PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Lipid Peroxides”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1978

The role of lipid components of the diet in the regulation of the fatty acid composition of the rat liver endoplasmic reticulum and lipid peroxidation.

The fatty acid compositions of the lipids and the lipid peroxide concentrations and rates of lipid peroxidation were determined in suspensions of liver endoplasmic reticulum isolated from rats fed on synthetic diets in which the fatty acid composition had been varied but the remaining constituents (protein, carbohydrate, vitamins and minerals) kept constant. Stock diet and synthetic diets containing no fat, 10% corn oil, herring oil, coconut oil or lard were used. The fatty acid composition of the liver endoplasmic reticulum lipid was markedly dependent on the fatty acid composition of the dietary lipid. Feeding a herring-oil diet caused incorporation of 8.7% eicosapentaenoic acid (C(20:5)) and 17% docosahexaenoic acid (C(22:6)), but only 5.1% linoleic acid (C(18:2)) and 6.4% arachidonic acid (C(20:4)), feeding a corn-oil diet caused incorporation of 25.1% C(18:2), 17.8% C(20:4) and 2.5% C(22:6) fatty acids, and feeding a lard diet caused incorporation of 10.3% C(18:2), 13.5% C(20:4) and 4.3% C(22:6) fatty acids into the liver endoplasmic-reticulum lipids. Phenobarbitone injection (100mg/kg) decreased the incorporation of C(20:4) and C(22:6) fatty acids into the liver endoplasmic reticulum of rats fed on a lard, corn-oil or herring-oil diet. Microsomal lipid peroxide concentrations and rates of peroxidation in the presence of ascorbate depended on the nature and quantity of the polyunsaturated fatty acids in the diet. The lipid peroxide content was 1.82+/-0.30nmol of malonaldehyde/mg of protein and the rate of peroxidation was 0.60+/-0.08nmol of malonaldehyde/min per mg of protein after feeding a fat-free diet, and the values were increased to 20.80nmol of malonaldehyde/mg of protein and 3.73nmol of malonaldehyde/min per mg of protein after feeding a 10% herring-oil diet in which polyunsaturated fatty acids formed 24% of the total fatty acids. Addition of alpha-tocopherol to the diets (120mg/kg of diet) caused a very large decrease in the lipid peroxide concentration and rate of lipid peroxidation in the endoplasmic reticulum, but addition of the synthetic anti-oxidant 2,6-di-t-butyl-4-methylphenol to the diet (100mg/kg of diet) was ineffective. Treatment of the animals with phenobarbitone (1mg/ml of drinking water) caused a sharp fall in the rate of lipid peroxidation. It is concluded that the polyunsaturated fatty acid composition of the diet regulates the fatty acid composition of the liver endoplasmic reticulum, and this in turn is an important factor controlling the rate and extent of lipid peroxidation in vitro and possibly in vivo.

Animals↗
PubMed1979

[Effect of lecithin on liver microsomal lipid peroxidation].

The effect of exogeneous (egg) lecithin on peroxidation of microsomal lipids was studied with the view of elucidating the role of various components of lipid substrate in the overall oxidation rate of the lipids. The following processes were studied a) NADPH-dependent microsomal lipid peroxidation in the presence of lecithin; b) ascorbate-dependent microsomal lipid peroxidation in the presence of lecithin; c) oxidation of lipid mixture, isolated from the microsomes, and that of lecithin in the presence of the Fe2+ + ascorbate system; 4) oxidation of lecithin induced by the Fe2+ + ascorbate system. It was found that in the presence of exogeneous lecithin the oxidation of microsomal lipids in inhibited, which is probably due to the peculiarities of lecithin oxidation. It was shown that the specific rate of lecithin oxidation is decreased with an increase in lecithin concentration. Possible mechanisms of lecithin effect on microsomal lipid peroxidation are discussed.

Animals↗
PubMed1975

The consequences of lipid peroxidation in isolated hepatocytes.

