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PubMed1987

3-Methylindole inhibits lipid peroxidation.

The mechanism of pneumotoxicity of 3-methylindole has been postulated to occur via protein alkylation or lipid peroxidation. This report describes the effects of the addition of 3-methylindole to goat lung microsomes to evaluate the possibility that this xenobiotic may increase NADPH-supported lipid peroxidation. Concentrations of malondialdehyde were measured as an index of lipid peroxidation. Instead of a stimulation of lipid peroxidation by 3-methylindole, a complete inhibition of lipid peroxidation was produced by concentrations of 3-methylindole as low as 10 microM. The addition of 3-methylindole to actively peroxidizing microsomes (NADPH-supported) caused an immediate cessation of malondialdehyde production. These results demonstrate that 3-methylindole pneumotoxicity does not proceed by a mechanism of lipid peroxidation, but in fact, this molecule may act as an effective antioxidant to prevent lipid peroxidation in pulmonary tissue.

Animals↗

PubMed1982

Evidence for carbon tetrachloride-induced lipid peroxidation in mouse liver.

The involvement of lipid peroxidation in the mechanism of carbon tetrachloride-induced hepatotoxicity has been a point of controversy. Previous investigators have reported an absence of lipid peroxidative degradation products in mice after exposure to carbon tetrachloride and have used this evidence against the hypothesis that lipid peroxidation is an integral part of the events that cause tissue damage. We have compared the extent of lipid peroxidation caused by carbon tetrachloride between Sprague-Dawley rats and three strains of mice (A/J, BALB/cJ, and C57B1/6J) in in vitro and in vivo systems. Hepatic microsomes isolated from fasted mice of each strain produced more malondialdehyde (a degradation product of lipid peroxidation) per mg microsomal protein than those isolated from fasted rats at times of incubation with CCl4. In vivo lipid peroxidation was estimated by the lipid conjugated diene content in hepatic microsomes from the rat and three strains of mice. Increased conjugated diene formation was observed in microsomal lipids of these animals after intraperitoneal injection of CCl4 (1 ml/kg as a 20% solution in corn oil) when compared to animals given only corn oil, but no differences were found in the amount of conjugated dienes between mice and rats. Our observations show that the CCl4-treated mouse undergoes hepatic lipid peroxidation at least as well as the rat, and indicate that lipid peroxidation cannot be excluded as a mechanism of carbon tetrachloride hepatotoxicity as has been claimed on the basis of its ineffectiveness in the mouse.

Animals↗

PubMed1984

Influence of vitamin E and selenium on glutathione-dependent protection against microsomal lipid peroxidation.

A GSH-dependent microsomal protein which inhibits lipid peroxidation has been described [R. F. Burk, Biochim. biophys. Acta 757, 21 (1983)]. Studies of its mechanism indicate that it scavenges free radicals. Vitamin E (alpha-tocopherol) and selenium are micronutrients which protect against lipid peroxidation. The effect of nutritional deficiencies of these substances on the GSH-dependent protection against rat liver microsomal lipid peroxidation was studied to determine whether GSH, selenium and alpha-tocopherol function through separate or shared mechanisms. In the ascorbate-iron microsomal lipid peroxidation system, there is a 1-3 min lag phase before lipid peroxidation begins. The length of the lag correlated well (r = 0.87) with the microsomal alpha-tocopherol content as measured by high pressure liquid chromatography. Thus, the selenium-deficient microsomes, which had a shorter lag than controls, had a somewhat lower alpha-tocopherol content. The vitamin E-deficient microsomes, which had no detectable alpha-tocopherol, had the shortest lag, but a distinct lag was present. Addition of 0.1 mM GSH to control microsomes prolonged the lag by 270%. In selenium-deficient and vitamin E-deficient microsomes, which had shorter initial lags, GSH addition caused 345 and 280% increases respectively. This suggests that the function of the GSH-dependent protective mechanism is unimpaired in these deficiencies. Trypsin digestion of microsomes, which abolished the lag completely and destroyed the GSH-dependent protection, had no effect on microsomal alpha-tocopherol content, however. These experiments illustrate the importance of two defenses against microsomal lipid peroxidation: the GSH-dependent protein which is responsible for the existence of the lag, and alpha-tocopherol which affects the length of the lag. They suggest that these defenses function separately to prevent peroxidation of membrane polyunsaturated fatty acids. Selenium appears to affect microsomal alpha-tocopherol content but to have no other effect on the microsomal lipid peroxidation system.

