Showing papers in "Lipids in 1976"
TL;DR: The nature and mechanism of formation of the thiobarbituric acid (TBA)-reactive material produced in the autoxidation of polyunsaturated fatty acids (PUFA) or their esters has been studied.
Abstract: The nature and mechanism of formation of the thiobarbituric acid (TBA)-reactive material produced in the autoxidation of polyunsaturated fatty acids (PUFA) or their esters has been studied. On the basis of chemical studies and
490 citations
TL;DR: A sensitive, highly reproducible method for tissue tocopherol analysis that combines saponification in the presence of large amounts of ascorbic acid to remove interfering substances, extraction of the nonsaponifiable lipids with hexane, and fluorometric measurement of the toCopherol is presented.
Abstract: A sensitive, highly reproducible method for tissue tocopherol analysis that combines saponification in the presence of large amounts of ascorbic acid to remove interfering substances, extraction of the nonsaponifiable lipids with hexane, and fluorometric measurement of the tocopherol is presented. The nonsaponifiable lipid phase contained only one fluorochrome in the 290 nm excitation and 330 nm emission range, and it was identified as tocopherol by thin layer and column chromatography. Column chromatography of the hexane extract of a saponified,14C-tocopherolspiked microsomal fraction showed that no measurable oxidation to tocopherylquinone has occurred. The fluorometric method for tocopherol analysis was applied to homogenates and subcellular fractions from rat liver, kidney, lung, and heart and red blood cells. The heavy mitochondrial and microsomal fractions had the highest subcellular concentrations of tocopherol.
320 citations
TL;DR: Commercial soybean lipoxygenase may be used under carefully controlled reaction conditions to give high yields of lipid hydroperoxides so derived from γ-linolenic or arachidonic acid.
Abstract: Commercial soybean lipoxygenase may be used under carefully controlled reaction conditions to give high yields of lipid hydroperoxides. Lipid hydroperoxides so derived from γ-linolenic or arachidonic acid may be purified by high pressure liquid chromatography. Thus, commercial lipoxygenase serves as a viable source for 100 mg quantities of lipid hydroperoxides.
212 citations
TL;DR: Purified lipofuscin pigments from blood, lung, liver, spleen, brain, heart, and kidney tissues demonstrated distinct fluorescent emission maximum at 435 nm and excitation maxima between 345 and 350 nm.
Abstract: Lipofuscin pigment determination in tissue extracts was quantitated by the use of its property of fluorescence. Chloroform: methanol tissue extracts were purified on Sephadex LH-20 columns before quantitative fluorescence measurements of the lipofuscin pigments. Interfering compounds separated by chromatography were retinol and a lower mol wt fluorescent compound. Irradiation of tissue extracts with ultraviolet light was not sufficient to eliminate the interference caused by retinol and the lower mol wt compound. Purified lipofuscin pigments from blood, lung, liver, spleen, brain, heart, and kidney tissues demonstrated distinct fluorescent emission maximum at 435 nm and excitation maxima between 345 and 350 nm.
113 citations
TL;DR: Fatty acid distribution patterns in yeast cells consistently coincided with other reports concerning fatty acid composition of yeast cells, and correlation of lipid composition and classification of yeasts is suggested and discussed.
Abstract: The detailed composition of cellular lipid of more than 23 species of yeast has been determined quantitatively by thinchrography on quartz rods, a method previously used for estimating cellular lipids of seven species of yeast. That data was fortified by neutral and phospholipid quantitations on 30 species of yeast cells. Most of the test organisms contained 7-15% total lipid and 3-6% total phospholipid per dry cell weight, except for the extremely high accumulation of triglycerides in two species of Lipomyces. Qualitatively, 30 species of yeast cells contained similar neutral lipid constituents (triglyceride, sterol ester, free fatty acid, and free sterol) and polar lipid components (phosphatidyl choline, phosphatidyl ehtanolamine, phosphatidyl serine, phosphatidyl inositol, cardiolipin, and ceramide monohexoside) without minor constituents. Based on the quantitative composition of neutral lipids, the 30 species of yeast were divided into two groups , the triglyceride predominant group and the sterol derivative group. These groupings were fairly well overlapped from the standpoint of the distribution characteristics of fatty acid. The relative polar lipid compositions also grossly resembled each other. Only one exception of polar lipid composition in yeast cells was found in Rhodotorula rubra species which contained phosphatidyl ethanolamine as the most abundant phospholipid. Fatty acid distribution patterns in yeast cells consistently coincided with other reports concerning fatty acid composition of yeast cells. Correlation of lipid composition and classification of yeasts are suggested and discussed.