Lipid peroxidation was initiated by the addition of either ADP-complexed Fe3+ or cumene hydroperoxide to isolated rat hepatocytes and the resultant biochemical and morphological alterations investigated. As previously observed with microsomes, malonaldehyde formation was associated with the inactivation of glucose-6-phosphatase. Inhibition of microsomal oxidative drug metabolism was correlated with the release and subsequent inactivation of NADPH-cytochrome c reductase, whereas cytochrome P-450 destruction occurred only in the presence of high concentrations of the organic hydroperoxide which were associated with extensive malonaldehyde formation. Under these conditions there were also marked ultrastructural alterations in the hepatocytes which were not apparent after incubation in the presence of iron (less than or equal to 187 muM Fe3+). The latter treatment was, however, associated with moderate biochemical effects such as glucose-6-phosphatase inactivation and increased membrane permeability. The cellular defence system against lipid peroxidation is discussed and it is concluded that the isolated liver cell system provides a valuable tool for the study of lipid peroxidation and its pathological implications.

Adenosine Diphosphate↗
PubMed1978

Immunochemical study on the pathway of electron flow in reduced nicotinamide adenine dinucleotide-dependent microsomal lipid peroxidation.

NADH could support the lipid peroxidation of rat liver microsomes in the presence of ferric ions chelated by ADP(ADP-Fe). The reaction had a broad pH optimum (pH 5.8--7.4) and was more active in the acidic pH range. Antibodies to NADH-cytochrome b5 reductase [EC 1.6.2.2] and cytochrome b5 inhibited NADH-dependent lipid peroxidation in the presence of ADP-Fe, whereas the antibody against NADPH-cytochrome c reductase [EC 1.6.2.4] showed no inhibition. These oberservations suggest that the electron from NADH was supplied to the lipid peroxidation reaction via NADH-cytochrome b5 reductase and cytochrome b5. On the other hand, NADPH-supported lipid peroxidation was strongly inhibited by the antibody against NADPH-cytochrome c reductase, confirming the participation of this this flavoprotein in the NADPH-dependent reaction. In the presence of both ADP-Fe and ferric ions chelated by EDTA(EDTA-Fe), NADH-dependent lipid peroxidation was highly stimulated up to the level of the NADPH-dependent reaction. In this case, the antibody against cytochrome b5 could not inhibit the reaction, while the antibody against NADH-cytochrome b5 reductase did inhibit it, suggesting the direct transfer of electrons from NADH-cytochrome b5 reductase to EDTA-Fe complex.

Animals↗
PubMed1992

Etofibrate treatment alters low density lipoprotein susceptibility to lipid peroxidation.

The effect of the lipid lowering drug etofibrate was investigated on lipid peroxidation as well as on cholesterol level. Rabbits were given a 0.1% cholesterol containing diet. Total cholesterol, LDL-cholesterol, triglycerides and lipid peroxidation, expressed as thiobarbituric acid reactive products, were determined. Treatment with etofibrate led to a marked decrease in total cholesterol and LDL-cholesterol. Furthermore, Cu(2+)-induced lipid peroxide formation was reduced in etofibrate treated rabbits. These results could be confirmed in a human study when patients with moderate hypercholesterolaemia were treated with etofibrate (2 x 500 mg/day) for a period of eight weeks. It could be shown that the onset of lipid peroxidation was remarkably increased, an effect which was completely reversible. Thus, etofibrate is effective not only in lowering plasma cholesterol but also in rendering LDL less susceptible to oxidation.

Animals↗
PubMed1977

Stimulative effects of chelating agents, 2,2'-bipyridine and 1,10-phenanthroline, on lipid peroxidation in rat liver microsomes.

