formation of the carbanion. While the UV spectra of the reaction products formed from methyl linolenate at 140 C showed no peak in the diene region, 34% conjugated diene‐triene was present. The intact conjugated systems can migrate when the reaction is sufficiently energentic to produce conjugated trienes with double bonds other than the 10, 12, 14 system. The conjugation of triene is a stepwise reaction through the conjugated dienetriene.
The acyl and Alk‐1‐enyl groups of the major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions
Authors: Sun Grace Y. , Horrocks Lloyd A.
Published: November 2006

The major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions were separated by preparative thin layer chromatography. Alk‐1‐enyl groups from the alk‐1‐enyl acyl glycerophosphorylethanolamines were reacted with 1,3‐propanediol to form the 1,3‐dioxolane derivatives. Acyl groups were converted to the methyl ester derivatives and the acyl groups from alk‐1‐enyl acyl glycerophosphorylethanolamines and diacyl glycerophosphorylethanolamines were also determined separately. The acyl and alk‐1‐enyl group compositions of the phosphoglycerides from microsomal and mitochondrial fractions were quite similar. The ethanolamine and serine phosphoglycerides contained large amounts of 18∶0, 18∶1, 20∶4 and 22∶6 acyl groups. The choline phosphoglycerides had small amounts of polyunsaturated acyl groups and large amounts of 16∶0, 18∶1 and 18∶0 acyl groups. The mitochondrial cardiolipins contained unusual amounts of several acyl groups including 18∶1, 52%; 18∶2, 6%; and 16.1, 4%. A large portion of the mouse brain 18∶2 is in that fraction. The myelin phosphoglycerides were deficient in saturated and 22∶6 groups and markedly enriched in 18∶1 and 20∶1 groups when compared with the corresponding microsomal or mitochondrial phosphoglycerides.
Effect of ethanol on liver triglyceride concentration in fed and fasted rats
Authors: Johnson Owe
Published: November 2006

The effect of ethanol, given by gastric tube or by intraperitoneal injection, on the liver triglyceride concentration in fasted and ad libitum fed rats was investigated. Ethanol, independent of the route of administration, increased the liver triglyceride concentration in fasted rats during an 8 hr period but caused a much smaller increase in the ad libitum fed rats. The incorporation of intravenous injected3H‐oleic acid into the liver triglycerides increased significantly after ethanol feeding in fasted but not in fed rats. Based upon this and the plasma free fatty acid concentrations, it is concluded that ethanol causes a marked increase in the utilization of plasma free fatty acids for synthesis of liver triglycerides in fasted but not in fed rats. It is suggested that this is part of the explanation for the different responses to ethanol of the liver triglyceride concentrations in fasted and fed rats.
Distribution and specific activities of RNAs in isolated adipose cells with relation to exogenous lipids
Authors: Launay M. , Raulin J.
Published: November 2006

Several observations suggested that the rate of adipose cell formation is influenced by the fatty acid composition of the dietary fat: morphological studies, counting of cells, nuclear and mitochondrial DNA specific activities (SA). Therefore adipose cell RNAs were fractionated in an attempt to localize the site of this increased activity. Weanling rats were fed a diet containing 20% of sunflower oil (SO) or lard (L) for 21 days and fasted for 18 hr. They were then injected with either (6‐14C) orotic acid or32P‐phosphate and killed 210 min or 18 hr later. The adipose cell ribosomal and nuclear RNAs were extracted and fractionated by ultracentrifugation in a sucrose gradient. Comparison of the SA of the fractions revealed that: (1) after 210 min of incorporation, ribosomal RNAs were more active in cells from rats fed SO; after 18 hr, nuclear RNAs of these cells were more active; (2) in each extract, 18S RNAs were always more active in SO than in L; (3) in the cells from the rats fed SO, at the nuclear level the synthesis of rapidly labeled heterodisperse RNAs seemed accelerated; at the ribosomal level they seemed to be utilized more rapidly. This is interpreted as indicative of stimulated enzymic induction.
The metabolism of neutral lipids in the spur dogfish,Squalus acanthias
Authors: Sargent J. R. , Gatten R. R. , McIntosh R.
Published: November 2006