112 citations
TL;DR: All the homologs of the α-linolenic series were found in the clam without any important changes and six hour administration of labeled linolenic acid resulted in the incorporation of the acid into diglycerides and phospholipids.
Abstract: The fate of labeled linoleic, α-linolenic, and higher homologs of α-linolenic acid administered to the yellow clam,Mesodesma mactroides, was investigated. It was found that the clam incorporated the acids dissolved in sea water and converted 18∶2 (n−6) into 20∶2 (n−6) and 18∶3 (n−3) into 18∶4 (n−3) and 20∶3 (n−3). The addition of casein hydrolysate to the sea water increased the desaturation capacity of the clam and allowed the conversion of 18∶2 (n−6) into 18∶3 (n−6) to be demonstrated. An enhanced desaturation of 18∶3 (n−3) into 18∶4 (n−3) was also demonstrated. After 12 hr administration of the acid, no radioactivity was found in arachidonic, 20∶5 (n−3), or 22∶6 (n−3). Feeding the clams a culture ofPhaeodactylum tricornutum previously incubated with 1-14C-α-linolenic acid demonstrated that all the homologs of the α-linolenic series were found in the clam without any important changes. Six hour administration of labeled linolenic acid resulted in the incorporation of the acid into diglycerides and phospholipids.
97 citations
TL;DR: In this article, the authors found that fish are able to adjust the pattern of the biosynthesis of fatty acids very rapidly to the prevailing temperature and to assure by this way the proper physicochemical properties of their membranes.
Abstract: Incorporation in vivo of sodium 1-14C-acetate into different lipid classes and fatty acids of total lipids and phospholipids of warm adapted and cold adapted carp livers was studied at 5 C and 22 C, respectively. The fatty acid composition of total lipids and phospholipids was also determined. The level of long chain polyunsaturated fatty acids in both total lipid and phospholipid fractions was higher in cold adapted fish than in warm adapted ones. The distribution of radioactivity among different lipid classes depended only on the actual incorporation temperature and was independent of the temperature history of the animals. Livers of fish incorporated a higher percentage of radioactivity into long chain polyunsaturated fatty acids of total lipids and phospholipids in 5 C than in 22 C. The distribution of radioactivity among different fatty acids was dependent on the experimental temperature rather than on the temperature to which the fish were adapted. The results suggest that fish are able to adjust the pattern of the biosynthesis of fatty acids very rapidly to the prevailing temperature and to assure by this way the proper physicochemical properties of their membranes. The possible mechanisms involved in this rapid response are discussed.
97 citations
TL;DR: The field positions of sulfur resonance in cysteine and proteins suggested a sulfur-oxygen complex rather than thiyl radicals, and free radicals produced in proteins primarily showed central singlet lines, attributable to carbon-centered radicals.
Abstract: Free radical transfer from oxidizing methyl linoleate to amino acids and proteins was studied in dry model systems incubated for periods up to 20 days. Electron spin resonance was used to study free radical production. Free radicals were detectable in the amino acids lysine, arginine, histidine, tryptophan, and cysteine. Reduced glutathione and, to a limited extent, cystine also gave free radical signals. Free radicals produced in proteins primarily showed central singlet lines, attributable to carbon-centered radicals, with g=2.004±0.001. Sulfhydryl proteins also exhibited downfield shoulders at g≄2.015 and 2.023 that were essentially identical to peaks observed in cysteine and reduced glutathione. The field positions of sulfur resonance in cysteine and proteins suggested a sulfur-oxygen complex rather than thiyl radicals.
93 citations
TL;DR: Generally, the prokaryotic blue-green algae show a simpler hydrocarbon composition than the eucaryotic green algae, which contain higher amounts of high mol wt components.