Well known lipid peroxidation inhibitors, 1,10-phenanthroline and 2,2'-bipyridine, stimulated microsomal NADPH- and ascorbic acid-dependent lipid peroxidation when low concentrations of these chelating agents were added to incubation mixture. The stimulatory effects of the chelating agents on lipid peroxidation were enhanced when ferrous ion was added together with the chelating agents to the mixture at a molar ratio of 1:1. Ethylenediaminetetraacetic acid (EDTA) had no stimulatory effect on lipid peroxidation. Ferrous ion-EDTA complex increased lipid peroxidation by only 20-30%, which was lower than that obtained by addition of the same concentration of ferrous ion alone. On the other hand, manganese and calcium ions, which are also inhibitors of lipid peroxidation, had no ability to stimulate lipid peroxidation even in the presence of extra ferrous ions. Changes in the lipid peroxidation by chelating agents affected the apparent activity of ethylmorphine N-demethylation.

2,2'-Dipyridyl↗
PubMed1977

Studies on vitamin E and selenium deficiency in young pigs. II. The hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium status.

The usefulness of the hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium deficiency in swine has been evaluated. Results indicated that although the hydrogen peroxide hemolysis test may be of some indication of the vitamin E status, it is not a reliable index of vitamin E deficiency in swine, at least on an individual basis. In contrast, the measure of red cell lipid peroxides can be considered a reliable test for vitamin E deficiency in swine. The hydrogen peroxide hemolysis test and the red cell lipid peroxides were not significantly affected by selenium deficiency.

Animals↗
PubMed1992

Lipid peroxidation of liposome induced by glucosone.

Lipid peroxidation of liposome made of egg lecithin was induced by glucosone (D-arabino-hexos-2-ulose), a secondary product of Maillard reaction or glycation of protein. Lipid peroxidation was assessed with measurement of TBARS (thiobarbituric acid reacting substances), POV (peroxide value), and HPLC measurement of MDA (malondialdehyde). EDTA and DTPA (diethylenetriamine-pentaacetic acid) inhibited the lipid peroxidation assessed by each method described above, indicating involvement of metal ions. The observed reduction of Fe3+ to Fe2+ by glucosone might be a critical step of the lipid peroxidation. Our findings suggest a possible role of lipid peroxidation of low-density lipoproteins (LDL) induced by glucosone in atherosis caused by diabetes mellitus.

Chromatography, High Pressure Liquid↗
PubMed1975

Singlet oxygen production associated with enzyme-catalyzed lipid peroxidation in liver microsomes.

Evidence for the formation of singlet oxygen during the oxidation of NADPH by liver microsomes is presented. The evidence is based primarily on the enzyme-dependent formation of dibenzoylethylene from diphenylfuran, a reaction which is specific for singlet oxygen. The apparent formation of singlet oxygen is coupled to the occurrence of peroxidation of microsomal lipid, a phenomenon known to be associated with NADPH oxidation by the particles. Both the peroxidation of lipid and the apparent formation of singlet oxygen are related to the amount of Fe3+ present in the system and the results are consistent with the possibility that the singlet oxygen formed by this system is derived from the breakdown of lipid peroxides. If 1O2 is formed from breakdown of lipid peroxides, it would be dependent on O-/-2 formation because superoxide anion has been shown to undergo reactions in this system which generate extremely reactive free radicals (probably hydroxyl) that initiate lipid peroxidation. These peroxides are quite unstable and their degradation may be the source of 1O2. We have consistently observed that O-/-2 itself is not a reactive radical with respect to lipids or radical scavengers. Hence, O-/-2 cannot be the radical which initiates lipid peroxidation on which 1O2 generation appears to depend. The results may offer at least part of the explanation for the dietary requirement for alpha-tocopherol which not only scavenges free radicals but quenches singlet oxygen as well. This report also includes description of studies indicating that another enzyme, xanthine oxidase, which forms superoxide anion during its activity under aerobic conditions, does not form singlet oxygen during its function. This finding is in contrast to reports of others which indicate that xanthine oxidase activity does produce 1O2.

