bluuebunny/crossref_metadata_2025 huggingface dataset:
Substrate metabolism in the perfused lung: Response to changes in circulating glucose and palmitate levels
Authors: Shaw Mary E. , Rhoades Rodney A.
Published: November 2006

The effects of circulating levels of glucose and palmitate in the isolated perfused rat lung were investigated. Rat lungs were perfused for 1.5 hr with washed bovine erythrocytes (15% hematocrit) in Krebs‐Henseleit bicarbonate buffer containing 5 g% bovine serum albumin. Glucose uptake in the perfused lung varied directly with circulating glucose concentration. Lactate production was affected proportionately more by high glucose levels than by low concentrations. Pyruvate production was decreased by both low glucose and palmitate concentration in the circulating medium. Oxidation of glucose to CO2 was depressed by low glucose and by high palmitate concentrations. Glucose incorporation into lung lipids was more strongly influenced by glucose concentration than by circulating palmitate levels. These data indicate acute changes in circulating levels of glucose and palmitate alone can act to either inhibit or stimulate glycolysis, glucose oxidation, and lipid synthesis in the perfused lung.
Positional distribution of fatty acids in the triglycerides of bovine milk fat with elevated levels of linoleic acid
Authors: Morrison I. M. , Hawke J. C.
Published: November 2006

A stereospecific distribution of fatty acids in bovine milk fat containing 15.5% linoleic acid has been compared with the distribution in bovine milk fat containing a normal level (1.8%) of linoleic acid. The positional distribution was obtained by the separate analysis of milk fat triglycerides of high, medium, and low molecular weight. The order of preference for linoleic acid in the high molecular weight triglycerides was position 3>position 2 >position 1. There was an accompanying altered distribution of myristic acid and palmitic acid in favor of position 1 at the expense of position 3. However, the proportions of myristic acid and palmitic acid in position 2, relative to positions 1 and 3 were identifical in the high molecular weight fractions of the two milk fats. The distribution of linoleic acid in the medium molecular weight triglycrides of linoleic‐rich milk fat was position 1=position 2>position 3. This resulted in a change in the distribution of 18 carbon monounsaturated fatty acids in favor of position 2 at the expense of position 1, but the distribution of myristic acid and palmitic acid was virtually unaltered. The distribution of linoleic acid in the low molecular weight triglycerides was position 2>position 1>position 3. The amounts of myristic acid and palmitic acid in position 2 and of palmitic acid in position 1 decreased in the low molecular weight triglycerides of the milk fat containing elevated levels of linoleic acid. Changes in the distribution of fatty acids which were observed in the separate analysis of the high, medium, and low molecular weight triglycerides were not apparent when comparing the distribution in the total milk fats. For example, the distribution of myristic acid and palmitic acid appeared to be unchanged, while the distribution of 18 carbon monounsaturated fatty acids was slightly altered in favor of positions 2 and 3. Moreover, linoleic acid showed an almost equal preference for the three positions of the glycerol moiety in milk fat containing elevated levels of this fatty acid with some concentration at position 2.
The dietary regulation of stearyl coenzyme A desaturase activity and membrane fluidity in the rat aorta
Authors: Holloway Caroline T. , Holloway P. W.
Published: November 2006

Numerous studies have demonstrated that alterations in membrane composition or fluidity are often associated with alterations in the properties of membrane‐bound enzymes. In order to obtain membranes of varying fluidity, rats were fed diets that were either fat‐free or supplemented with 15% safflower oil, and two properties associated with aorta and liver microsomal membranes were selected for study: stearyl CoA desaturase activity, and fluidity as monitored by fatty acid composition and microviscosity (measured by fluorescence depolarization). If fluidity directly modulates desaturase activity, one would predict that a low fluidity would stimulate the desaturase activity. Ten times more desaturase activity is present in aorta microsomes from rats on a fat‐free diet than in microsomes from rats on a safflower oil supplemented diet. However, on the fat‐free diet, these aorta microsomes were more fluid than those of rats fed safflower oil supplemented diet. The fluidity of liver microsomal membranes was not altered in response to diet, despite significant changes in desaturase enzyme content. The contrasting evidence presented here suggests that no correlation exists between desaturase enzyme activity and membrane fluidity in the two tissues studies. We have demonstrated that the aorta has appreciable capacity to desaturate stearyl CoA and that dietary manipulation causes significant changes in aorta membrane fluidity that may be of sufficient magnitude to affect the overall metabolism of aorta cells.
Analysis of autoxidized fats by gas chromatography‐mass spectrometry: III. Methyl linolenate
Authors: Frankel E. N. , Neff W. E. , Rohwedder W. K. , Khambay B. P. S. , Garwood R. F. , Weedon B. C. L.
Published: November 2006

The gas chromatography‐mass spectrometry (GC‐MS) method developed in the preceding papers was extended to the analysis of autoxidation products of methyl linolenate. Four isomeric hydroxy allylic trienes with a conjugated diene system were identified after reduction of the linolenate hydroperoxides. All eight geometrictrans,cis‐ andtrans, trans‐conjugated diene isomers of these hydroxy allylic compounds were identified and partially separated by GC of the trimethylsilyl (TMS) ether derivatives. The proportion found of 9‐ and 16‐hydroperoxides was significantly higher (75–81%) than the 12‐ and 13‐hydroperoxides (18–25%). The tendency of the 12‐ and 13‐hydroperoxides to form cyclic peroxides, cyclic peroxidehydroperoxides, and prostaglandin‐like endoperoxides was supported by indirect evidence for the presence of 9,10,12‐ and 13,15,16‐trihydroxyoctadecanoate in hydrogenated derivatives of the highly oxygenated products. The quantitative GC‐MS method was used to determine the relative contribution of linolenate, linoleate, and oleate in mixtures to the formation of hydroperoxides.
Lipids of cultured hepatoma cells: VIII. Utilization of D‐[1‐14C] glucose for lipid biosynthesis
Authors: Welch Charles L. , Wood Randall
Published: November 2006

