bluuebunny/crossref_metadata_2025_split huggingface dataset:
A mechanism for hormonal activation of lipolysis and respiration in free brown fat cells
Authors: Fain John N. , Reed Nora 
Published: November 2006

AbstractFree brown fat cells were obtained by digestion of minced brown adipose tissue with bacterial collagenase. Electron micrographs have shown many mitochondria with tightly packed cristae in free brown fat cells. Lipolysis was activated in free brown fat cells was lipolysis accompanied by a marked stimulation of respiration. Insulin inhibits the catecholamine‐induced respiration in the complete absence of glucose. Catecholamines, theophylline and dibutyryl 3′,5′‐AMP all appear to activate lipolysis and respiration by a process dependent upon energy derived from mitochondrial oxidative phosphorylation. Uncoupling agents such asm‐chlorocarbonyl cyanide phenylhydrazone stimulated respiration. The addition of oligomycin prior to that of catecholamine inhibited the increase in respiration to a much greater extent than if it was added after the catecholamine. The increase in respiration due to lipolytic agents appears to be the result of increased free fatty acid release mediated through activation of lipolysis by cyclic 3′,5′‐AMP, since the addition of octanoate or palmitate to brown fat cells mimicked the effects of lipolytic agents on respiration. The activation of energy metabolism may be the result of a large increase in the energy‐dependent cyclic transport of K+, as a result of alterations in the mitochondrial membrane by free fatty acids. This hypothesis is based on the following findings. The activation of respiration by fatty acids or lipolytic agents was dependent upon the presence of K+ in the medium. The addition of K+, Rb+ or Cs+, but not NH4+, to fat cells isolated and incubated in K+‐free buffer restored the ability of lipolytic agents to increase respiration. Valinomycin, an antibiotic which stimulates uptake of K+ by mitochondria and increases the permeability of lipid membranes to K+, was a potent stimulator of respiration in free brown fat cells in the presence of K+. The stimulation of respiration by theophylline or valinomycin was blocked by nigericin which also increases the K+ permeability of membranes but blocks the uptake of K+ by mitochondria. The lipolytic action of theophylline was virtually unaffected by K+ or nigericin.
Effects of insulin and norepinephrine added in vitro on the metabolism of brown adipose tissue in the absence of added glucose
Authors: Joel Cliffe D. 
Published: November 2006

AbstractRat interscapular brown adipose tissue slices incubated with succinate as substrate can be stimulated by norepinephrine to exhibit a rate of oxygen consumption that appears to exceed by a wide margin that reported for any other rat tissue under any conditions in vitro. This further supports the concept of brown adipose tissue as a specialized site of heat production. Brown adipose tissue slices under maximal stimulation by norepinephrine and incubated in the absence of added substrate consume oxygen linearly and at a high rate for at least 14 hr. This is taken as further evidence that stored lipid can act as the major fuel to support the vigorous oxidative metabolism of which this tissue is capable. This unusually stable preparation appears to be attractive as a system for the study of relatively long‐term effects of hormones in vitro. Brown resembles white adipose tissue in that insulin exerts an antilipolytic effect on both types of tissue in Krebs‐Ringer phosphate buffer in the absence of added glucose. On the other hand, insulin stimulates the oxygen consumption of brown but not white adipose tissue under these conditions. A procedure is described for the rapid and nearly quantitative removal of the interscapular brown adipose tissue from a rat, virtually free of contamination by muscle or white adipose tissue.
The composition and metabolism of developing brown and white fats
Authors: Smalley R. L. , Minor J. J. , Rowe L. 
Published: November 2006

AbstractThis investigation was concerned with analysis of the composition and metabolism of developing adipose tissues in the postnatal hamster. Particular attentions were given to the development of brown fat and the relationship of brown and white fats to each other. Correlations with previous histological studies are stressed. The parameters studied were water content, total lipid content, glycogen content, fatty acid compositions of total lipid extracts, malic dehydrogenase activity as assayed from oxaloacetate to malate, glucose‐6‐phosphate dehydrogenase activity and aldolase activity.
The composition of beeswax and other waxes secreted by insects
Authors: Tulloch A. P. 
Published: November 2006

AbstractThis review deals, with waxes of members of two quite different groups of insects, the bees and the scale insects, which secrete large amounts of wax. The former use was as a structural material and the latter as a protective material. The compositions of waxes from some of these insects are described and particular attention is paid to the compositions of the unhydrolyzed waxes and to the presence of hydroxy acids. New analyses of beeswax and of wax of a species of bumble bee are reported. The structures of the diesters, hydroxyesters and diols of beeswax are elucidated. The bumble bee wax contains major proportions of saturated and unsaturated hydrocarbons, and of long chain saturated, mono‐ and diunsaturated esters. The relationship between structure and function of the waxes is discussed.
Fatty acids of the alkane diol diesters of vernix caseosa
Authors: Ansari M. N. A. , Fu H. C. , Nicolaides N. 
Published: November 2006