Aniline Compounds↗
PubMedDate not supplied

An inhibitor of lipid peroxidation in rat lungs.

Formation of lipid peroxides in vitro was investigated in the lung, liver, and brain homogenates of normal male rats. Unlike brain tissue, increasing the concentration of lung or liver in homogenates resulted in decreased output of lipid peroxides. Further, lung homogenates exerted an inhibition of lipid peroxide formation by brain and dilute liver homogenates. The factor responsible for such inhibition was located in the postmitochondrial supernatant, was heat stable, nondialysable, could be preserved in frozen state for 60 days, concentrated by dialysis against powdered sucrose, and precipitated by ammonium sulphate.

Ammonium Sulfate↗
PubMed1977

Adriamycin: the role of lipid peroxidation in cardiac toxicity and tumor response.

The antitumor antibiotic, adriamycin, induces severe cardiac toxicity associated with peroxidation of cardiac lipids in mice. Both this lipid peroxidation and cardiac toxicity of adriamycin are reduced by prior treatment of the animals with the free radical scavenger tocopherol. Such treatment with tocopherol does not, however, alter the magnitude or duration of the adriamycin-induced suppression of DNA synthesis in P388 ascites tumor, nor does it diminish the antitumor responsiveness of P388 ascites tumor. These results suggest that adriamycin has at least two mechanisms of tissue damage: one, which involves lipid peroxidation, is blocked by tocopherol and results in cardiac toxicity; the other, which involves binding to DNA, is not antagonized by tocopherol and is responsible for tumor response.

Animals↗
PubMed1975

Lipid peroxidation in human erythrocytes in tocopherol deficiency.

Lipid peroxidation following exposure to H2O2 vapour was abnormally great in the erythrocytes from certain patients with low plasma tocopherol concentrations. Following treatment of such patients with tocopherol, erythrocyte lipid peroxidation was markedly reduced. The in vitro addition of tocopherol reduced lipid peroxidation in erythrocytes from both normal subjects and tocopherol-deficient patients.

Aged↗
PubMed1976

Effect of glutathione peroxidase activity on lipid peroxidation in biological membranes.

Results are presented indicating that, although glutathione peroxidase activity inhibits lipid peroxidation in membranes, it does not appear to do so by reducing membrane lipid peroxides to lipid alcohols, as has been shown by others to be the case for free fatty acid peroxides in solution. Lipid peroxidation was studied in an enzymic system (microsomal NADPH oxidase) and in a non-enzymic system (mitochondria plus ascorbate). A study of the fatty acids in the phospholipids of microsomes and mitochondria demonstrated that detectable amounts of hydroxy fatty acids were not formed in the membranes when the latter were incubated in the presence of the glutathione peroxidase system even under conditions known to have generated significant levels of lipid peroxides in the membrane. Fatty acid analyses of the microsomal and mitochondrial particles indicated that glutathione peroxidase activity inhibited loss of polyunsaturated fatty acids when these organelles were exposed to peroxidizing conditions. If glutathione peroxidase activity were inhibiting the formation of malondialdehyde (a product of lipid peroxidation) by converting peroxide groups to alcohols, the loss of the constitutive polyunsaturated fatty acids in the membrane should not have been appreciably affected by addition of the peroxidase system. The protective effect cannot be due to quenching of an autocatalytic type of lipid peroxidation (at least in the microsomal system) since it has been established that the microsomal enzyme system (NADPH oxidase) catalyzes a continuous attack on microsomal polyunsaturated fatty acyl groups during the reaction and that the peroxidative process is not autocatalytic in nature. It appears, therefore, that glutathione peroxidase activity must exert its effect on this system by preventing free radical attack on the polyunsaturated membrane lipids in the first place. A possible mechanism for the interruption of a free radical attack on the lipids is proposed.

Animals↗
PubMed1975

Further studies on lipid-peroxide formation in isolated hepatocytes.