Abstract: As part of a program to study the chemical composition of algal biomasses, the composition of the unsaponifiable matter of the lipids of ten algal species (fiveMyxophyceae and fiveChlorophyceae) was investigated. The total unsaponifiable content, its general composition, and the components of the hydrocarbon fraction are discussed in the present paper. The unsaponifiable content of green algae is constantly higher than that of the blue-green ones, with the exception ofChlorella. In both algal classes, the major components are hydrocarbons and sterols. Blue-green algae are richer in hydrocarbons, whereas the green ones contain higher amounts of sterols. In most of the species examined, at least 48 components are present in the hydrocarbon fraction. Each algal species shows a characteristic gas liquid chromatography pattern, but n-C17 is always one of the most abundant components. Generally, the prokaryotic blue-green algae show a simpler hydrocarbon composition than the eucaryotic green algae, which contain higher amounts of high mol wt components. Unsaturated hydrocarbons are generally present in very limited quantities, with the exception ofSpirulina sp. andChlorella, sp., which contain a C17 alkene. Green algae also contain appreciable amounts of a C27 monoene and of squalene.
82 citations
TL;DR: In this article, it was shown that 24-ethylcholesterol was consistently an epimeric mixture, with the 24α-epimer present in about twice the concentration of the 24β -epimer.
Abstract: 24-Ethylcholesterol was shown by proton magnetic resonance spectroscopy to have only the α-configuration in a series of tracheophytes ranging through the evolutionary hierarchy from ferns through gymnosperms and primitive angiosperms to climax angiosperms. 24-Methylcholesterol, however, was consistently an epimeric mixture, with the 24α-epimer present in about twice the concentration of the 24β-epimer. 24-Methylcholesterol was always present in smaller amount than the 24-ethylcholesterol.
77 citations
TL;DR: Twenty genera of sponges from the class Demospongiae have been examined for fatty acid composition and all contain unusually high levels of C24−C30 fatty acids not generally found in other organisms.
Abstract: Twenty genera of sponges from the class Demospongiae have been examined for fatty acid composition. All contain unusually high levels (34–79%) of C24−C30 fatty acids not generally found in other organisms. These characteristic “demospongic acids” are mostly polyunsaturated.
TL;DR: Analysis of brain fatty acids showed that the saturated acids, 16∶0, and 18∷0, as well as the mono-unsaturated 18∶1, must have been formed from radioactive acetate produced by β oxidation of the injected linolenate.
Abstract: Thirteen-day old rats were given intracranial injections of 1-14C linolenic acid (allcis 9,12,15 octa decatrienoic acid) and were sacrificed after 8 hr. Analysis of brain fatty acids showed that 16∶0, 18∶0, 18∶1, 18∶3, 20∶3, 20∶4, 20∶5, 22∶5, and 22∶6 were labeled. The total fatty acid methyl esters were separated into classes according to degree of unsaturation on a AgNO3∶SiO2 impregnated plate. The bands were scraped off and the eluted fatty acids were first analyzed by radiogas liquid chromatography and then subjected to reductive ozonolysis to determine double bond position. The saturated acids, 16∶0, and 18∶0, as well as the mono-unsaturated 18∶1, must have been formed from radioactive acetate produced by β oxidation of the injected linolenate. Among the polyunsaturated fatty acids, the triene fraction was characterized and identified as 18∶3 e3 (Δ9,12,15), the starting material, and 20∶3 ω3 (Δ11,14,17); the tetraene fraction was identified as 20∶4 ω3 (Δ8,11,14,17); the pentaene fraction was identified as 20∶5 ω3 (Δ5,8,11,14,17) and 22∶5 ω3 (Δ7,10,13,16,19); and, finally, the hexaene fraction was shown to be 22∶6 ω3 (Δ4,7,10,13,16,19). The biosynthesis of these ω3 family fatty acids in the brain in situ is discussed.
TL;DR: It is shown that marine dinoflagellates under natural conditions synthesize the unusual fatty acid octapentadecaenoic (18∶5ω3), which is very likely a characteristic of certain groups of phytoplankters and is not an artifact from artificial culture conditions.