Cell free studies have shown that liver and intestine are the major sites of synthesis of triacyl glycerols inSqualus acanthias. The liver and to a lesser extent the intestine and stomach are major sites of wax ester synthesis. Muscle does not synthesize either triacyl glycerols or wax esters significantly. In vivo studies have shown that intravenously injected (3H) fatty alcohol is massively oxidized to (3H) fatty acid, the bulk of which appears in muscle. Liver appears to export both free fatty acids and triacyl glycerols to serum and thence to muscle. Free fatty acids, triacyl glycerols, wax esters and cholesteryl esters are all turned over within 48 hr inSqualus serum. The turnover of triacyl glycerols greatly exceeds the turnover of alkyl diacyl glycerols.
Lipid metabolism ofAgaricus bisporus (lange) sing.: II. Biosynthesis of sporophore lipids
Authors: Holtz R. Barry , Schisler Lee C.
Published: November 2006

In vivo biosynthesis of lipids ofAgaicus bisporus, the cultivated mushroom, was studied by examining incorporation of uniformly labeled14C‐linoleic acid and14C‐acetic acid added as supplements to mushroom compost. Incorporation of14C from both substrates showed similar patterns. Lipids from sporophores were labeled proportionally to their mass with the exception of free sterol which was labeled to a greater proportion in relation to its mass. Quantitative analyses of free sterol was accomplished using pyruvyl chloride 2, 6 dinitrophenyl hydrazone derivatives. Qualitative analysis of free sterol components was made using mass spectrometry.
Autoxidation of fatty acid esters in the presence of a heavy metal catalyst “Salcomine” (Co[II]‐bissalicylalethylenedi‐imine): I. Effect of catalyst upon rate of consumption of oxygen and decomposition of hydroperoxide
Authors: Jarvi Pentti K.
Published: November 2006

The autoxidation of fatty acid esters in the presence of a heavy metal chelate, “Salcomine” (Co[II]‐bissalicylalethylenedi‐imine), has been studied. Both antioxidative and prooxidative effects have been observed. When the concentration of the catalyst is decreased or the temperature is increased, the induction period becomes shorter and under some conditions disappears. It was shown that the decomposition of hydroperoxides is affected by salcomine; a first order reaction is involved with Arrhenius parameters E=21,000 cal, and A=8.99×1010 sec−1. The solubility of oxygen in fatty acid esters above 30 C, with and without salcomine, is the same. Theoretical aspects of the reaction mechanism, that are consistent with the experimental results, are proposed.
Synthesis of prostaglandins (PGE, PGF, PGA and PGB) in human platelets
Authors: Srivastava K. C. , Clausen J.
Published: November 2006

Human blood platelets, which previously have been shown to possess the necessary enzymic system for the synthesis of prostaglandins E, are also able to synthesize other prostaglandins, namely PGF, PGA and PGB. The synthesis and degradation rate of the prostaglandins were studied by chase experiments. Their synthesis rate was ca. 0.025 nmol acetate incorporated into PGE1 (and E2) per 109 platelets, while their degradation rate per hour was ca. 13% (PGE) and 8% (PGF) of the initial amount.
Synthesis and biological characterization of 10, 11‐methylene‐9‐nonadecene; an analog of sterculic acid
Authors: Clark James R. , Kircher Henry W.
Published: November 2006

