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1.
The reasons why most cellular lipids preferentially accumulate 22:6(n-3) rather than 22:5(n-6) are poorly understood. In the present work the metabolisms of the precursor fatty acids, [1-(14)C]20:4(n-6), [1-(14)C]22:4(n-6) versus [1-(14)C]20:5(n-3), [1-(14)C]22:5(n-3) in isolated rat hepatocytes were compared. The addition of lactate and L-decanoylcarnitine increased the formation of [(14)C]24 fatty acid intermediates and the final products, [(14)C]22:5(n-6) and [(14)C]22:6(n-3). In the absence of lactate and L-decanoylcarnitine, no [(14)C]24 fatty acids and [(14)C]22:5(n-6) were detected when [1-(14)C]22:4(n-6) was the substrate, whereas small amounts of the added [1-(14)C]22:5(n-3) was converted to [(14)C]22:6(n-3). Lactate reduced the oxidation of [1-(14)C]22:4(n-6) and [1-(14)C]22:5(n-3) while L-decanoylcarnitine did not. No significant differences between the total oxidation or esterification of the two substrates were observed. By fasting and fructose refeeding the amounts of [(14)C]24:4(n-6) and [(14)C]24:5(n-3) were increased by 2.5- and 4-fold, respectively. However, the levels of [(14)C]22:5(n-6) and [(14)C]22:6(n-3) were similar in hepatocytes from fasted and refed versus fed rats. With hepatocytes from rats fed a fat free diet the levels of [(14)C]24 fatty acid intermediates were low while the further conversion of the n-6 and n-3 substrates was high and more equal, approx. 33% of [1-(14)C]22:4(n-6) was converted to [(14)C]22:5(n-6) and 43% of [1-(14)C]22:5(n-3) was converted to [(14)C]22:6(n-3). The moderate differences found in the conversion of [1-(14)C]22:4(n-6) versus [1-(14)C]22:5(n-3) to [(14)C]22:5(n-6) and [(14)C]22:6(n-3), respectively, and the equal rates of oxidation of the two substrates could thus not explain the abundance of 22:6(n-3) versus the near absence of 22:5(n-6) in cellular membranes. 相似文献
2.
Impairment of effects of vasopressin on [1-14C]oleate metabolism in hepatocytes from obese (ob/ob) mice. 总被引:2,自引:2,他引:0
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In hepatocytes from lean mice vasopressin decreased ketogenesis and increased 14CO2 production from [1-14C]oleate and glucose release; these effects were Ca2+-dependent. None of these effects of vasopressin were obtained with hepatocytes from obese (ob/ob) mice. Similarly, adrenaline did not increase 14CO2 production in these hepatocytes, but it stimulated glucose release. Possible reasons for the impairment of vasopressin action are discussed. 相似文献
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Metabolism of [1-14C]glyoxylate, [1-14C]-glycollate, [1-14C]glycine and [2-14C]-glycine by homogenates of kidney and liver tissue from hyperoxaluric and control subjects 总被引:1,自引:1,他引:0
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1. The metabolism of [1-(14)C]glyoxylate to carbon dioxide, glycine, oxalate, serine, formate and glycollate was investigated in hyperoxaluric and control subjects' kidney and liver tissue in vitro. 2. Only glycine and carbon dioxide became significantly labelled with (14)C, and this was less in the hyperoxaluric patients' kidney tissue than in the control tissue. 3. Liver did not show this difference. 4. The metabolism of [1-(14)C]glycollate was also studied in the liver tissue; glyoxylate formation was demonstrated and the formation of (14)CO(2) from this substrate was likewise unimpaired in the hyperoxaluric patients' liver tissue in these experiments. 5. Glycine was not metabolized by human kidney, liver or blood cells under the conditions used. 6. These observations show that glyoxylate metabolism by the kidney is impaired in primary hyperoxaluria. 相似文献
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V V Snitinski? V G Ianovich S I Vovk 《Zhurnal evoliutsionno? biokhimii i fiziologii》1985,21(1):86-88
Studies have been made on the intensity of oxidation of [U-14C]-palmitate, [1-14C]- and [6-14C]-glucose by slices of the liver and skeletal muscles of new-born, 1-day, 5-day and adult Wistar rats and domestic pigs. It was found that the level of 14CO2 production from these substrates is higher in tissues of rats than in those of pigs. At early stages of ontogenesis, in tissues of both species intensive oxidation of glucose is observed together with oxidation of fatty acids. In the course of ontogenetic development, the intensity of glucose utilization significantly decreases, whereas the level of fatty acid catabolism remains relatively unaffected. 相似文献
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Linlin Li Yinan Hua Maolong Dong Quan Li Derek T. Smith Ming Yuan Kyla R. Jones Jun Ren 《Obesity (Silver Spring, Md.)》2012,20(11):2174-2185