Abstract: It is shown that marine dinoflagellates under natural conditions synthesize the unusual fatty acid octapentadecaenoic (18∶5ω3). This acid is very likely a characteristic of certain groups of phytoplankters and is not an artifact from artificial culture conditions. Various species of herbivorous copepods as well as contemporary carnivorous chaetognaths living in the same environment present traces of this fatty acid. The decreasing quantity of 18∶5ω3 on moving up the food chain, and its absence in certain species, makes it a possible ecological tracer.
TL;DR: High pressure reverse phase liquid chromatography has been employed to rapidly separate saturated and unsaturated fatty acids as the correspondingp-bromophenacyl esters, and the use of ultroviolet-sensitive esters has permitted the detection of low concentrations of fatty acids.
Abstract: High pressure reverse phase liquid chromatography has been employed to rapidly separate saturated and unsaturated fatty acids as the correspondingp-bromophenacyl esters. Through the use of a highly efficient C18 reverse phase column packing, it has also been possible to distinguish among geometrical and positional isomers of the unsaturated acids. The use of ultroviolet-sensitive esters has permitted the detection of low (nanogram range) concentrations of fatty acids. The time required for analysis has been further reduced by employing a novel and rapid method for the preparation of the esters.
TL;DR: In this paper, chemical shifts have been assigned to all the separate signals in the 13C nuclear magnetic resonance spectra of methyl stearate, oleate, and petroselinate by means of the second and third atom isotope effects in spectra specifically deuterated esters.
Abstract: Chemical shifts have been assigned to all the separate signals in the13C nuclear magnetic resonance spectra of methyl stearate, oleate, and petroselinate by means of the second and third atom isotope effects in spectra of specifically deuterated esters. Spectra of almost all the isomeric hydroxy, acetoxy, and oxo stearates were also measured. From the assignments, the effects of the introduction of a double bond or an oxo, hydroxy, or acetoxy group at different positions on the fatty acid chain on the13C nuclear magnetic resonance spectra were determined. All the isomeric oxo stearates and most of the hydroxy and acetoxy stearates can be distinguished and identified by their13C spectra.
TL;DR: Most, if not all, of the plasma GSL are associated with plasma lipoproteins and may have an important role in their biological functions.
Abstract: The content and structure of glycosphingolipids (GSL) in human plasma lipoproteins were studies. The quantitative distribution of the neutral GSL(Glc-Cer, Gal-Glc-Cer, Gal-Gal-Glc-Cer, and GalNAc-Gal-Gal-Glc-Cer) and the principal ganglioside (AcNeu-Gal-Glc-Cer) within the different lipoprotein classes was similar to that of whole plasma. The total amounts (μmol glucose/100 ml plasma) of GSL in the plasma lipoproteins of three normal subjects were VLDL (very low density lipoproteins) (trace to 0.46), LDL (low density lipoproteins) (1.08–1.48), HDL2 (high density lipoproteins2) (0.62–0.85), and HDL3 (high density lipoproteins3) (trace to 0.28). In subjects with Lp(a) lipoproteins, HDL2 rather than HDL3 contained most of the GSL in HDL. When the data were corrected for differences in the plasma concentrations of the lipoproteins, the total amounts of GSL(nmol glucose/mg lipoprotein cholesterol) were VLDL(trace to 21.20), LDL(11.70–15.36), HDL2(8.50–9.10), and HDL3(3.12). No GSL were detected in lipoprotein deficient plasma. Mass spectrometry of the trimethylsilyl derivatives of the GSL in LDL showed major fragment ions characteristic of their individual structural components. The elevated plasma levels of the GSL(2–18 fold), in a homozygote for familial hypercholesterolemia, resided in LDL which contained an absolute increase (per mg lipoprotein cholesterol) of GSL. Most, if not all, of the plasma GSL are associated with plasma lipoproteins and may have an important role in their biological functions.
TL;DR: In this article, the composition of the terpenic alcohol and sterol fractions of ten algal species, fiveMyxophyceae and fiveChlorophycea, is discussed.