AbstractThe fatty acid monoenes esterified to the alkane diol diesters of vernix caseosa lipid form two patterns of homologues starting from either C16Δ9 or C16Δ6 and adding (or subtracting) an integral number of C2 units at the carboxyl group. Although components of the Δ6 pattern are the predominant monoenes of sebaceous gland ester lipid classes, for these diol diesters Δ9 pattern components are preferentially used.
Sterol galactosides and sterol esters of the cotton bud
Authors: Thompson A. C. , Henson R. D. , Gueldner R. C. , Hedin P. A. 
Published: November 2006

AbstractAbout 60% of the total sterols in the cotton bud appeared in the free state; the esterified sterol glycosides contained about 50% saturated fatty acids, largely palmitic acid; the principal unsaturated fatty acid was linolenic acid. β‐Sitosterol was the major sterol in all classes of sterol derivatives. The sugar moiety of the esterified sterol glycosides and the sterol glycoside was galactose. Efforts are continuing to evaluate the minor sterols of cotton buds, some of which appear to be hydroxylated ecdysones, and to study their relationship to the development of the Boll weevil,Anthonomus grandis Boheman.
The GLC and TLC resolution of diastereoisomeric polyhydroxystearates and assignment of configurations
Authors: Wood Randall , Bever E. L. , Snyder Fred 
Published: November 2006

AbstractTrifluoroacetate (TFA) derivatives of methyl 12‐hydroxystearate, methyl ricinoleate, five positional isomers of methylthreo‐ anderythro‐dihydroxystearate, four diastereoisomeric methyl 9,10–12‐trihydroxystearates, and four racemic diastereoisomeric methyl 9,10–12,13‐tetrahydroxystearates were prepared and analyzed by gas‐liquid chromatography (GLC). The isomericthreo‐ anderythro‐dihydroxystearates that had not previously been resolved by GLC were separated. Excellent resolution of the diastereoisomeric pairs of methylthreo‐ anderythro‐9,10–12‐triand and methylerythro, erythro‐ andthreo, threo‐9,10–12,13‐tetrahydroxystearates was obtained by GLC of their TFA derivatives. Analyses of these high‐molecular‐weight compounds were carried out on polar and nonpolar packed columns used routinely for methyl ester analysis.The various methyl mono‐, di‐, tri‐, and tetrahydroxysterate esters were also analyzed by thin‐layer chromatography (TLC) on Silica Gel G adsorbent layers and on Silica Gel G impregnated with sodium arsenite.Relative and absolute configurations were assigned to the various diastereoisomeric tri‐ and tetrahydroxysterates based on information obtained from GLC, TLC, synthetic ratios, and molecular‐models.A micro hydroxylation method that gives quantitative yields ofthreo‐ anderythro‐dihydroxy acids from various concentrations of C18 monoene geometrical isomers was developed. Subsequent GLC analysis of the isomeric methyl dihydroxy TFA derivatives allows the quantitative determination of double‐bond configuration on small samples without expensive or specialized equipment.
Synthesis of cholesterol and total lipid by male and female rats fed beef tallow or corn oil
Authors: Dupont Jacqueline 
Published: November 2006

AbstractMale and female weanling rats were fed diets containing 2 or 42% of calories as corn oil or 40% as beef tallow plus 2% as corn oil until they were 12 or 18 weeks of age. Incorporation of C14‐acetate into lipids of serum and liver and concentration of lipids in serum, liver, and carcass at the end of these periods were determined.Net synthesis of noncholesterol lipid was repressed by changing the diet from 2% to 42% of calories from either dietary fat in both sexes and at both ages. Cholesterol net synthesis was enhanced 29‐fold in males and 22‐fold in females fed 42% corn oil compared to 2% corn oil to the age of 12 weeks. It was enhanced only 2.6‐fold for males and 3.4‐fold for females by 40% beef tallow plus 2% corn oil. At 18 weeks of age cholesterol synthesis in males fed 42% corn oil was 7.3 and in females 9.1 times the value for those fed 2% corn oil. At this age the values for rats fed 40% beef tallow plus 2% corn oil were 1.2 and 3.7 times those for 2% corn oil fed rats of the respective sexes.
Fatty acid oxidation in relation to cholesterol biosynthesis in rats
Authors: Dupont Jacqueline 
Published: November 2006