Lenalidomide is a potent immunomodulatory agent capable of downregulating proinflammatory cytokines such as tumor necrosis factor‐α (TNF‐α) and upregulating anti‐inflammatory cytokines. Lenalidomide has been shown to elicit cardiovascular effects, although its impact on cardiac function remains obscure. This study was designed to examine the effect of lenalidomide on cardiac contractile function in ob/ob obese mice. C57BL lean and ob/ob obese mice were given lenalidomide (50 mg/kg/day, p.o.) for 3 days. Body fat composition was assessed by dual‐energy X‐ray absorptiometry. Cardiomyocyte contractile and intracellular Ca2+ properties were evaluated. Expression of TNF‐α, interleukin‐6 (IL‐6), Fas, Fas ligand (FasL), the short‐chain fatty acid receptor GPR41, the NFκB regulator IκB, endoplasmic reticulum (ER) stress, the apoptotic protein markers Bax, Bcl‐2, caspase‐8, tBid, cytosolic cytochrome C, and caspase‐12; and the stress signaling molecules p38 and extracellular signal‐regulated kinase (ERK) were evaluated by western blot. ob/ob mice displayed elevated serum TNF‐α and IL‐6 levels, fat composition and glucose intolerance, the effects of which except glucose intolerance and fat composition were attenuated by lenalidomide. Cardiomyocytes from ob/ob mice exhibited depressed peak shortening (PS) and maximal velocity of shortening/relengthening, prolonged time‐to‐PS and time‐to‐90% relengthening as well as intracellular Ca2+ mishandling, which were ablated by lenalidomide. Western blot analysis revealed elevated levels of TNF‐α, IL‐6, Fas, Bip, Bax, caspase‐8, tBid, cleaved caspase‐3 caspase‐12, cytochrome C, phosphorylation of p38, and ERK in ob/ob mouse hearts, the effects of which with the exception of Bip, Bax, and caspase‐12 were alleviated by lenalidomide. Taken together, these data suggest that lenalidomide is protective against obesity‐induced cardiomyopathy possibly through antagonism of cytokine/Fas‐induced activation of stress signaling and apoptosis. 相似文献
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Loreau O Maret A Poullain D Chardigny JM Sébédio JL Beaufrère B Noël JP 《Chemistry and physics of lipids》2000,106(1):65-78
Several grams of labelled trans linoleic and linolenic acids with high chemical and isomeric purities (>97%) have been prepared for human metabolism studies. A total of 12.5 g of (9Z, 12E)-[1-(13)C]-octadeca-9,12-dienoic acid and 6.3 g of (9Z,12Z, 15E)-[1-(13)C]-octadeca-9,12,15-trienoic acid were obtained in, respectively, seven steps (7.8% overall yield) and 11 steps (7% overall yield) from 7-bromo-heptan-1-ol. The trans bromo precursors used for the labelling were synthesised by using copper-catalysed couplings. The trans fatty acids were then obtained via the nitrile derivatives. A total of 23.5 g of (9Z,12Z)-[1-(13)C]-octadeca-9, 12-dienoic acid and 10.4 g of (9Z,12Z,15Z)-[1-(13)C]-octadeca-9,12, 15-trienoic acid were prepared in five steps in, respectively, 32 and 18% overall yield. Large quantities of bromo and chloro precursors were synthesised from the commercially available acid according to Barton's procedure. In all cases, the main impurities (>0.5%) of each labelled fatty acid have been characterised. 相似文献
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N M Gula O O Mel'nyk M V Vysots'ky? D I Balkov G L Volkov N M Govseieva 《Ukrainski? biokhimicheski? zhurnal》1991,63(2):115-119
Distribution in dynamics of [1-14C]N-palmitoyl ethanolamine in the subcellular fractions of neuroblastoma C1300 N18 has been studied. It is shown that distribution dynamics of the label is different depending on subcellular fractions. The level of the label in cytoplasm 15 min after incubation reaches the value which remains constant till the end of the experiment. In the microsomal fraction the label is accumulated with time and becomes maximum at the end of the experiment. The highest amount of the label in the plasma membrane has been found 15 min later and then its amount falls. Parallel with this the amount of free fatty acids grows and then begins to fall simultaneously with an increase of the amount of esterified fatty acids. A considerable amount of the label of fatty acids has been determined 15 min later in the composition of di- and triglycerides of cytosol and microsomal fraction. 相似文献
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Thomas K. Schaff J.J. Plattner Donald L. Bussolotti 《Prostaglandins & other lipid mediators》1982,24(3):331-339