Abstract: The composition of the terpenic alcohol and sterol fractions of the unsaponifiables of ten algal species, fiveMyxophyceae and fiveChlorophyceae, is discussed. The major component of the terpenic fraction is phytol, a diterpenic alcohol. Minor amounts of straight chain and triterpenic alcohols are also present. Practically all the species examined contain ten components in the sterol fraction: cholesterol, brassicasterol, Δ5-ergostenol, poriferasterol, Δ7-ergostenol, clionasterol, chondrillasterol, Δ5-avenasterol, Δ7-chondrillastenol, and an unidentified component. Identification of the sterols was made by gas chromatography-mass spectrometry, and a 24 S configuration was assumed. The prokaryotic blue-green algae are characterized by a higher content in cholesterol (3.5–14%) than the eucaryotic green algae (0–2.5). Also, brassicasterol, poriferasterol, clionasterol, and Δ5-avenasterol are more abundant in blue-green algae. Δ7-Ergostenol, chondrillasterol, and Δ7-chondrillastenol predominate, on the contrary, in green algae.
TL;DR: The lipid composition of the yellow clam, Mesodesma mactroides, that lives in the northern beaches of the Buenos Aires province of Argentina was studied and the content of polyunsaturated acids increases in summer together with an increase in nonpolar lipids and is correlative with a increase in phytoplankton in the sea water.
Abstract: The lipid composition of the yellow clam, Mesodesma mactroides, that lives in the northern beaches of the Buenos Aires province of Argentina was studied. The main nonpolar lipids are triglycerides and alkoxyglycerides. Phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl serine are the main phospholipids. The predominant fatty acids are 16:0, 16:1omega7, 18:0, 18:1omega9, 20:5omega3, and 22:6omega3. They are mainly provided by the clam's food and stored in the hepatopancreas. The content of polyunsaturated acids increases in summer together with an increase in nonpolar lipids and is correlative with an increase in phytoplankton in the sea water. Sexual maturity modifies the lipid composition of gametes.
TL;DR: The present results suggest that the enrichment of rat liver phosphatidyl inositol in arachidonic acid may arise when 1-acyl-sn-glycero-3-phosphorylinositol is acylated to form phosph atidylinositol.
Abstract: The conversion of 1-acyl-sn-glycero-3-phosphorylinositol-3H into phosphatidylinositol-3H was studied using rat liver microsomal and homogenate preparations. The nature of the molecular species of phosphatidyl inositol so formed in the absence of added acyl moieties was determined after fractionating the radioactive product by means of argentation thin layer chromatography. In other experiments, the possible specificity of the microsomal acyl-CoA:1-acyl-sn-glycero-3-phosphorylinositol acyltransferase towards different acyl-CoA derivatives was investigated. Maximum conversion of 1-acyl GPI to the diacyl analogue was dependent on the addition of adenosine triphosphate and CoA when exogensou acyl groups were omitted from the incubation medium. Under these latter conditions, the tetraenoic species comprised 56-74% of the total molecular species of newly-formed phosphatidylinositol. The microsomal acyl-CoA:1-acyl-sn-glycero-3-phosphorylinositol acyltransferase showed a marked preference for arachidonoyl-CoA. The present results suggest that the enrichment of rat liver phosphatidyl inositol in arachidonic acid may arise when 1-acyl-sn-glycero-3-phosphorylinositol is acylated to form phosphatidylinositol.
TL;DR: It is postulated that linolenic acid plays a role in the etiology of cardiac necrosis observed when rats are fed diets containing low erucic acid rapeseed oils, comparable to those obtained for low erucaic acid rapessed oil and soybean oil which were similar.
Abstract: Male Wistar rats were fed semipurified diets containing 20% fat for 25 weeks. Ten different oils or oil blends were employed, including rapeseed oils, simulated rapeseed-type oils, and modified rapeseed-type oils. Safflower, soybean, and hydrogenated coconut oils served as control oils. Histopathological examination of the cardiac tissue was conducted at the end of the study and an incidence-severity rating assigned to the lesions induced by each fat. Oils containing high levels of erucic acid (26–30%) induced the most severe cardiac necrosis, irrespective of the source of erucic acid (rapeseed oil or nasturtium oil). Increasing the linoleic: linolenic acid ratio of the high erucic oils to that of soybean oil failed to reduce necrosis, but the absence of linolenic acid from a high erucic acid oil blend resulted in a markedly reduced lesion incidence-severity rating, comparable to those obtained for low erucic acid rapessed oil and soybean oil which were similar. Lowest lesion incidence was obtained with safflower oil and hydrogenated coconut oil. We have postulated that linolenic acid plays a role in the etiology of cardiac necrosis observed when rats are fed diets containing low erucic acid rapeseed oils.