AbstractGroups of male and female rats were fed diets containing (calorie basis) 2% corn oil (low‐fat, LF), 42% corn oil (CO) or 2% corn oil plus 40% beef tallow (BT) for 2 weeks. Then rats of each sex and diet group were given an intraperitoneal injection of14C‐acetate,‐ stearate‐ oleate or linoleate. Acetate incorporation into cholesterol and rate of oxidation of each fatty acid were determined. Specific activity of cholesterol was higher in females than males, higher with 40% lipid in the diet than with 2% corn oil and higher for CO than BT. Linoleate was oxidized more rapidly than oleate which exceeded stearate. An index of dietary lipid oxidation was computed based on fatty acid oxidation rate, per cent of each fatty acid in the diet and per cent of lipid calories in the diet. Serum cholesterol‐14C was found to be proportional to dietary lipid oxidation index.
Thin‐layer chromatographic separation of dimethylphosphatidates derived from lecithins
Authors: Wurster C. F. , Copenhaver J. H. 
Published: November 2006

AbstractThe separation of lecithin derivatives based on their fatty acid substituents has been investigated. Several synthetic and natural lecithins were converted to their corresponding dimethylphosphatidates by hydrolysis with phospholipase D (phosphatidylcholine phospholipase D (phosphatidylcholine phosphatidohydrolase, EC 3.1.4.4) and methylation of the resulting phosphatidic acids with diazomethane. These dimethylphosphatidates were separated into fractions by reversed‐phase thin‐layer chromatography. Separations were dependent on the total number of methylene groups and double bonds in the two fatty acid chains. Fractionated dimethylphosphatidates were extracted from the plates and fatty acids were determined.
The total synthesis of dilinoleoylphosphatidylserine and its activity in blood clotting systems
Authors: Turner D. L. , Silver M. J. , Baczynski E. 
Published: November 2006

AbstractA total synthesis ofdl‐phosphatidyl‐(dilinoleoyl)‐l‐serine was achieved by the acylation of the barium salt of the phthalimidomethyl ester of glycerophosphoryl‐n‐anisyloxycarbonyl‐l‐serine. The dilinoleoyl intermediate was treated with hydrazine to remove the phthalimidomethyl group and with hydrogen chloride to remove the anisyloxycarbonyl protecting group. The resulting phosphatidylserine was purified by Rouser's methods, solubilized, and tested for biological activity in the antithromboplastin, recalcification, and Hicks‐Pitney tests. It was found to have about the same anticoagulant activity as beef brain phosphatidylserine and hence was more active than the less unsaturated phosphatidylserine synthesized earlier.
Quantitative and qualitative analyses of isolated lipid droplets from interstitial cells in renal papillae from various species
Authors: Bojesen Inge 
Published: November 2006

AbstractThe lipid droplets of renal papillae homogenates from four different species were obtained by ultracentrifugation. Ca. 80–98% of the lipids (triglycerides, phospholipids, free fatty acids, and cholesterol esters) consist of triglycerides. The triglycerides were fractionated by argentation thin layer chromatography and each fraction characterized by gas liquid chromatography. No fraction contained any unique triglyceride. The fatty acid composition of the total triglycerides, as analyzed by gas liquid chromatography and ozonolysis, differed markedly from the fatty acid composition of the corresponding plasma triglycerides. The papillary triglycerides were characterized by higher concentrations of stearic acid, arachidic acid, and polyunsaturated acids with 20 or more carbon atoms. Particularly interesting was the presence in the lipid droplets of docosa‐7,10,13,16‐tetraenoic acid. This acid has been shown to be a major component in the cholesterol ester fraction of rat and canine adrenal lipids. In the papillary triglycerides, this acid accounted for 7%, 15%, and more than 20% of the total fatty acids in the dog, rat, and rabbit, respectively. The pig differs from these three species in having only ca. 1% of this acid. These observations suggest that the interstitial cells produce these triglycerides. This production could occur either by a transacylation from phospholipids and cholesterol esters and by a de novo synthesis from locally produced fatty acids. The possibility that the triglyceride production may be involved in a control of the prostaglandin production of the renal medulla is discussed.
Changes in in vivo metabolism of bile acids in rat after treatment with phenobarbital
Authors: Cronholm Tomas , Einarsson Kurt , Gustafsson Jan‐Åke 
Published: November 2006