Animals↗

PubMed1988

Intervention in free radical mediated hepatotoxicity and lipid peroxidation by indole-3-carbinol.

The cytoprotective effect of the natural dietary constituent indole-3-carbinol (I-3-C) on carbon tetrachloride (CCl4) mediated hepatotoxicity in mice was examined. I-3-C pretreatment by gavage 1 hr prior to intraperitoneal injection of CCl4 produced a 63% decrease in CCl4-mediated centrolobular necrosis and a related 60% decrease in plasma alanine aminotransferase activity (a marker of liver necrosis). Since the toxicological effects of CCl4 are mediated by radical species generated during reductive metabolism by cytochrome P-450, we examined the potential ability of I-3-C to scavenge reactive radicals. Three systems were used to evaluate the ability of I-3-C to intervene in free radical mediated lipid peroxidation. These systems consisted of the following: (1) phospholipid dissolved in chlorobenzene, with peroxidation initiated by the thermal and photo decomposition of azobisisobutyronitrile (AIBN); (2) sonicated phospholipid vesicles in phosphate buffer (pH 7.4), with peroxidation initiated by ferrous/ascorbate; and (3) mouse liver microsomes containing an NADPH-regenerating system, with peroxidation initiated with CCl4. Lipid peroxidation was measured in these three systems as thiobarbiturate-reacting material. In the AIBN and ferrous/ascorbate systems, I-3-C inhibited lipid peroxidation, with greater inhibition under conditions of low rates of free radical generation. I-3-C was not as effective an antioxidant as butylated hydroxytoluene (BHT) or tocopherol, but it inhibited peroxidation in a dose-response manner. I-3-C was most effective as a radical scavenger in the microsomal CCl4-initiated system by inhibiting lipid peroxidation in a dose-dependent fashion, with 50% inhibition at 35-40 microM I-3-C. This concentration is about one-third of the concentration of I-3-C achieved in liver after treatment of mice by gavage with 50 mg I-3-C/kg body weight. These data suggest that I-3-C may be a natural antioxidant in the human diet and, as such, may intervene in toxicological or carcinogenic processes that are mediated by radical mechanisms.

Animals↗

PubMed1989

Effect of thiols on lipid peroxidation in rat liver microsomes.

The stimulatory or inhibitory effects of various thiol compounds on in vitro lipid peroxidation by iron-ascorbate in rat liver microsomes were determined. Glutathione had no measurable pro-oxidant capacity, in contrast, it protected against lipid peroxidation. N-Acetyl l-cysteine and S-methyl-glutathione had no effect on in vitro lipid peroxidation. l-Cysteine stimulated lipid peroxidation and also of d-penicillamine and dl-dithiothreitol the pre-oxidant capacity predominated the anti-oxidant capacity. Cysteamine afforded a pronounced protection against in vitro lipid peroxidation. In contrast to the labile character of the glutathione dependent protection, the protection by cysteamine was not affected by heat-pretreatment of the liver microsomes or alkylating protein sulfhydryl groups by N-ethyl maleimide. Again in contrast to glutathione, the protection against in vitro microsomal lipid peroxidation by cysteamine was not reduced after in vivo lipid peroxidation induced by CC14. This suggests that even after the process of lipid peroxidation has been started, administration of cysteamine might still be beneficial.

Acetylcysteine↗

PubMed1989

The role of iron in oxygen radical mediated lipid peroxidation.

The role of iron in the peroxidation of polyunsaturated fatty acids is reviewed, especially with respect to the involvement of oxygen radicals. The hydroxyl radical can be generated by a superoxide-driven Haber-Weiss reaction or by Fenton's reaction; and the hydroxyl radical can initiate lipid peroxidation. However, lipid peroxidation is frequently insensitive to hydroxyl radical scavengers or superoxide dismutase. We propose that the hydroxyl radical may not be involved in the peroxidation of membrane lipids, but instead lipid peroxidation requires both Fe2+ and Fe3+. The inability of superoxide dismutase to affect lipid peroxidation can be explained by the fact that the direct reduction of iron can occur, exemplified by rat liver microsomal NADPH-dependent lipid peroxidation. Catalase can be stimulatory, inhibitory or without affect because H2O2 may oxidize some Fe2+ to form the required Fe3+, or, alternatively, excess H2O2 may inhibit by excessive oxidation of the Fe2+. In an analogous manner reductants can form the initiating complex by reduction of Fe3+, but complete reduction would inhibit lipid peroxidation. All of these redox reactions would be influenced by iron chelation.