Minimal deviation hepatoma 7288C cells (HTC) were incubated in serum‐supplemented and serum‐free Swim's 77 medium in the presence of D‐[1‐14C] glucose for 1, 2, 4, 8, 12 and 24 hr. Glucose oxidation to CO2, incorporation into total cell mass, and incorporation into cell and medium lipids were determined. The percentage distribution of total cell lipid radioactivity in individual neutral and polar lipid classes was followed as a function of time. Degradation studies of individual lipid classes were performed to ascertain the percentage of radioactivity in acyl and glycerol moieties. The percentage of D‐[1‐14C] glucose oxidized to14CO2, incorporated into cell matter and cell lipids was elevated in cells incubated in serum‐free medium as opposed to serum‐supplemented medium. The percentage distribution of total cell lipid radioactivity into individual neutral lipid classes from both serum‐free and serum‐supplemented cultures was as follows: sterols > triglycerides > free fatty acids > sterol esters. The percentage distribution of total cell lipid radioactivity into individual polar lipid classes of serum‐supplemented cultures was as follows: phosphatidylcholine > phosphatidylinositol > sphingomyelin > phosphatidylethanolamine > phosphatidylserine. The distribution of glucose radiolabel into individual polar lipid classes of serum‐free HTC cells was different from their serum‐supplemented counterparts: sphingomyelin > phosphatidylcholine > phosphatidylinositol > phosphatidylethanolamine > phosphatidylserine. Glycerol from glyceride classes contained a higher percentage of radioactivity than the acyl moieties, with this percentage significantly elevated in serum‐free cultures. The data indicate that, although glucose is a substrate for HTC cell lipids, other precursors present in the culture system also contribute to the lipid constituency of this hepatoma cell line.
The effect of a short term saturated fat diet on the apoprotein composition and radioiodination properties of rat very low density lipoproteins
Authors: Poulis Parissa , Fidge Noel H.
Published: November 2006

The effect of a saturated fat diet on the apoprotein composition and radioiodination properties of plasma very low density lipoprotein (VLDL) was studied in rats. After feeding the diet for 10 days, the proportion of125I attached to VLDL lipid decreased from 50% (control animals) to 8%, the remainder (92%) being bound to the apoportein components. The decreased lipid labelling was associated with proportional changes in the fatty acid composition of serum and VLDL lipids, the most notable change being a reduction in linoleic acid (30–8%) content which occurred in all the major lipid classes of both serum and VLDL. Analysis of VLDL after radioiodination showed that most of the radioactivity incorporated into the lipid moiety was associated with phospholipid. The proportion of125I bound to phospholipid decreased after feeding rats a saturated diet. The proportion of soluble (small molecular weight peptides and arginine rich peptide) to insoluble (B apoprotein) did not alter during the saturated fatty acid dietary regime and no differences in the distribution of soluble proteins were observed. It is concluded that feeding a saturated fat diet to rats for 10 days significantly improved125I labelling of the apoprotein moiety while apparently not inducing changes in apoprotein composition.
Synthesis of a monobrominated analog of dipalmitoyl lecithin
Authors: Reinert J. C. , Lowry R. R. , Wickman H. H.
Published: November 2006

The synthesis of 1‐palmitoyl‐2‐monobromopalmitoyl lecithin, where the β‐chain is brominated in either the 9‐ or 10‐position, is reported, Monobromopalmitic acid was prepared by addition of HBr to palmitoleic acid, and the anhydride of the fatty acid conjugated with 1‐palmitoyl lysolecithin. The resulting lecithin was isolated by preparative thin layer chromatography and its structure confirmed by chemical and enzymatic analysis.
Diester waxes from skin lipids of the feet of biotin depleted and biotin supplemented Turkey poults
Authors: Logani Mahendra K. , Nhari David B. , Forbes P. Donald , Davies Ronald E.
Published: November 2006

The neutral lipids of the skin from the feet of turkey poults fed a biotin supplemented or a biotin deficient diet consist mainly of triacylglycerols, and of mono‐ and diester waxes. Diester waxes from both groups were characterized as fatty acid esters oferythro‐2,3‐alkanediols. A comparison between fatty acid composition of the two groups, however, revealed the following significant differences. Biotin deficient birds showed a fairly high concentration of very long chain fatty acids (C36–C40) which were completely absent in biotin supplemented birds. Further, almost one‐third of the fatty acids of diester waxes in biotin deficient birds were unsaturated while those from biotin supplemented birds were predominantly (96%) saturated.
Equilibrium of taurodeoxycholate between mixed micellar and aqueous phases: Effect of amphiphile
Authors: Borgström B.
Published: November 2006