AbstractThe influence of phenobarbital on pool size and turnover of bile acids in rats have been investigated by administration of [24‐14C] cholic acid and tritium labeled chenodeoxycholic acid. Phenobarbital treated rats had a smaller cholic acid pool compared to control rats (6.08±2.09 mg and 23.60±7.66 mg, respectively). The pool size of chenodeoxycholic acid, plus its metabolites (α‐ and β‐muricholic acids), was of the same magnitude in the two groups of animals. Also the daily production of cholic acid was decreased in phenobarbital treated rats compared to control rats (2.12±0.46 mg and 7.24±1.66 mg, respectively). No significant difference was observed between the synthesis of chenodeoxycholic acid in the two groups of animals.
Simplified procedure for preparation of35S‐labeled brain sulfatide
Authors: Fluharty Arvan L. , Davis Marsha L. , Kihara Hayato , Kritchevsky Gene 
Published: November 2006

AbstractA simplified procedure for the preparation of35S‐labeled brain cerebroside sulfates has been developed. The labeled sulfatides are synthesized in vivo after intracerebral administration of inorganic35S‐sulfate in developing rats. The animals are sacrificed three days later and brain homogenates extracted with chloroform‐methanol. The extract is subjected to mild alkaline treatment and washed with water. The organic phase is chromatographed on triethylaminoethyl‐cellulose from which sulfatides are eluted with chloroform‐methanol containing potassium acetate. Radioactive fractions are pooled, concentrated, and potassium acetate removed by dialysis against water. Alternatively, salts are removed by passing radioactive fractions through Sephadex G‐25. After evaporating to near dryness, the radioactive cerebroside sulfates are dissolved in a small volume of chloroform‐methanol and stored at −20 C. The35S‐sulfatides are essentially free of lipid contaminants, and 97% of the radio‐activity corresponds with sulfatides on chromatographic analysis.
Lipid composition of normal and hypertrophic bovine thyroids
Authors: Lagrou A. , Dierick W. , Christophe A. , Verdonk G. 
Published: November 2006

AbstractThe phospholipid content of bovine thyroid tissue amounts to 70% of total lipid. Triglycerides and cholesterol are the main neutral lipids. Only trace amounts of free fatty acid and esterified cholesterol are found, while two not yet identified components also are present. The distribution of lipid phosphorus in the different phospholipid classes is as follows: phosphatidyl choline, 43.0%; phosphatidyl ethanolamine, 25.2%; phosphatidyl serine, 5.6%; phosphatidyl inositol, 6.5%; sphingomyelin, 14.0%; cardiolipin, 2.8%; lysophosphatidyl choline, <1%; and phosphatidic acid, <1%. The phosphatidyl ethanolamines are rich in plasmalogens. The fatty acid patterns in the different lipid classes are reported. The essential differences between normal and hypertrophic bovine thyroid tissue are higher water content and lower triglyceride and sphingomyelin values for hypertrophic tissue.
Biosynthesis of triglycerides in freshly secreted milk from goats
Authors: Christie W. W. 
Published: November 2006

AbstractIt has been confirmed that freshly secreted milk from goats contains triglyceride synthetase activity which is not stimulated by addition of the usual range of cofactors, e.g. coenzyme A, adenosine 5′‐triphosphate, Magnesium ions or α‐glycerophosphate. On the other hand, free glycerol did stimulate the reaction, although only low levels of glycerol‐kinase could be detected. The products were principally, triglycerides, diglycerides, and phosphatidic acid, i.e. those expected of the phosphatidic acid pathway of triglyceride biosynthesis together with some phosphatidyl choline and phosphatidyl ethanolamine. In addition, some of the enzymes of the monoglyceride pathway appeared to be present since 2‐O‐alkylglycerols, in particular, were converted to monoacyl‐monoalkyl glycerols together with trace amounts of diacyl alkyl‐glycerols. The milk incorporated a wide variety of isotopically labeled fatty acids into lipids at widely differing rates (18∶2 at 10 times the rate of 18∶0, for example) and stereospecific analysis confirmed that fatty acids entered all three positions of the sn‐triacyl glycerols according to quite specific patterns. Stearic acid was desaturated rapidly to oleic acid, and virtually all the 18∶1 formed was esterified (to all three positions in the triglycerides also). Freshly secreted milk is a potentially useful alternative to tissue obtained surgically as a source of mammary triglyceride biosynthetic enzymes for the study of milk fat biosynthesis in vitro.
Lipid changes during life cycle of marine copepod,Euchaeta japonica marukawa
Authors: Lee Richard F. , Nevenzel Judd C. , Lewis A. G. 
Published: November 2006