TL;DR: The data indicate that, like rats fed EFA-deficient diets, dietary 18∵2 and 18∶3 exert a specific capacity to depress rat liver FAS and G6PD activities and rate of fatty acid synthesis.
Abstract: Dietary linoleate and linolenate were investigated for their ability to specifically inhibit liver and adipose tissue lipogenesis in meal-fed (access to food 900-1,200 hr), essential fatty acid (EFA) adequate rats. Supplementing a high carbohydrate diet containing 2.5% safflower oil with 3% palmitate 16∶0, oleate 18∶1, or linoleate 18∶2 did not affect in vivo liver or adipose tissue fatty acid synthesis. However, 18∶2 addition to the basal diet did result in a significant (P<0.05) decline of liver fatty acid synthetase (FAS) and glucose-6-phosphate dehydrogenase (G6PD) activities. When the safflower oil content of the basal diet was reduced to 1%, the addition of 3% 18∶2 or linolenate 18∶3 significantly (P<0.05) depressed hepatic FAS, G6PD, and in vivo fatty acid synthesis by 50%. Addition of 18∶1 caused no depression in hepatic FAS activity but did result in a significant (P<0.05) decline in liver G6PD activity and fatty acid synthesis which was intermediate between basal and basal +18∶2-or+18∶3-fed animals. Adipose tissue rates of lipogenesis were completely unaffected by dietary fatty acid supplementation. Similarly, the addition of 3 or 5% 18∶3 to a basal diet for only one meal resulted in no change in lipogenesis relative to that in animals fed the basal diet. The data indicate that, like rats fed EFA-deficient diets, dietary 18∶2 and 18∶3 exert a specific capacity to depress rat liver FAS and G6PD activities and rate of fatty acid synthesis.
TL;DR: Female rats have been fed high fat diets containing either polyunsaturated or saturated fat and some of the animals received an intragastric dose of 7,12-dimethylbenz(a)anthracene (DMBA), and the cumulative incidence of tumor-bearing rats among DMBA-dosed rats was greater when the polyuns saturated fat diet was fed.
Abstract: Female rats have been fed high fat diets containing either polyunsaturated or saturated fat. After being fed either of the diets for 4 weeks, some of the animals received an intragastric dose of 7,12-dimethylbenz(a)anthracene (DMBA). At this point, the diets of half of the animals were interchanged so that animals previously fed the polyunsaturated fat diet were fed the saturated fat diet and vice versa. The cumulative incidence of tumor-bearing rats among DMBA-dosed rats was greater when the polyunsaturated fat diet was fed. The mean induction time of tumors decreased and the proportion of tumor-bearing rats which developed malignant tumors increased when the polyunsaturated fat diet was fed. This promotional effect of the polyunsaturated fat diet was exerted only when the diet was fed after DMBA administration.
TL;DR: Two isoflavones, biochanin-A and formononetin isolated from gramCicer arietinum, have been shown to possess hypolipidemic properties for Triton WR-1339 induced hyperlipidemia in male albino rats, when administered as a crude extract or as individual compounds.
Abstract: Two isoflavones, biochanin-A and formononetin isolated from gramCicer arietinum, have been shown to possess hypolipidemic properties for Triton WR-1339 induced hyperlipidemia in male albino rats, when administered as a crude extract or as individual compounds.
TL;DR: Age- and strain-related differences in lipid metabolism of male Fisher 344 rats present an opportunity for a comparative study of the aging process using the parameters of lipid metabolism as indicators.