Animals↗

PubMed1991

Excessive dietary tryptophan enhances plasma lipid peroxidation in rats.

High plasma cholesterol levels and plasma lipid peroxidation are associated with atherosclerosis. The effect of excessive dietary tryptophan on plasma lipid peroxidation was studied in rats fed a diet containing soybean oil (control), as well as an atherogenic diet, containing coconut oil and cholesterol. Feeding the atherogenic diet resulted in a 5-fold increment in plasma cholesterol concentration with no significant effect of the tryptophan supplementation. The plasma obtained from the hypercholesterolemic rats exhibited a 67% increased lipid oxidation (measured as thiobarbituric acid reactive substances) in comparison to normocholesterolemic plasma. Dietary tryptophan supplementation increased plasma lipid peroxidation by 9 and 21% in the control and in the hypercholesterolemic animals, respectively. Similarly, the excessive dietary tryptophan enhanced macrophage cholesterol esterification rate by 40 and 38% following cell incubation with the plasma obtained from the control and from the hypercholesterolemic animals, respectively. Since tryptophan is the precursor of serotonin we have measured urine concentration of 5-hydroxyindoleacetic acid (5HIAA), the metabolite of serotonin, and found 22 and 118% elevation in 5HIAA in the tryptophan fed control and hypercholesterolemic rats, respectively. The direct effect of tryptophan and serotonin on in vitro lipid peroxidation was also studied. Low density lipoprotein (LDL) was peroxidized by incubation with copper ions in the presence of tryptophan or serotonin. Serotonin was shown to enhance LDL peroxidation whereas tryptophan had no effect on LDL peroxidation. We conclude that excessive dietary tryptophan may be atherogenic since it enhanced plasma lipid peroxidation in hypercholesterolemic rats and increased macrophage uptake of plasma cholesterol. These effects are probably associated with increased plasma concentration of serotonin following the consumption of a tryptophan supplemented diet.

Animals↗

PubMed1986

Attenuation by prostacyclin of adrenaline-stimulated lipid peroxidation in the myocardium.

The study aimed to investigate the effect of adrenaline upon lipid peroxidation processes in the myocardium and to evaluate the effect of prostacyclin upon the content of lipid peroxidation products in adrenaline-treated hearts. Anaesthetized rabbits were infused for 2 hours with adrenaline /1 microgram/kg/min/, adrenaline and prostacyclin /2 ng/kg/min/ and prostacyclin alone; controls received saline. After termination of infusion lipid peroxidation products /conjugated double bonds CDB, malondialdehyde MDA, lipid-soluble fluorescent material, FM/ and SH groups were measured in the myocardial tissue. Adrenaline significantly increased the content of all three indices of lipid peroxidation and decreased the concentration of soluble SH groups. PGI2 infused simultaneously significantly decreased the concentration of final metabolites of peroxidation /MDA, FM/ and prevented decrease of SH groups. The content of intermediate products of peroxidation, CDB was elevated. In conclusion, enhanced free radical activity, resulting in increased peroxidation of myocardial lipids may contribute to known injurious effect of adrenaline upon myocardium. The finding that PGI2 prevents increased formation of final peroxidation products gives support for the hypothesis that anti-free radical activity may be a component of cytoprotective action of prostacyclin.

Animals↗

PubMed1996

Inhibition of lipid peroxidation by estradiol and 2-hydroxyestradiol.

We investigated the inhibition mechanism of lipid peroxidation by estrogens. Estradiol and 2-hydroxyestradiol showed strong inhibitory activities toward NADPH and ADP-Fe(3+)-dependent lipid peroxidations in the microsomes from rat livers only when the steroids were added to the reaction system before the start of the peroxidation reaction. These steroids also strongly inhibited oxygen uptake only when added before the start of the reaction. These results suggest that estradiol and 2-hydroxyestradiol inhibit the initial stage of microsomal lipid peroxidation. Lipid peroxidation of erythrocyte membranes induced by the systems of xanthine oxidase-hypoxanthine and ascorbate was strongly inhibited by 2-hydroxyestradiol, but not by estradiol. Lipid peroxidation of erythrocyte membranes induced by 2.2'-azobis- (amidinopropane) dihydrochloride was not markedly inhibited by estradiol and 2-hydroxyestradiol, suggesting that the steroids have low reactivity with lipid peroxyl radicals. However, lipid peroxidation induced by t-butyl hydroperoxide-Fe3+ was strongly inhibited only by 2-hydroxyestradiol. It seems that 2-hydroxyestradiol may interact with alkoxyl rather than with peroxyl radicals during lipid peroxidation.