A method is presented for the preparation of 10, 11‐methylene‐9‐nonadecene, a structural analog of the biologically active 9, 10‐methylene‐9‐octadecene (sterculene). When tested for its ability to inhibit stearyl CoA desaturase in vivo, 10, 11‐methylene‐9‐nonadecene failed to alter the stearic‐oleic acid ratio in the yolks of eggs from hens that had been fed 75 mg per day for 8 days. The compound did not give the Halphen test nor react rapidly with silver nitrate or methyl mercaptan in alcohol.
A simplified gas chromatographic procedure for analysis of lipoxygenase reaction products
Authors: Angelo Allen J. ST. , Dupuy Harold P. , Ory Robert L.
Published: November 2006

A simple and very sensitive technique was devised to analyze lipoxygenase reaction products by direct gas chromatography. Results showed that peanut lipoxygenase oxidizes linoleic acid at the C‐13 position exclusively.
Effect of chronic ethanol administration on cholesterol and bile acid synthesis in vivo
Authors: Lakshman M. R. , Gupta Atam D. , Veech Richard L.
Published: November 2006

Chronic administration of ethanol failed to stimulate the hepatic rate of cholesterol synthesis in meal‐fed rats. In contrast, chronic ethanol feeding caused a 50% inhibition in the rate of incorporation of [4‐14C] cholesterol to bile acids in the bile‐duct cannulated rats. It is, therefore, suggested that the decreased rate of cholesterol degradation to bile acids may play an important role in ethanol‐induced accumulation of cholesterol in liver.
Lipid metabolism of the yellow clam,Mesodesma mactroides: 3‐Saturated fatty acids and acetate metabolism
Authors: de Moreno Julia E. A. , Moreno Victor J. , Brenner Rodolfo R.
Published: November 2006

The fate of labeled palmitate, stearate, and acetate administered to the yellow clam,Mesodesma mactroides, was investigated. 1‐14C palmitic and 1‐14C stearic acids were oxidized to CO2 to a limited extent. They were mainly incorporated in diacylglycerols and triacylglycerols and were converted to higher homologs. After administration, palmitic acid was converted to stearic and oleic acids, whereas administered stearic acid was converted to 18∶1, 18∶2, 20∶1, and 20∶2 acids. Labeled acetate was readily included by the clam in 12∶0, 14∶0, 14∶1, 15∶0, 16∶1, 16∶1, 16∶2, 18∶2, 18∶1, 18∶2, 20∶1, 20∶2, and 20∶3 acids.
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

Fatty 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

The 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

Boars 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

A 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

A 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

An 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

The 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

As 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

Distribution 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

An 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

Under 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

The 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

The 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

The 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

Pregnant 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

The 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

A 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

Synthetic 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

The 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

Four 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

A 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

Age‐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.
Simultaneous mass spectrometric measurement of prostaglandins E1 (PGE1) and PGE2 with a deuterated internal standard
Authors: Ferretti Aldo , Flanagan Vincent P.
Published: November 2006

The use of (3,3,4,4‐2H4)PGE2 as internal standard for the quantitative measurement of PGE1 by gas chromatography‐mass spectrometry is reported. A method for the simultaneous analysis of PGE1 and PGE2 is also described. The prostaglandins were analyzed by selected ion monitoring as the methyl ester‐trimethylsilyl ether (ME‐TMS) derivatives of PGB1 and PGB2, respectively. In all cases, a linear response over the range 1 to 70 ng (2.8 to 198 pmoles) was demonstrated. The use of this procedure is exemplified by its application to the PG analysis of sheep seminal vesicles.
The composition and metabolism of high density lipoprotein subfractions
Authors: Schaefer Ernst J. , Foster David M. , Jenkins Leslie L. , Lindgren Frank T. , Berman Mones , Levy Robert I. , Brewer H. Bryan
Published: November 2006