Abstract: Lipid metabolism of male Fisher 344 rats aged 2-24 months was studied. Serum and liver cholesterol levels did not display the age-related gradual increase seen in other rat strains. An increase in the serum plus liver cholesterol pool from 2 to 6 months was followed by a plateau through 18 months and then another increase at 24 months of age. The triglyceride pool increased from 2 to 6 months and then remained unchanged through 24 months of age. Cholesterol synthesis from acetate decreased 50% between 2 and 9 months and fell only slightly through 24 months of age. Assay of 3-hydroxy-3-methyl glutaryl Coenzyme A (HMG-CoA) reductase showed a similar pattern but did not decrease further after 9 months of age. Cholesterol 7alpha hydroxylase activity was not significantly altered by age. These age- and strain-related differences present an opportunity for a comparative study of the aging process using the parameters of lipid metabolism as indicators.
TL;DR: The increase in bis (monoacylglyceryl) phosphate (BMGP), which is peculiar to this kind of drug-induced lipidosis, was dependent upon the dose of the drug as well as the length of time.
Abstract: 4,4′-Bis (β-diethylaminoethoxy)-α,β-diethyldiphenylethane (DH), which had been shown to induce a type of lipidosis resembling Niemann-Pick disease, was given to rats at a dose of 20, 50, 100, and 150 mg/kg body weight per day for 1 or 2 weeks. An enlargement of the liver with marked increases in free cholesterol, total phospholipids, and phosphatidylinositol took place by administration of a larger dose. The increase in bis (monoacylglyceryl) phosphate (BMGP), which is peculiar to this kind of drug-induced lipidosis, was dependent upon the dose of the drug as well as the length of time. Similar changes were also observed in kidney. Among several other drugs tested, chloroquine and diazacholesterol brough on as much increase in BMGP as treatement with DH.
TL;DR: The data indicate that lamellar bodies are not the site of synthesis of the lipid component of pulmonary surfactant by pathways involving these enzymes.
Abstract: Palmitoyl CoA-glycerol-3-phosphate acyltransferase, phosphatidate phosphohydrolase, and phospholipase A were assayed in subcellular fractions of rat lung, including lamellar bodies, the putative site of storage and secretion of lung surfactant The specific activity of each of these enzymes in lamellar bodies was relatively low and could be entirely accounted for by a small contamination of the lamellar bodies fraction by microsomes, as quantitated by the presence of the microsomal marker reduced triphosphopyridine nucleotide cytochrome c reductase These data indicate that lamellar bodies are not the site of synthesis of the lipid component of pulmonary surfactant by pathways involving these enzymes
TL;DR: It is observed that addition of DEHP to a stock diet of rats resulted in marked effects on incorporation of14C-acetate into lipid by liver and kidney slices; other organs, such as heart, testes, and aorta were unaffected; the need for further biochemical studies to evaluate the effect of phthalates on biological systems is emphasized.
Abstract: Di-2-ethylhexyl phthalate (DEHP), a plasticizer commonly used in the production of polyvinyl chloride plastics, has become an environmental pollutant. At the present time, the biological significance of phthalates in the environment is unknown. In the present studies, we observed that addition of DEHP to a stock diet of rats resulted in marked effects on incorporation of 14C-acetate into lipid by liver and kidney slices; other organs, such as heart, testes, and aorta, were unaffected. Incorporation of 14C-acetate into total lipid of liver (dpm/mg wet wt) from rats fed 0.5% or 1.0% DEHP for 10 or 18 days, respectively, was decreased to ca. 50% of control values. The decreased incorporation into liver lipid is not attributable to any one lipid fraction, inasmuch as incorporation into the phospholipid, sterol + diglyceride, free fatty acid, triglyceride, and sterol ester + hydrocarbon fractions was decreased 30-70% with respect to controls. In addition, the percent distribution of 14C-acetate among the individual phospholipids was ca. 25% lower in phosphatidyl choline of the DEHP-fed rats. In rats fed 0.5% DEHP, incorporation of 14C-acetate into total lipid of kidney was similar to control values, but incorporation into the triglyceride and sterol ester + hydrocarbon fraction was decreased 30-40%, whereas incorporation into the sterol + diglyceride fraction was increased 38%. Livers from DEHP-fed rats were ca. 20% larger than livers from control rats and, at the 0.5% level of DEHP feeding, testes wts were elevated; no significant changes were noted in wts of spleen, heart, aorta, kidney, or body wt gains in rats fed DEHP. These studies emphasize a subtle toxicity of phthalate esters not previously reported and emphasize the need for further biochemical studies to evaluate the effect of phthalates on biological systems.