The equilibration of taurodeoxycholate between mixed micellar and aqueous phases has been studied by equilibrium dialysis. The presence of amphiphiles in the form of lecithin, long chain monoglyceride, and fatty acid in the bile salt solution will greatly decrease the bile salt concentration in the aqueous (intermicellar) phase. At high amphiphile concentration relative to bile salt, the concentration of bile salt in the aqueous phase will be below the critical micellar concentration (CMC) of the pure bile salt solution. Under these conditions, few simple micelles will be present and no binding of bile salts to protein takes place as indicated by experiments with colipase. The lowering of the concentration of bile salt in the aqueous phase by the presence of amphiphile may be a physiological mechanism to regulate bile salt absorption during the digestive phase of fat absorption.
Protective effect of biliary lipids on rat pancreatic lipase and colipase
Authors: Lairon D. , Nalbone G. , Lafont H. , Domingo N. , Hauton J. C.
Published: November 2006

The effect of biliary components on the inactivation of rat pancreatic lipase and colipase was studied. In vitro incubations of these proteins were performed at 37 C in the presence or absence of trypsin, under various conditions. The influences of bile lipoprotein complex, bile salts below or above the critical micellar concentration (CMC), or albumin were investigated. The results showed that albumin and bile salts below the CMC had no protective effect on the inactivation rate of lipase or colipase. Under both denaturating conditions, bile salts above the CMC had a very slight effect, whereas the presence of the bile lipoprotein complex maintained lipase and colipase activity. The magnitude of this effect was related to the biliary phospholipid concentration. By means of gel filtration, the protective effect of bile was found to be due to associations of bile lipoprotein complex with these proteins in presence of bile salts. A correlation between the amount of colipase and the protection of lipase in the presence of biliary phospholipids was observed. Intestinal content of rats with normal and diverted bile secretion was submitted to the same in vitro incubation, and the enzyme was more stable in the segments containing biliary phospholipids. This suggests that the interaction between the bile lipoprotein complex, colipase and lipase in the presence of bile salts could have an important role in the intestinal lumen by retaining the enzyme activity.
Lipid accumulation in cells derived from porcine aorta and grown under anaerobic conditions
Authors: Briggs Robert G. , Glenn Joseph L.
Published: November 2006

Fibroblast‐like cells, derived from porcine aorta, were cultured under aerobic and anaerobic conditions. Light and electron microscopic examinations, lipid composition measurements, and incorporation of radioactive precursors into lipids of these cells were performed. Anaerobically grown cells accumulated oil red 0 stainable droplets and within 6 hr the triacylglycerol content increased to 4 times the level determined in cells grown under aerobic conditions. This ratio remained constant throughout an additional 12 hr of growth. The fatty acid composition of the triacylglycerols which accumulated under anaerobic conditions differed from the composition of fatty acids in the triacylglycerols present in the growth medium. The cellular unesterified fatty acids of the anaerobically grown cells differed only slightly in composition from the fatty acids in the growth medium, while the unesterified fatty acids of aerobically grown cells differed to a greater extent from those of the growth medium.
Fatty acid metabolism in the calanoid copepodParacalanus parvus: 1. Polyunsaturated fatty acids
Authors: Moreno Victor J. , De Moreno Julia E. A. , Brenner Rodolfo R.
Published: November 2006

The metabolic fate of radioactive linoleate and α‐linolenate administered to the South Atlantic copepodParacalanus parvus was studied. The wild copepod was able to incorporate the labeled acids dissolved in seawater. The radioactive linoleate was elongated to 20∶2ω6 and 22∶2ω6 and desaturated by a Δ6 desaturase to 18∶3ω6. α‐Linolenate was also desaturated by a Δ6 desaturase to 18∶4ω3 and elongated to 20∶3ω3. The copepod was able to convert α‐18∶3 to 20∶5ω3 and 22∶6ω3.
Cholesterol metabolism in the liver and intestine of the chick: Effect of dietary cholesterol, taurocholic acid and cholestyramine
Authors: Sklan D. , Budowski P.
Published: November 2006

The effect of feeding cholesterol, taurocholic acid, or cholestyramine to chicks on cholesterolgenesis from [1‐14C] acetate in liver and intestine was determined in vitro using tissue slices, and in vivo by i.v. injection of [14C] acetate. The conversion of cholesterol to bile acids in liver in vivo was measured in the same treatments after i.v. injection of [3H] cholesterol. Hepatic cholesterogenesis in vitro and in vivo was depressed by dietary cholesterol and taurocholate and enhanced by cholestyramine. Intestinal cholesterogenesis in vivo was depressed only by taurocholate whereas ileal cholesterogenesis in vitro was reduced by dietary cholesterol. Conversion of cholesterol to bile acids was enhanced by dietary cholesterol and cholestyramine and depressed by taurocholate. Hepatic cholesterol metabolism in the chick appears to be regulated by mechanisms similar to those reported for other species.
The effect of exercise on plasma high density lipoproteins
Authors: Wood Peter D. , Haskell William L.
Published: November 2006

The influence of vigorous activity in man on plasma lipids and lipoproteins is reviewed, with particular emphasis on high density lipoproteins. Both cross sectional and longitudinal (or training) studies have been reported, many of them of less than ideal design. Nonetheless, a consistent pattern emerges in which increased exercise levels lead to lower plasma concentrations of triglycerides and very low density lipoproteins, and of low density lipoproteins. High density lipoprotein levels increase. Sometimes, but not uniformly, plasma total cholesterol level falls as the result of these changes. The increase in plasma high density lipoprotein appears to be the result largely of an increase in the less dense HDL2 subfraction. Plasma apolipoprotein A‐I levels (but not apo‐A‐II levels) seem to increase concomitantly. The precise biochemical mechanism responsible for these changes has not been elucidated; but the recent finding of increased lipoprotein lipase activity in adipose tissue and muscle of endurance runners suggests that increased lipolytic rate of trigly ceride‐rich lipoproteins may be an initial step in a sequence of events leading to higher plasma levels of HDL2.
Studies on biosynthesis of waxes by developing jojoba seed. II. the demonstration of wax biosynthesis by cell‐free homogenates
Authors: Pollard Michael R. , McKeon Tom , Gupta Lata M. , Stumpf P. K.
Published: November 2006