Adenosine Diphosphate↗

PubMed1994

Developmental changes in the peroxidation potential of rat brain homogenate and mitochondria.

Lipid peroxidation, one of the most common expressions of oxidative stress, may be altered during normal physiological states including development. We have examined the changes in lipid peroxidation in rat brain, a tissue highly susceptible to oxidative damage, during this physiological state. In vivo lipid peroxidation was moderate in the foetal and neonatal period and increased during the postnatal development. Lipid peroxidation potential in brain homogenate and mitochondria, in Tris-HCl buffer or with exogenous cofactors, such as ascorbate-Fe2+, NADPH ADP-Fe3+ and cumene hydroperoxide, showed significant changes during pre- and postnatal development. In general, brain as well as liver (used as a standard tissue for comparison) seem to have low peroxidation potential in the foetal and neonatal period which then increases at different rates during development to reach adult values at different days. The low peroxidation potential corresponds to the rapid phase of cell proliferation. These results taken together with similar earlier finding in other systems may indicate a possible occurrence of a 'permissible period' during which the low levels of lipid peroxidation may be able to yield only low amounts of cytostatic aldehydes and peroxides as byproducts, thereby allowing rapid proliferation of cells.

Animals↗

PubMed1987

Electron paramagnetic resonance and spectrophotometric studies of the peroxide compounds of manganese-substituted horseradish peroxidase, cytochrome-c peroxidase and manganese-porphyrin model complexes.

Peroxide compounds of manganese protoporphyrin IX and its complexes with apo-horseradish peroxidase and apocytochrome-c peroxidase were characterized by electronic absorption and electron paramagnetic resonance spectroscopies. An intermediate formed upon titration of Mn(III)-horseradish peroxidase with hydrogen peroxide exhibited a new electron paramagnetic resonance absorption at g = 5.23 with a definite six-lined 55Mn hyperfine (AMn = 8.2 mT). Neither a porphyrin pi-cation radical nor any other radical in the apoprotein moiety could be observed. The reduced form of Mn-horseradish peroxidase, Mn(II)-horseradish peroxidase, reacted with a stoichiometric amount of hydrogen peroxide to form a peroxide compound whose electronic absorption spectrum was identical with that formed from Mn(III)-horseradish peroxidase. The electronic state of the peroxide compound of manganese horseradish peroxidase was thus concluded to be Mn(IV), S = 3/2. Mn(III)-cytochrome-c peroxidase reacted with stoichiometry quantities of hydrogen peroxide to form a catalytically active intermediate. The electronic absorption spectrum was very similar to that of a higher oxidation state of manganese porphyrin, Mn(V). Since the peroxide compound of manganese cytochrome-c peroxidase retained two oxidizing equivalents per mol of the enzyme (Yonetani, T. and Asakura, T. (1969) J. Biol. Chem. 244, 4580-4588), this peroxide compound might contain an Mn(V) center.

Cytochrome-c Peroxidase↗

PubMed1993

Iron/ascorbate-induced lipid peroxidation changes membrane fluidity and muscarinic cholinergic receptor binding in rat frontal cortex.

Lipid peroxidation (LP) is a complex process which involves the formation of lipid free radicals and leads to oxidative damage. LP has also been implicated in several neurodegenerative diseases as well as aging. In the present study, we evaluated the effects of the induction of LP in vitro on muscarinic cholinergic (Mch) receptor binding and membrane fluidity in rat brain. Membranes from the rat frontal cortex were peroxidized by adding ferrous sulphate (84 microM) and ascorbic acid (400 microM). Peroxidation was measured as the amount of thiobarbituric acid reactive products formed (nmol malondialdehyde/mg protein). Mch receptor binding was measured 10, 20 and 30 min after peroxidation. Membrane fluidity was evaluated by fluorescence polarization studies using two probes; 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-[4(trimethylamino)phenyl]-1,3,5-hexatriene (TMA-DPH). Significant alterations in Mch receptor binding (decreased Bmax and increased Kd) were found after peroxidation. Membrane fluidity was also significantly decreased after peroxidation as observed with both probes. The decrease in membrane fluidity was due to an increased cholesterol to phospholipid molar ratio after peroxidation. These data suggest that lipid peroxidation induces changes in membrane dynamics as detected by the fluorescent probes and such changes in membrane microviscosity may be the cause for alterations in Mch receptor kinetics.