TL;DR: The results of this study indicate that the myocardial lesions associated with feeding 20% rapeseed oil diets are not related to the content of erucic acid per se and it is suggested that a triglyceride imbalance in the oil might play an important role in causing these lesions in rats.
Abstract: The back and belly fat of pigs fed a diet containing 20% by wt rapeseed oil (22% erucic acid) for 16 weeks was rendered into oil. This rendered pig fat, which contained 5.6% erucic acid, was fed to male rats in three separate experiments at 20% by wt of the diet for 16 weeks. In experiment I rendered pig fat was compared only toBrassica campestris var. Span rapeseed oil containing 4.8% erucic acid. In experiments II and III, rendered pig fat was compared to commerical lard containing 0.2% docosenoic acid, commercial lard to which 5.4% free erucic acid was added, and Span rapessed oil. There was no significant (P<0.01) differences observed in the level of erucic acid in the hearts of rats fed diets of rendered pig fat, Span rapeseed oil, or commercial lard plus erucic acid. However, the incidence (P<0.001) and severity (P<0.01) of cardiac lesions were significantly higher in Span rapeseed oil fed rats compared to rats fed control diets. The number of rats affected or the severity of lesions in the rendered pig fat fed group was not significantly different from controls. The results of this study indicate that the myocardial lesions associated with feeding 20% rapeseed oil diets are not related to the content of erucic acid per se. The possible reasons why rapeseed oil causes cardiac lesions in rats are discussed. It is suggested that a triglyceride imbalance in the oil might play an important role in causing these lesions in rats.
TL;DR: The results suggested that ovine adipose tissue lipogenesis is sensitive to both the amount and the nature of dietaryfat, as well as various enzymes thought to be involved in lipogenesis.
Abstract: The effects of different dietary fats on ovine adipose tissue metabolism have been investigated. Six-month old sheep were fed for 6 weeks a control diet or diets supplemented with either tallow or a mixture of sunflower seed oil and soybean oil, treated to protect the fats from hydrolysis and hydrogenation in the rumen, or with maize oil. The rates of fatty acid, glyceride glycerol, and CO2 formation were measured in perirenal and subcutaneous adipose tissue slices by following the incorporation of either14C from labeled acetate or glucose, or3H from tritiated water into the appropriate product. Feeding protected tallow or maize oil but not protected sunflower seed oil plus soybean oil resulted in reduced rates of fatty acid biosynthesis in both perirenal and subcutaneous adipose tissue slices and CO2 formation in perirenal adipose tissue. Feeding the fat-supplemented diets had no effect on the rate of glyceride glycerol formation. The fat-supplemented diets also resulted in reduced activities of various enzymes, thought to be involved in lipogenesis, measured in 105,000× g supernatant fractions from adipose tissue homogenates. The results suggested that ovine adipose tissue lipogenesis is sensitive to both the amount and the nature of dietary fat.
TL;DR: The present investigation has determined the sources of the cellular esterified cholesterol when the cells were grown in hyperlipemic serum and found that it was derived from exogenous (serum) cholesteryl esters.
Abstract: Previous investigations had demonstrated that Fu5AH rat hepatoma cells accumulated large quantities of esterified cholesterol when grown in hyperlipemic rabbit serum. The present investigation has determined the sources of the cellular esterified cholesterol when the cells were grown in hyperlipemic serum. Cellular esterification of endogenous and exogenous free cholesterol contributed 10% and 30%, respectively. The remaining 60% of the accumulated cellular esterfied cholesterol was derived from exogenous (serum) cholesteryl esters. Evidence for the hydrolysis of a portion of the incorporated esterified cholesterol is presented. A stimulation of free cholesterol incorporation and cellular esterification is elicited by hyperlipemic serum and serum lipoproteins when compared to normolipemic serum present at equivalent exogenous cholesterol concentrations. The effect of hyperlipemic serum is reduced by Tween-80 and Triton WR-1339. Comparative data on esterified cholesterol accumulation, free cholesterol incorporation, and cellular cholesterol esterification in Fu5-5 rat hepatoma cells, L-cells, and rabbit aortic medial cells are presented.