The following enzyme activities were demonstrated in cell‐free homogenates from developing jojoba cotyledons: 1) elongation of long chain acyl‐CoAs in the presence of malonyl‐CoA and NADPH (or NADH), 2) NADPH‐dependent reduction of long chain acyl‐CoAs to the corresponding alcohols, 3) esterification of long chain acyl‐CoAs and the alcohols produced from them into wax, 4) elongation of stearoyl‐ACP to eicosanoate and docosanoate as well as reduction to stearyl alcohol, 5) desaturation of stearoyl‐ACP to oleate in the presence of reduced ferredoxin, and 6) incorporation of malonyl‐CoA into long chain fatty acids and alcohols in the presence of added acyl carrier protein. These activities were associated entirely with the floating wax pad after centrifugation of the cell‐free homogenate at 12,000 g for 20 min. The relevance of the above reactions (1–6) to wax biosynthesis in vivo is discussed. Production of oleate from acetate by enzymes utilizing ACP‐thioesters as substrates followed by conversion of oleyl‐ACP to oleoyl‐CoA (via free oleic acid) for subsequent elongation, reduction, and esterification, is presented as the most probable in vivo pathway, for wax biosynthesis. The substrate specificities of the elongation and reduction reactions utilizing acyl‐CoAs as substrates are examined in terms of wax composition.
Studies on cell proliferation in inguinal adipose tissue during early development in the rat
Authors: Gaben‐Cogneville A. M. , Swierczewski E.
Published: November 2006

[2‐14C] Thymidine was injected into rats aged 3, 5 and 10 days, and incorporation of the precursor into deoxyribonucleic acid (DNA) of the inguinal fat tissue was measured for short time periods. Using chromatographic procedures to measure the distribution of thymidine and its metabolites in the soluble fraction of the tissue, degradation of the precursor was found to be similar at all ages. The data indicate that thymidine was more rapidly utilized for DNA synthesis in 3‐day‐old rats than in older animals. When14C‐thymidine was injected in vivo and adipocytes and stromal cells were then separated from the inguinal tissue of 3‐and 5‐day‐old rats, the incorporation into DNA was significant in both types of cells already 30 min after pulse labeling. Stromal cells took up twice as much of label as the adipocytes. Furthermore, real incorporation into DNA was found in the adipocytes when incubated in vitro in a culture medium supplemented with14C‐thymidine. The possibility is discussed that early in postnatal life adipocytes might synthesize DNA for further cell division.
Preparation of cupric palmitate membrane, its characterization and evaluation of thermodynamically effective fixed charge density
Authors: Nasim Beg M. , Siddiqi Fasih A. , Husain Akmal , Islam Badrul
Published: November 2006

Membrane potentials have been measured across, parchment‐supported cupric palmitate membrane separating various 1∶1 electrolytes at concentrations C1 and C2 such that C2=10 C1. Membrane potential data have been used to calculate transference number of ions, permselectivity and also to derive the thermodynamically effective fixed charge density which is an important characteristic governing the membrane phenomena, by utilizing the generally accepted and most widely used theory of Teorell‐Meyer and Sievers as well as the recent theories for membrane potential of Kobatake et al. and Nagasawa et al. based on the principles of nonequilibrium thermodynamics. The values of charge densities derived from different theories were almost the same, confirming thereby the validity of the recently developed theories of membrane potential.
Biliary cholesterol absorption in normal and L‐thyroxin‐fed rats
Authors: Lutton C. , Brot‐Laroche E.
Published: November 2006

Infusion of bile containing labeled cholesterol into bile fistula rats has permitted an in vivo study of the movements and of the absorption of biliary cholesterol in the digestive tract. The specific activities of cholesterol were similar in the micelles and the sediment of the luminal content after a 6 hr infusion, indicating rapid exchange of cholesterol between these fractions. In animals fed a basal diet, the biliary cholesterol absorption was higher (83%) than that of dietary cholesterol (70%). Bile cholesterol is essentially absorbed in the jejunum while the absorption of cholesterol from the diet takes place all along the small intestine but preferentially in its second and third quarters. Both alimentary cholesterol and bile cholesterol enter the top cells of the villi in preference to those of the crypts. In L‐thyroxin‐fed rats, a parallel decrease in biliary and dietary cholesterol absorption was observed. The increase in the intestinal transit of cholesterol and epithelium cell renewal of the jejunum accounted for this observation.
De novo fatty acid synthesis and fatty acid elongation catalyzed by subcellular fractions from hog and human aorta
Authors: Slakey Linda L. , Ferrick Thomas J. , Ness Gene C. , Porter John W.
Published: November 2006