Lipid peroxide formation was initiated by the addition of either ADP-complexed Fe3+ or cumene hydroperoxide to a suspension of isolated hepatocytes. The reaction was monitored by malonaldehyde measurements. Upon the addition of iron, malonaldehyde production in the cells started immediately but ceased within 30-60 min, and the response was dose-related with iron concentrations ranging from 19 to 187 muM. Malonaldehyde formation was associated with increased oxygen uptake and conjugated diene production. The addition in vitro of N,N,N',N'-tetramethyl-p-phenylenediamine, menadione or p-benzoquinone inhibited the iron-induced malonaldehyde production. It was also possible to demonstrate an apparent disappearance of malonaldehyde from fresh cells by addition of adequate amounts of N,N,N',N'-tetramethyl-p-phenylenediamine (100 muM). The attenuation of the iron-induced malonaldehyde production was found to be correlated with an increased binding of iron to an intracellular ferritin fraction. Further, malonaldehyde formation was also associated with a conversion of reduced glutathione to the oxidized form which, in turn, revealed a faster permeation out of the cells into the surrounding medium of the oxidized than of the reduced thiol. So, concomitant with the redox alterations, there was also an overall loss of glutathione from the cells. Cumene hydroperoxide-induced malonaldehyde production could be initiated by the addition of this peroxide in concentrations ranging from 150 muM to the liver cell incubate. With concentrations below 150 muM, a lag phase was present which seemed to be glutathione-dependent. It is concluded that iron enters the cell, then is probably reduced inside the cell by NADPH via the NADPH-cytochrome P-450 reductase, and in the reduced state initiates lipid peroxidation. The reaction is inhibited by intracellular mechanisms, the glutathione redox system being of principal importance, and possibly terminated by the iron-apoferritin complex formation.

Adenosine Diphosphate↗
PubMedDate not supplied

[Alteration of lipid peroxidation of rat liver endoplasmic reticulum in the presence of steroid hormones].

Effect of steroid hormones on peroxidation of lipids of rats' liver endoplasmic reticulum was studied. Accumulation of peroxidation products was measured by the change in chemoluminescence intensity and by the rate of malone dealdehydeformation. It was shown that typical antioxidants--estrogenes were the inhibitors of NADH-H and ascorbate-dependent systems of lipid peroxidation in rat liver microsomes, the enzymatic system being the most sensitive one.

Animals↗
PubMed1979

Growth-related lipid peroxidation in tumour microsomal membranes and mitochondria.

Microsomes and mitochondria isolated from Morris hepatomas 3924A (fast-growing) and 44 (slow-growing) and Ehrlich ascites tumour cells exhibit a NADPH-dependent peroxidation of endogenous lipids lower than that of the corresponding fractions from rat liver. Moreover, the O2- and ascorbate-dependent lipid peroxidations are decreased in microsomes from the two Morris hepatomas. The peroxidative activity appears to be inversely related to the growth rate of the tumours. It is suggested that the low susceptibility of tumour membranes to peroxidative agents may be a factor responsible for the high mitotic activity of this tissue.

Animals↗
PubMedDate not supplied

[Effect of serotonin and malate benzyl hydrazine on glutathione peroxidase and lipid peroxidation by rat heart and liver mitochondria].

The effect of serotonin and malate benzyl hydrazine (inhibitor MAO) on the activity of glutathione peroxidase and intensity of ascorbate-dependent peroxidation of lipids in mitochondria was investigated. Serotonin injected intraperitoneally at a concentration of 20 m/kg increased activity of glutathione peroxidase in liver mitochondria and nonfermented ascorbate-dependent peroxidation of lipids in heart mitochondria. In experiments in vitro serotonin and malate benzyl hydrazine decreased activity of glutathione peroxidase an inhibited nonfermented ascorbate-dependent peroxidation in mitochondria of the heart and liver of rats.

Animals↗