The composition and metabolism of high density lipoprotein (HDL) subfractions were investigated in seven nomal individuals. Mean HDL2 (d, 1.063–1.125 g/ml) composition (by weight) was 43% protein, 28% phospholipid, 23% cholesterol, and 6% triglyceride, and mean HDL3 (d, 1.125–1.21 g/ml) composition was 58% protein, 22% phospholipid, 14% cholesterol, and 5% triglyceride. The mean apoA‐I; apoA‐II weight ratio was 4.75 for HDL2 and 3.65 for HDL3.HDL2 protein was proportionally slightly richer in C apolipoproteins and higher molecular weight constituents (including apoE) than HDL3. Kinetic studies utilizing radiolabeled HDLA (d, 1.09–1.21 g/ml), HDL2, and HDL3 demonstrated rapid exchange of apoA‐I and apoA‐II radioactivity among HDL subfractions, similar fractional rates of catabolism of apoA‐I and apoA‐II within HDL, and similar radioactivity decay within HDL subfractions. Mean plasma residence time was 5.74 days for radiolabeled HDL2 and 5.70 days for radiolabeled HDL3. Differences in HDL protein mass among individuals were largely due to alterations in catabolism, and in general both HDL2 and HDL3 were catabolized via a plasma and a nonplasma pathway. Data from simultaneous radiolabeled very low density lipoprotein and HDL studies in 2 individuals are consistent with the concept that apoC‐II and apoC‐III are catabolized at a different rate than are apoA‐I and apoA‐II within the HDL density range.
Cross‐linking of collagen in the presence of oxidizing lipid
Authors: Sundholm F. , Visapää A. , Björksten J.
Published: November 2006

Gelatin films containing unsaturated lipid have been exposed to ultraviolet and visible irradiation. No sign of paramagnetism could be detected in the films, although the gelatin was undergoing cross‐linking reactions. The addition of nitroxyl‐forming radical scavengers decreased the rate of cross‐linking, as did addition of ascorbic acid to the reacting mixture. Nitroxyls could not be detected in the gels, however. The conclusion is drawn that the main reaction in the cross‐linking reaction of collagen is a condensation of amino groups and extrinsic or intrinsic carbonyl groups. The extrinsic aldehydes are formed in the autoxidation of unsaturated lipid.
Arachidonic acid intestinal absorption: Mechanism of transport and influence of luminal factors on absorption in vitro
Authors: Chow San Laung , Hollander Daniel
Published: November 2006

The mechanism and characteristics of intestinal absorption of arachidonic acid were studied in vitro using everted intestinal sacs of the rat. Arachidonic acid absorption was studied at concentrations of 5 μM to 8.36 mM. The plot of absorption rate vs. concentration fitted best to a rectangular hyperbola at low μM concentrations and to a straight linear relationship in the mM range of concentrations. Metabolic inhibitors and uncouplers did not change absorption in either range of concentrations. The absorption of arachidonic acid increased with thinning of the unstirred water‐layer, decrease in the pH, or the substitution of sodium taurocholate by Pluronic F 68 or Tween 80. Absorption decreased following the equimolar additions of oleic, linoleic, and linolenic acids. Absorption rate did not change when the taurocholate concentration was varied from 5–15 mM or following the additions of butyric or glutamic acids, leucine, lysine, or dextrose. It was concluded that arachidonic acid is absorbed by a concentration‐dependent dual mechanism of transport which is not energy dependent. At the low μM range of concentrations, facilitated diffusion is predominant, while at mM concentrations, simple diffusion is the dominant mechanism of absorption. Changes in the intestinal fluid composition, flow rate, and pH can modify the rate of absorption of arachidonic acid.
The behavior of rat bile phospholipids in the intestine and in incubation media containing pancreatic juice
Authors: Boucrot P. , Reisser D. , Clement J.
Published: November 2006