De novo synthesis and mitochondrial elongation of fatty acids have been demonstrated in subcellular fractions from hog and human aorta. Microsomal fatty acid elongation has been shown in hog aorta. The activity catalyzing the formation of fatty acids from acetyl and malonyl CoA was associated with a high molecular weight complex in the 6×106g×min supernatant fraction. The principal product was palmitic acid. Some myristic and stearic acids were also formed. One elongation system was associated with protein which sedimented between 4500 g×min and 150,000 g×min. It used acetyl CoA but not malonyl CoA, and NADH was the preferred reducing agent. Radioactivity from acetyl CoA was incorporated into many fatty acids. In hog aorta a second elongation system was found associated with protein which sedimented at 6×106 g×min. It used malonyl CoA preferentially as substrate and either NADH or NADPH as reducing agent.
Utilization of various sterols by lecithin‐cholesterol acyltransferase as acyl acceptors
Authors: Piran Uri , Nishida Toshiro
Published: November 2006

Highly purified lecithin‐cholesterol acyltransferase of human plasma was used to study the utilization of various sterols as the acyl acceptor. The esterification of sterols was facilitated by the presence of a 3β‐hydroxyl group and thetrans configuration of the A/B rings, as was evident from the lack of acceptor activity of all 3α‐hydroxy sterols tested and coprostanol. Cholesterol analogs in which the side chain is modified, such as campesterol, β‐sitosterol, desmosterol and stigmasterol, were less effective than cholesterol as acyl acceptors. However, androstan‐3β‐o1, which completely lacks the side chain, was found to be more active than cholesterol. The transfer of the acyl group to all effective sterols required the presence of the cofactor peptide apolipoprotein A‐I.
β‐oxidation of the coenzyme A esters of vaccenic, elaidic, and petroselaidic acids by rat heart mitochondria
Authors: Lawson Larry D. , Kummerow Fred A.
Published: November 2006

Rates of β‐oxidation of the coenzyme A esters of vaccenic, elaidic, and petroselaidic acids as well as their respectivecis isomers by rat heart mitochondria were measured and compared. At all concentrations studied, vaccenoyl‐CoA was oxidized more rapidly than elaidoyl‐CoA, but more slowly than oleoyl‐CoA except at high substrate concentrations. Alltrans octadecenoyl‐CoA esters were oxidized at a slower rate than their respectivecis or saturated isomers. Oxidation rates decreased as the double bond approached the carboxyl‐end.
Isolation and identification of the metabolites of 22,25‐dideoxyecdysone from cockroach fat body cultures
Authors: Thompson Malcolm J. , Robbins William E. , Dutky Samson R. , Marks Edwin P. , Filipi Patricia A. , Finegold Harold
Published: November 2006

Hydroxylation and conjugation were the principal pathways of metabolism of 22,25‐dideoxyecdysone in cockroach fat body cultures. The major metabolite isolated and identified was the tetrahydroxy steroid 22‐deoxyecdysone; other exdysteroids isolated, in order of decreasing quantities, were 22‐deoxy‐26‐hydroxyecdysone, 22,25‐dideoxy‐26‐hydroxyecdysone, and 22‐deoxy‐20‐hydroxyecdysone. Cockroach fat body from late‐instar nymphs appears to lack the mechanism for hydroxylating at C‐22. Radioanalyses of the material obtained from enzymic hydrolysis of the conjugate fraction showed 65, 15 and 20% of tetraols, pentaols, and unhydrolyzed conjugates respectively, and no 22,25‐dideoxyecdysone. An azasteroid and two nonsteroidal amines that effectively inhibit the activity of 22,25‐dideoxyecdysone in the cockroach leg regenerate‐fat body culture system enhanced the metabolism of 22,25‐dideoxyecdysone, decreased the quantity of the pentaol fraction present, and caused an increase or accumulation of the tetraol and conjugate fractions in the fat body culture system.
Uptake and utilization of 1‐14C palmitic acid by heart cells treated with fresh or thermally oxidized fats
Authors: Bird Ranjana P. , Alexander J. C.
Published: November 2006

The effects of fractions isolated from thermally oxidized corn oil or olive oil on the metabolic activity of heart endothelial and muscle cells were studied. Rat heart cells in culture, exposed to thermally oxidized fat components, took up more exogenous 1‐14C‐palmitic acid and incorporated more of it into the cell triacylglycerol fraction than when the cells were treated with fresh fats. Particularly with the heated corn oil compared to fresh corn oil, much less of the radioactivity from the labeled palmitic acid was deposited in the phospholipid fraction. Also, with heated corn oil when the incubation period was extended beyond 12 hr, there was a decline in the radioactivity retained in the triacylglycerol fraction of the heart muscle cells. When the fresh fats were compared for14C‐radioactivity incorporation into the heart cells, the olive oil gave much higher values, indicating a distinct difference in response to the proportion of fatty acids supplied.
Alpha tocopherol levels in various regions of the central nervous systems of the rat and guinea pig
Authors: Vatassery G. T. , Younoszai R.
Published: November 2006

The alpha tocopherol contents of various discrete anatomical regions in the central nervous system of adult rats and guinea pigs were assayed using a liquid chromatographic method. All parts of the guinea pig nervous system had lower alpha tocopherol contents per gram wet, dry or lipid weights than the corresponding areas in the rat. In both animals the distribution of alpha tocopherol did not correspond to the distribution pattern of total lipid. There was also a rostral to caudal concentration gradient with respect to alpha tocopherol content; gray matter from cerebral hemisphere has the highest concentration and cervical spinal cord the least. In both animals alpha tocopherol contents per gram dry weight or lipid weight were higher in gray matter areas when compared with white matter areas. The low concentration of alpha tocopherol in spinal cord could make this region more susceptible to damage from deficiency than the rest of the central nervous system.
Isolation and characterization of phospholipase D from fababeans
Authors: Atwal A. S. , Eskin N. A. M. , Henderson H. M.
Published: November 2006