Animals↗

PubMed1995

Influence of lipid peroxidation on [3H]ketanserin binding to 5-HT2 prefrontal cortex receptors.

The influence of lipid peroxidation on 5-HT2 receptor binding was examined in prefrontal cortex membranes from sheep brain. Lipid peroxidation was induced with ascorbic acid and ferrous sulphate and measured by the thiobarbituric acid method. In lipid-peroxidized membranes, [3H]ketanserin specific binding was inhibited. The Bmax values decreased by 80%, from 50.1 +/- 3.5 fmol/mg protein in control membranes to 10.1 +/- 2.0 fmol/mg protein in peroxidized membranes, indicating a decrease in the number of 5-HT2 binding sites. However, the KD values for the [3H]ketanserin specific binding did not significantly change. In order to further characterize [3H]ketanserin binding, the inhibition potency (IC50 values) of antagonists or agonists of serotonin and dopamine receptors for [3H]ketanserin specific binding was determined. In control membranes, the order of inhibition potency of the drugs tested was the following: ketanserin (-log[IC50]=8.56 +/- 0.70] > ritanserin (-log [IC50]=8.13 +/- 0.30)>methysergide (-log[IC50]= 7.42 +/- 0.50)> spiperone (-log[IC50]=7.23 +/- 0.18 > serotonin (-log [IC50] = 6.99 +/- 0.65)> haloperidol (-log[IC50]= 6.95 +/- 0.65) > dopamine (-log [IC50] = 5.82 +/- 0.76). After membrane lipid peroxidation, the IC50 value for ritanserin was significantly increased, suggesting a decreased capacity for displacing [3H]ketanserin specific binding. Other antagonists of 5-HT2 receptors showed apparent increases in IC50 values upon peroxidation, whereas spiperone was shown to be the most potent drug (-log[IC50]= 7.19 +/- 1.06) in inhibiting [3H]ketanserin specific binding. A decrease in polyunsaturated fatty acids, namely docosahexaenoic acid (22:6) was also observed in peroxidized membranes. These results indicate a modulating role of the surrounding lipids and of the physical properties of the membranes on the binding activity of 5-HT2 receptors upon the lipid peroxidation process, which can be involved in the tissue impairment that occurs during the aging process and in post-ischemic situations.

Animals↗

PubMed1990

Analysis of hydrogen peroxide in freshly prepared coffees.

Coffee has been shown unequivocally to be genotoxic in vitro, but no genotoxicity has been seen in vivo testing. Since the in vitro genotoxicity appears to be dependent on hydrogen peroxide, it is important to know whether hydrogen peroxide is present in prepared coffee and whether it is being formed during the in vitro testing. We have devised a procedure to measure hydrogen peroxide in prepared coffee using disposable reversed-phase columns to decolourize the coffee and retain its catechols. Hydrogen peroxide was assayed in the eluate from the columns by two chromogenic methods: horseradish-peroxidase-mediated oxidation of phenol red and non-enzymatic oxidation of iodide. Three brands of brewed and instant coffee prepared in the manner recommended to the consumer were studied. Although six of the twelve preparations of coffee contained 3-29 microM-hydrogen peroxide, in the other six none could be detected. Sampling, batch, and aging effects may contribute to the variability in the testing, but there is no indication of greater than 100 microM-hydrogen peroxide levels in freshly prepared coffees, as reported in the literature using other methods. Hydrogen peroxide did form slowly in prepared coffee as the beverage became oxygenated, but it formed quickly if the coffee was diluted by addition to an oxygen-containing solution at neutral pH and then incubated at 37 degrees C. These results strongly suggest that adventitious formation of hydrogen peroxide is a confounding factor in the analytical and in vitro genotoxicological testing of coffees.

Beverages↗

PubMed1993

Modification of NMDA receptor by in vitro lipid peroxidation in fetal guinea pig brain.

The effect of lipid peroxidation on the NMDA receptor and its modulatory sites in fetal guinea pig brain cell membranes was examined. P2 membrane fractions were prepared from the fetal brain tissue and peroxidized in the presence of ferric chloride and ascorbate. [3H]-MK-801-binding studies were performed and Bmax (number of binding sites) and Kd (affinity) values were used as indices of NMDA receptor modification. In lipid-peroxidized membranes the Kd value increased from 6.76 +/- 2.69 in control to 15.12 +/- 7.38 nM (P < 0.01), indicating a decreased affinity of NMDA receptors following lipid peroxidation. However, there was no significant change in Bmax. The glutamate- and glycine-dependent increase in activation was 40% lower in lipid-peroxidized membranes as compared to control. The spermine-dependent activation was also significantly reduced following lipid peroxidation as compared to control suggesting decreased affinity of spermine site. The results of this study indicate that lipid peroxidation modifies recognition, coactivator and spermine sites of NMDA receptor by decreasing its affinity without affecting the number of binding sites. Normal activation of NMDA receptor is important for neuritic growth, synaptogenesis, long-term potentiation and synaptic plasticity. Therefore, we speculate that any clinical condition causing lipid peroxidation of brain cell membranes could jeopardize these maturational processes in the developing brain causing neurological impairment.