Samples of radioactive bile were collected from rats after intravenous injection of potassium soaps ([9–103H2] or [114C] oleate, [114C] linoleate or [9–103H2] palmitate). These radioactive acids were chosen because it is well established that, in natural phosphatidyl cholines, palmitic acid is located chiefly at the 1 position and linoleic and oleic acids at the 2 position. After incubation of bile with pancreatic juice, the labeling of unchanged biliary phospholipids was higher when native bile was labeled with oleic acid than with palmitic or linoleic acids. These data suggest that monounsaturated molecular species of biliary phospholipids are more resistant than the diunsaturated ones to in vitro hydrolysis by phospholipase A2. Ninety min after introduction of the radioactive bile into the upper part of the rat duodenum, high labeling of luminal phospholipids was observed regardless of the bile sample used, although labeling of free fatty acids was always low. The passage of intact biliary phospholipids through the intestinal epithelium is discussed.
15‐Methyl‐1,2‐hexadecanediol, a major constituent of hamster surface wax
Authors: Schmid Pathica C. , Wedmid Yuri , Schmid Harald H. O.
Published: November 2006

Long chain 1,2‐alkanediol diesters comprise about 15–20% of the acetone soluble skin surface wax of golden Syrian hamsters. The constituent 1,2‐alkanediols, obtained through acidic methanolysis, were fractionated by preparative gas liquid chromatography of their isopropylidene derivatives. The major component (57%) was identified by nuclear magnetic resonance and mass spectrometry as 15‐methyl‐1,2‐hexadecanediol.
Fatty acid and molecular species composition of rat brain phosphatidylcholine and‐ethanolamine from birth to weaning
Authors: Crawford C. G. , Wells M. A.
Published: November 2006

The fatty acid composition of diacyl phosphatidylcholine and phosphatidylethanolamine from the brain of rats 3, 6, 9, 12, 15, 18, and 21 days old were determined. In phosphatidylcholine, the relative amounts of stearic and oleic acid increased from 25% to 33% while the relative amounts of myristic, palmitic, and palmitoleic decreased from 65% to 50% during this time period. The same pattern was seen in phosphatidylethanolamine with stearic and oleic increasing from 38% to 49% and the shorter chain acids decreasing from 17% to 13%. The polyunsaturated fatty content of phosphatidylcholine was approximately 10% and increased slightly during the first 3 weeks, while the polyunsaturated content of phosphatidylethanolamine decreased from 44% to 37%. The molecular species composition of phosphatidylcholine and phosphatidylethanolamine was determined in brains of rats 3, 6, and 9 days old. The relative amounts of the molecular species remained nearly constant during this time period with phosphatidylcholine containing 35% saturated, 40% monoenoic, 6% dienoic, 11% tetraenoic, 2% pentaenoic, and 5% hexaenoic. Phosphatidylethanolamine contained 1% saturated, 8% monoenoic, 3% dienoic, 40% tetraenoic, 9% pentaenoic, and 37% hexaenoic species. Analysis of the fatty acid composition of the molecular species reveals that in phosphatidylcholine the polyunsaturated fatty acids 20∶4 and 22∶6 are predominately paired with 16∶0, while in the phosphatidylethanolamine these two unsaturated fatty acids are paired with 18∶0. Furthermore, dipalmitoyl phosphatidylcholine accounts for approximately 25% of the total molecular species of that lipid.
Cardiopathogenicity of soybean oil and tower rapessed oil triglycerides when fed to male rats
Authors: Kramer J. K. G. , Hulan H. W. , Corner A. H. , Thompson B. K. , Holfeld N. , Mills J. H. L.
Published: November 2006

The triglycerides of soybean oil were purified by molecular distillation and those of Tower rapeseed oil by molecular distillation and adsorption chromatography. The original oils and the purified triglycerides were incorporated in semisynthetic diets at 20% by weight and fed for 16 weeks to weanling male Sprague‐Dawley rats to compare the nutritional and pathological effects of the oils and their triglyceride fractions on rats. The study was carried out at two independent laboratories. No significant differences were observed between the results of the two establishments. The incidence of myocardial lesions was significantly higher in rats fed Tower rapeseed oil than in those fed soybean oil. Purification of the triglycerides by molecular distillation and adsorption chromatography appeared to have no major effect on the incidence of myocardial lesions. This supports our previous findings that the cardiopathogenicity of the test oils to rats resides in the triglycerides of these oils.