An enzyme activity in crude extract of fababeans hydrolyzed phosphatidylcholine‐U‐14C to produce choline and phosphatidic acid. This enzyme, phospholipase D, was stable at 50 C in the presence of 5 mM DTT but was inactivated at 55 C. The enzyme was precipitated with cold acetone, concentrated between 30% saturation to 40% saturation with ammonium sulphate, absorbed on calcium phosphate gel and eluted with 0.2 M phosphate buffer. This procedure resulted in a 20‐fold increase in specific activity. The activity of fababean phospholipase D was much higher when assayed at 38 C than that at room temperature. There was an obligatory requirement for calcium, and for maximal activity 40 mM calcium was required. A narrow pH optimum of about pH 5.7 was observed. The enzyme activity was extremely dependent on substrate dispersion. When 5 mM phosphatidylcholine (PC) was sonicated with increasing levels of sodium dodecyl sulphate (1 mM to 4 mM), the enzyme activity kept increasing. By using equimolar concentrations of PC and sodium dodecyl sulphate (1 mM to 5 mM), the Michaelis constant (Km) was estimated to be 1.74 mM. Addition of choline and serine at 10 mM concentration reduced phospholipase D activity by 31% and 22%, respectively.
Differential alteration of Δ9 and Δ6 desaturation of fatty acids in rat brain preparations in vitro
Authors: Cook H. W.
Published: November 2006

Developing rat brain has the capacity for either Δ9 or Δ6 desaturation of fatty acids. In liver, evidence supports the existence of separate enzymes for each reaction, but it is not known whether in brain Δ9 or Δ6 desaturation of saturated fatty acids involves distinct enzymes. We have used fatty acids, including the cyclopropene fatty acid, sterculic acid, to alter desaturation activities with substrates that are desaturated predominantly in the Δ9 position or in the Δ6 position. In addition, differential alteration of desaturation of plamitic acid, a substrate that can be desaturated in either the Δ9 or Δ6 positions by brain preparations from neonatal rats, was examined. Sterculate reduced Δ9 desaturation of palmitate 80–90% but reduced Δ6 desaturation only 35%. In contrast, linoleic acid preferentially reduced Δ6 desaturation of palmitate. Thus, Δ9 desaturation of saturated fatty acids appears to be catalyzed by an enzyme or enzyme site distinct from that for Δ6 desaturation. Accordingly, these activities may be independently regulated during crucial stages of brain development.
Lipid composition of morris hepatoma 5123c, and of livers and blood plasma from host and normal rats
Authors: Ruggieri S. , Fallani A.
Published: November 2006

The lipid composition of Morris hepatoma 5123c was analyzed together with that of liver and blood plasma from both normal and tumor‐bearing rats. The results showed that the liver of tumor‐bearing rats contained higher amounts of glycerides, cholesteryl esters, free fatty acids and phospholipids than the liver of normal rats. In the blood plasma of tumor‐bearing rats, there was an increase of free cholesterol and triglycerides; this latter difference, however, was not statistically significant. Acyl chain changes in the liver of tumor‐bearing rats consisted of an increase of palmitic and oleic acids and a decrease of stearic and arachidonic acids in phosphatidylinositol. Morris hepatoma 5123c contained a lower amount of triglycerides than the livers (both host and normal) and showed a significant decrease of total phospholipids when compared to the host liver. The major acyl chain changes found in Morris hepatoma 5123c compared with both normal and host rat livers were: a) a higher percentage of arachidonic acid together with a lower proportion of palmitic acid in cholesteryl esters; b) an increase of stearic and arachidonic acids and a decrease of palmitic acid in triglycerides; and c) a higher level of palmitic and oleic acids associated with a lower percentage of stearic and C22 polyunsaturated acids in phosphatidylcholine.
The influence of phthalate esters on human plasma lecithin/cholesterol acyltransferase
Authors: Lagente M. , de la Farge F. , Valdiguie P.
Published: November 2006

The effect of various phthalate esters on the lecithin/cholesterol acyltransferase activity in man was studied in vitro. The enzymatic activity was strongly reduced with all phthalates except for the dimethyl phthalate. The inhibition rate depends on the phthalate concentration and also on the carbon number of the alkyl groups of phthalates.
Uptake of [14C] choline and incorporation into lung phospholipid by the isolated perfused rat lung
Authors: Johnson Rodger G. , Lugg Moira A. , Nicholas Terence E.
Published: November 2006

We have used the isolated perfused lung (IPL) preparation from the rat to determine whether uptake of choline from the vascular compartment could limit the rate of synthesis of phosphatidylcholine (PC). The uptake of choline was rapid and did not saturate at a concentration of 10 mM. The rate of incorporation of choline into phospholipid was saturated above 0.1 mM choline. Whereas, uptake and incorporation were depressed at 4 C, uptake was neither dependent on the extracellular sodium concentration nor inhibited by equimolar concentrations of hemicholinium‐3 (HC‐3). We could find no evidence that uptake might limit synthesis of lung lecithin and conclude that uptake is either by free diffusion, or by a carrier‐mediated process with a very high Km.
Identification of novel octadecadienoic fatty acids in the seaweedCladophora rupestris through oxidative ozonolysis of the alcohols prepared from the acids
Authors: Ratnayake W. N. , Ackman R. G.
Published: November 2006