The synthesis of N-methanesulfonyl 16-phenoxy-ω-tetranor PGE2 carboxamide (sulprostone — CP-34,089/ZK-57,671) labeled with tritium and carbon-14 is described. Sulprostone labeled with tritium in the phenoxy moiety by means of catalytic hydrogenolysis was obtained in a 17% radiochemical yield with a specific activity of 1.0 Ci/mmol. The methanesulfonamide-14C derivative of sulprostone was prepared from methyl-14C iodide in an 11.8% radiochemical yield having a specific activity of 18.8 mCi/mmol. 相似文献
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Slices of ripening seeds of the pea (Pisum sativum) were suppliedwith [1-14C] G and [6-14C] G, and the S.A. was determined ofthe respirod carbon dioxide, pyruvate, and the acids of theT.C.A.C. as well as that of the individual carbon atoms of citrateand malate. The possibility that there exist active and inactive pools ofthe T.C.A.C. acids in the pea is considered and, for most ofthe acids, rejected. The results cannot be explained on the bais of the T.C.A.C.because the S.A. of the carbon dioxide liberated was some tentimes higher than could have come from the malate via the T.C.A.C.,too much 14C accumulated in the cycle acids to have come frompyruvate by the operation of the T.C.A.C., and the patterrnof label in citrate and malate was different from that expected. An alternative explanation is put forward based on the oxidationof glucose by the P.P.P. and movement of 14C by a series ofrapid isotope exchange reactions. 相似文献
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M J Garson V Partali S Liaaen-Jensen I L Stoilov 《Comparative biochemistry and physiology. B, Comparative biochemistry》1988,91(2):293-300
1. We present quantitative evidence from incorporation of [1-14C] acetate that the enzymes to synthesise isoprenoids are present in the marine sponge Amphimedon sp. and that efficient carotenoid synthesis takes place. 2. The de novo synthesis of b,b-carotene and (3R,3'R)-zeaxanthin may occur in a chlorophyll a-producing microalgal symbiont with subsequent aromatisation to (3R)-isoagelaxanthin by the sponge itself. 3. Amphimedon sp. contains nuclear-modified sterols derived by modification of conventional dietary sterols. 相似文献
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The acute immobilized stress was studied for its effect on oxidation rate of [1-14C]palmitoyl-CoA, [1-14C]acetyl-CoA and [2-14C]pyruvate in mitochondria of the adrenals, liver and heart of rabbits. The stress effect on the energy metabolism of adrenals is associated with an increase of the rate of CO2 formation from pyruvate and with a decrease of the rate of CO2 formation from palmitoyl-CoA. Intensified oxidation of all substrates is observed in the heart mitochondria. The processes of beta-oxidation are more active in the liver. The data obtained evidence for differences in the mechanisms of energy metabolism reconstruction under acute stress in tissues with different functional specialization. 相似文献
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Ogbunude PO 《Analytical biochemistry》2002,300(2):267-269
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Chun-Mei Zhang Min Zhang Jin-Gai Zhu Chen-Bo Ji Chun Zhu Chun-Zhao Kou Da-Ni Qin Mei-Ling Tong Xi-Rong Guo 《Journal of bioenergetics and biomembranes》2010,42(3):255-259
Uncoupling proteins (UCPs) located in the inner mitochondrial membrane are involved in the regulation of energy balance. Thus
far, 5 UCP isoforms have been identified, but controversies exist in the research focused on the function of the UCPs (except
UCP1) in the pathogenesis of obesity. Because of the known cross-reactivity of the antibodies presently available for the
detection of UCP proteins, this study systematically analyzed the differential tissue expression profiles of the 5 UCP isoforms
in lean control mice and ob/ob mice by using real-time polymerase chain reaction (PCR) analysis. The results show that the
tissue-specific expression patterns of individual isoforms in normal and ob/ob mice are considerably different; this will
provide new insights into the functions of UCPs in the pathogenesis of genetic obesity. 相似文献
19.
Stearoyl[1-14C]sulfogalactosylsphingosine ([14C]sulfatide) as substrate for cerebroside sulfatase assay 总被引:3,自引:0,他引:3
A convenient method for large scale preparation of stearoyl[1-14C]sulfogalactosylsphingosine has been developed. The first step consists in preparing the lysosulfatide intermediate with a good yield, which we have successfully performed. In the second step, the lysoderivative is coupled to [1-14C]stearic acid through the acyl chloride procedure. The labeled substrate thus synthetized appears to be particularly convenient for cerebroside sulfatase determination, because of the stability of the 14C isotope, compared to the other isotopes (tritium or 35S) which have been previously used for the same purpose. 相似文献
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