AbstractAll stages from egg to adult of the North Pacific copepod,Euchaeta japonica contained wax esters in their lipid stores, while triglycerides were important only in the eggs, early naupliar stages, and adults. The large lipid reserves of the eggs were wax esters and triglycerides (58% and 19% of the lipid, respectively), both of which were used rapidly during the early stages of development. Wax esters continued to decrease after triglycerides had been utilized completely for energy. The slow metabolism of lipid during starvation indicated that lipid stores in adult females may be conserved for egg production. The dominant alcohols of the wax esters of all stages were tetradecanol (24–42% of the total) and hexadecanol (25–65%). Only minor amounts of polyunsaturated alcohols were observed. There was, however, a high proportion of polyunsaturation in the wax ester fatty acids, even though octadecenoic was generally predominant (16–46% of the total wax ester fatty acids). The polyunsaturation of the wax esters fatty acids and the presence of 21∶6 hydrocarbon suggest phytoplankton in the diet of adults and in the younger stages. Cholesterol was the main sterol, but there were minor amounts of desmosterol (1–12% of the total sterols) present. The latter sterol has not been found previously in copepods, although reported from Cirripedia and Decapoda.
Lipid peroxidation in chronic ethanol treated rats: In vitro uncoupling of peroxidation from reduced nicotine adenosine dinucleotide phosphate oxidation
Authors: Koes Mary , Ward Tom , Pennington Sam 
Published: November 2006

AbstractChronic ethanol treated rats were found to have enhanced ethanol metabolism and to metabolize ethanol in vivo in the presence of an inhibitor of alcohol dehydrogenase. In vitro studies of the hepatic microsomal system thought to the responsible for this activity showed it to be markedly induced. Lipid peroxidation also was enhanced in the ethanol treated animals. The lipid peroxidation was shown to be uncoupled from the microsomal nicotinamide adenine dinucleotide phosphate, reduced form, oxidase activity by a low concentration of azide.
Properties of palmityl‐CoA: L‐α‐glycerolphosphate acyl transferase from bovine mammary microsomes
Authors: Gross M. J. , Kinsella J. E. 
Published: November 2006

AbstractPalmityl‐coenzyme A: L‐α‐glycerolphosphate acyltransferase is the most active acyltransferase of bovine mammary microsomes, with a specific activity ranging from 8–20 nmoles min−1 mg−1 protein. Corresponding acylation rates of 2.2, 1.4, 2.1, and 0.6 nmoles min−1 mg−1 were obtained for myristyl‐, stearyl‐, oleyl‐ and linoleyl‐coenzyme A, respectively. Optimum pH of palmityltransferase was 7.7, and activity was not affected by buffer molarity in range 25–150 mM. Inhibitory effects of palmityl‐coenzyme A (10 μM/0.1 mg microsomal protein) was relieved by bovine serum albumin. Sonication magnesium and ethylenediaminetetraacetic acid enhanced activity. Delipidation of microsomes reduced activity by 84%; restoration of extracted lipids achieved 70% of original activity. Apparent Km and Vmax values of 4.1 and 260 μM and 9.5 and 8.2 nmole min−1 mg−1 were determined for palmityl‐coenzyme A and D,L‐α‐glycerolphosphate, respectively, using untreated microsomes. The enzyme was stable as lyophilized microsomes when stored at −30 C. Phosphatidic acid was the major product and marked quantities of diglycerides were formed, especially when microsomal protein was increased.
Complex formation and reversible oxygenation of free fatty acids
Authors: Campbell I. M. , Caton R. B. , Crozier D. N. 
Published: November 2006

AbstractCombined manometric and spectrophotometric studies reveal that prior to true oxidation unsaturated fatty acids undergo an oxygenation which is reversible in response to changes in oxygen pressure. The oxygenation seems to result from the oxygen molecule having a specific affinity for pairs of olefinic bonds.
Composition ofCelastrus orbiculatus seed oil
Authors: Miller Roger W. , Smith C. R. , Weisleder D. , Kleiman R. , Rohwedder W. K. 
Published: November 2006

AbstractThe seed oil ofCelastrus orbiculatus (family Celastraceae) was reinvestigated to determine whether the benzoic acid that it contains is esterified with glycerol. Unlike acetic acid, benzoic acid is not incorporated in glycerides of this oil but, instead, is esterified with two sesquiterpenoid triols of the empirical formula C15H26O4.trans‐Cinnamic acid also is esterified with these triols. Acetic acid is a component of these nonglyceride esters, as well as of the triglycerides. We found no evidence for the occurrence of formic acid in this oil. By countercurrent fractionation, we found that this oil contains 8% “ordinary” triglycerides, 59% mono‐acetotriglycerides, and 33% nonglyceride substances.