The BF3−MeOH reagent for ozonolysis of ethylenic unsaturation does not oxidize alcohols. It is therefore feasible to determine the position of ethylenic unsaturation in long chain fatty alcohols of synthetic or natural origin by recovering the methyl ester products intact and silylating the alcohol function of half‐ester, half‐alcohol, products prior to gas liquid chromatographic analysis. The C3 fragment from methylene‐interrupted alkyl chains is not recovered, but, by first reducing carboxyl ester groups to alcohols, the terminal difunctional products can be identified in nonmethylene‐interrupted dienoic fatty acids. The seaweedCladophora rupestris is shown to contain Δ5,Δ11‐,Δ8,Δ11‐, and Δ11, Δ14‐ as well as Δ9,Δ12‐octadecadienoic acid.
Separation and identification of prostaglandin A1 in onion
Authors: Attrep Katherine A. , Bellman William P. , Attrep Moses , Lee James B. , Braselton W. E.
Published: November 2006

The separation of a fraction corresponding to prostaglandin A1 from yellow onion (Allium cepa) and subsequent purification of that fraction as prostaglandin A1 has led to the identification of prostaglandins in a plant material for the first time. Kilogram quantities of onions were processed and purified by extraction procedures, column chromatography and thin layer chromatography (TLC). Prostaglandin A1 was characterized and identified by a combination of comparative TLC, gas chromatography‐mass spectrographic analysis and blood pressure lowering properties. The results of these experiments are consistent with standard prostaglandin A1. It is concluded that prostaglandin A1 is present in onion.
Relative susceptibility of microsomes from lung, heart, liver, kidney, brain and testes to lipid peroxidation: Correlation with vitamin E content
Authors: Kornbrust Douglas J. , Mavis Richard D.
Published: November 2006

Rates of in vitro lipid peroxidation of microsomes and homogenates were found to vary widely among different tissues and species. In rats and rabbits, lung microsomes peroxidized at a 25‐ to 50‐fold lower rate than liver, kidney, testes and brain microsomes. Heart microsomes peroxidized at a rate slightly greater than, but most similar to, lung microsomes. Comparison of tissue homogenates also revealed the unique resistance of lung and heart to lipid peroxidation. The ratio of vitamin E to peroxidizable polyunsaturated fatty acids in lung and heart microsomes was several‐fold higher than in microsomes from the other tissues studied, which accounted for the relative resistance of lung and heart to lipid peroxidation. Liposomes of extracted rat lung microsomal lipid were also resistant to peroxidation and the amount of vitamin E contained in the lung lipid extract was sufficient to confer the same degree of resistance when incorported into an equivalent amount of rat liver lipid. Higher rates of peroxidation in mouse lung microsomes relative to rabbit, rat and human lung microsomes were similarly correlated with a lower ratio of vitamin E to peroxidizable fatty acids in mouse lung microsomes. These data provide strong support for the role of vitamin E as the major cellular antioxidant, especially in the highly oxygenated tissues of heart and lung, and demonstrate the utility of the microsomal system in characterizing tissue differences in susceptibility to peroxidative membrane decomposition.
Skin surface lipids of the horse
Authors: Downing Donald T. , Colton Vi Sabin W.
Published: November 2006

Skin surface lipids from the sides of male and female horses (Equus caballus) were collected in acetone and analyzed by thin layer chromatography and gas liquid chromatography. The sole components in both sexes were cholesterol, cholesteryl esters and the lactones of 32‐, 32‐ and 36‐carbon ω‐hydroxy acids, each including a methyl group in the n−1 position. Most of the lactones were mono‐unsaturated (either n−8 or n−10), but small amounts of saturated and dienoic species were present. A pooled sample of the skin surface lipids contained 14% cholesterol, 38% cholesteryl esters and 48% lactones.
Analysis of subcellular phosphatidyl choline in developing rabbit lung
Authors: Gutcher Gary R. , Zachman Richard D. , Tsao Francis H. C.
Published: November 2006

Phosphatidyl choline is a major lung surfactant. Insufficient development of the surfactant in neonates is often associated with the Respiratory Distress Syndrome. The concentration and fatty acid composition of phosphatidyl choline have not been studied in the subcellular organelles of the developing lung. This study has investigated the development of the concentration and fatty acid composition of phosphatidyl choline in subcellular fractions of 28‐day and 30‐day fetal and maternal New Zealand rabbit lungs. The concentration of total phospholipids in lamellar bodies increased four to five fold from 28‐day fetus to 30‐day fetus which, in turn, was similar to the maternal level. Total phospholipid content increased only about 50% in mitochondria and microsomes. The percentage of phosphatidyl choline among total phospholipids in lamellar bodies increased successively from 60% at 28 days gestation to 84% at 30 days gestation and leveled at 84% in maternal lamellar bodies. Microsomal PC increased steadily from 52% in the 28‐day fetus to 65% in the adult. Analysis of the fatty acid composition of phosphatidyl choline in lamellar bodies confirmed 16∶0 as the major fatty acid, and its content remained constant from 28 days gestation to adult. In contrast, the content of 16∶0 of the microsomal phosphatidyl choline decreased with increasing gestation. Changes of several unsaturated fatty acid components were observed in both lamellar bodies and microsomes in the developing lungs. Maturational development of phosphatidyl choline is reflected in an increase in the concentration of this surfactant, particularly in lamellar bodies, and possibly in remodeling of fatty acid composition in both lamellar bodies and microsomes.
Lipogenesis in the developing brain: Utilization of radioactive leucine, isoleucine, octanoic acid and β‐hydroxybutyric acid
Authors: Dhopeshwarkar Govind A. , Subramanian Carole
Published: November 2006