Animals↗

PubMed1975

The mechanism of liver microsomal lipid peroxidation.

In the presence of Fe-3+ and complexing anions, the peroxidation of unsaturated liver microsomal lipid in both intact microsomes and in a model system containing extracted microsomal lipid can be promoted by either NADPH and NADPH : cytochrome c reductase or by xanthine and xanthine oxidase. Erythrocuprein effectively inhibits the activity promoted by xanthine and xanthine oxidase but produces much less inhibition of NADPH-dependent peroxidation. The singlet-oxygen trapping agent, 1, 3-diphenylisobenzofuran, had no effect on NADPH-dependent peroxidation but strongly inhibited the peroxidation promoted by xanthine and xanthine oxidase. NADPH-dependent lipid peroxidation was also shown to be unaffected by hydroxyl radical scavengers.. The addition of catalase had no effect on NADPH-dependent lipid peroxidation, but it significantly increased the rate of malondialdehyde formation in the reaction promoted by xanthine and xanthine oxidase. The results demonstrate that NADPH-dependent lipid peroxidation is promoted by a reaction mechanism which does not involve either superoxide, singlet oxygen, HOOH, or the hydroxyl radical. It is concluded that NADPH-dependent lipid peroxidation is initiated by the reduction of Fe-3+ followed by the decomposition of hydroperoxides to generate alkoxyl radicals. The initiation reaction may involve some form of the perferryl ion or other metal ion species generated during oxidation of Fe-2+ by oxygen.

Animals↗

PubMed1991

The chemical basis for the ferriprotoporphyrin IX-chloroquine complex induced lipid peroxidation.

Ferriprotoporphyrin IX (FPIX) forms a coordination complex with chloroquine, an anti-malarial drug. The FPIX-chloroquine complex strongly promotes the peroxidative cleavage of phospholipid membrane. Iron in the complex is essential for the complex to induce lipid peroxidation. In this paper a more detailed mechanism of the complex promoted lipid peroxidation was investigated. Apotransferrin exhibited no apparent inhibition of the complex evoked lipid peroxidation, indicating no mobilization of iron from the complex. No significant inhibitory effect by superoxide dismutase, catalase and sodium benzoate on the complex induced lipid peroxidative reaction, suggesting little involvement of superoxide anion, hydrogen peroxide and hydroxyl radical in the reaction. Quinine and mefroquine, blood shizontocidal drugs as well as chloroquine, formed a complex with FPIX and each complex more rapidly induced lipid peroxidation than FPIX alone. Primaquine, which is not as effective as quinine or mefroquine on an intraerythrocytic malaria parasite, neither coordinated to FPIX nor promoted lipid peroxidation. The complex formation between FPIX and chloroquine, quinine or mefroquine could play a key role in their anti-malarial actions.

Animals↗

PubMed1982

Levels of lipid peroxidation in hepatocytes isolated from aging rats fed an antioxidant-free diet.

Enzymatically isolated hepatocytes were utilized to evaluate levels of lipid peroxidation in young (3 months), adult (12 months) and aged (25 months) Fisher-344 female rats. Lipid peroxidation was measured by assaying levels of malonaldehyde, a by-product of the peroxidation reaction. Young, adult and aged animals were fed a liquid antioxidant-free diet for 21 days prior to the hepatocyte isolation. Cells isolated from young rats demonstrated the highest levels of lipid peroxidation (microgram of malonaldehyde/10(6) cells). This increase may be a result of the isolation procedure or of metabolic differences found in younger animals. When hepatocytes from aged animals on the antioxidant-free diet were incubated in the presence of lipid peroxidation inducers, such as cumene hydroperoxide or NADPH, significant elevations in lipid peroxidation over comparable adult values were observed. Aged hepatocytes appear to be more susceptible to the peroxidation process than adult hepatocytes, possibly due to defective peroxidation defenses.

Aging↗