Incorporation of radioactivity from intracranially injected radioactive leucine, isoleucine (ketogenic amino acids), octanoic acid and β‐hydroxybutyric acid into the brain lipids of 15 to 16 day‐old rats was examined. The results showed that radioactivity from all the above precursors was incorporated into brain lipids. Radioactivity from injected isoleucine was incorporated into odd numbered fatty acids indicating an alternate pathway to α‐oxidation for the biosynthesis of these fatty acids in the brain. For some as yet unclear reasons, a substantial portion of the radioactivity from injected octanoic acid was incorporated into free fatty acids. Utilization of these compounds for providing carbon for lipogenesis during development under unstressed normal conditions is discussed.
Isolated brain capillary endothelia: Influence of various levels of essential fatty acids on the acyl group composition of glycerophospholipids
Authors: Selivonchick Daniel P. , Roots Betty I.
Published: November 2006

On day seven of gestation, Wistar rats were assigned to a high essential fatty acid (EFA), low EFA, or a fat free diet. The same diets were continued during lactation. On weaning, the offspring were fed the same diets as their mother. Rats were killed at 222 days, brain capillary endothelia isolated, and total lipids extracted from the purified capillaries. The composition of the constituent fatty acids of ethanolamine glycerophospholipid (EGP), choline glycerophospholipid (CGP), and the alk‐1‐eny EGP composition from each diet is reported. A decrease in dietary EFA led to reduced proportions of total saturated acyl groups in EGP with no change observed in the total saturated acyl groups from CGP, and an increase in monoenoic fatty acids, particularly 18∶1n−9 for each phospholipid class. The proportions of 20∶4n−6 in alk‐1‐enyl EGP were reduced in fat‐free fed animals. In addition, the relationship between 20∶3n−9 and 20∶4n−6 fatty acids in brain capillary endothelia were markedly increased with a reduction in dietary fat. Low EFA and fat deficient animals showed a tendency to sequester 22∶6n−3.
Correlation in the proportion of oleic to vaccenic acid of plasma phospholipids with the early stages of hepatoma 7288CTC growth
Authors: Mapes James P. , Wood Randall
Published: November 2006

The major octadecenoate isomers, oleate (Δ9) and vaccenate (Δ11), were measured in the plasma phospholipids of rats bearing hepatoma 7288CTC as the tumor developed. The percentage of vaccenate decreased from 45% of the octadeceoate fraction at day zero to 25% by the 15th day. A significant decrease (45% to 35%) in the percentage of vaccenate occurred by the sixth day, well in advance of detectable tumor growth. The percentage of vaccenate continued to decrease as a function of time until day 15, after which it remained constant. Detection of alterations in plasma phospholipids at an early stage of tumor development in rats suggests that experiments should be carried out to determine if the same effects occur in humans.
Identification of thetrans isomers of octadecenoic acid in human milk
Authors: Picciano Mary Frances , Perkins Edward G.
Published: November 2006

The presence oftrans octadecenoic acid isomers was detected and analyzed in 24 hr pooled samples of human milk. Amounts of thetrans isomers of the C18 monoenes ranged from 2% to 4% of the total fatty acids. For purposes of comparison, three commonly used brands of infant formula were also analyzed and found to contain 0.1% to 1.3% oftrans monoene isomers. Data indicate that breast‐fed and bottle‐fed infants are receiving minimal levels oftrans fatty acids via milk.
Gangliosides of cultured cells of a rat mammary carcinoma cell line
Authors: Keenan T. W. , Schmid Erika , Franke Werner W.
Published: November 2006

Ganglioside content of rat mammary carcinoma‐derived cells grown in layers in vitro was nearly as high as that of apical plasma membrane‐derived milk fat globule membrane and nearly four times higher than the content of normal, lactating mammary tissue on a protein basis. The major ganglioside of these carcinoma‐derived cells was identified as GDla (sialic acid‐Gal‐GalNAc‐(sialic acid)‐Gal‐Glc‐Cer. Relative to carcinoma‐derived cells, rat mammary tissue and milk fat globule membrane had more complex ganglioside patterns but appeared to lack substantial quantities of GDla.
Lipid composition and biosynthesis of human omental tissue
Authors: Rabinowitz Joseph I. , Askins Sarvertia E. , Luddy Francis E.
Published: November 2006

Two groups of five males each were selected for total lipid analyses of their omental tissue. One of these groups had been subjected to a severe caloric restriction and had undergone total weight reduction of about 20%. The other group served as control. Both of these groups of patients required elective surgical procedures during which it was possible to obtain small samples of omental tissue, adipose pad, and/or mesenteric tissue. Total lipid analyses were performed on all of the materials. A distinctive positional distribution of the acyl groups was maintained in the triglycerides of omental tissue for all the patients regardless of dietary state. Patients under caloric restriction showed a reduction in their total triglyceride content, a reduction in their content of unsaturated fatty acyl groups, and a relative increase in phospholipid content. The de novo lipid biosynthetic capacity of omental tissues, as determined by 1‐[14C]‐acetate incorporation, showed an inverse proportionality to the lipid content of the samples. Omental tissue is biosynthetically a very versatile material capable of yielding rapidly many types of fatty acids. This ability, among others, could account for the usefulness of omental tissue as a supporting base in many types of restorative surgery.