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Rebelo D, Correia AT, Nunes B. Acute and chronic effects of environmental realistic concentrations of clofibric acid in Danio rerio: Behaviour, oxidative stress, biotransformation and lipid peroxidation endpoints. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2020; 80:103468. [PMID: 32805388 DOI: 10.1016/j.etap.2020.103468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 07/24/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
Due to their widespread use, pharmaceuticals can be metabolized, excreted and ultimately discarded in the environment, thereby affecting aquatic organisms. Lipid-regulating drugs are among the most prescribed medications around the world, controlling human cholesterol levels, in more than 20 million patients. Despite this growing use of lipid-regulating drugs, particularly those whose active metabolite is clofibric acid, the potential toxicological effects of these pharmaceuticals in the environment is not fully characterized. This work intended to characterize the toxicity of an acute (120 hours post-fertilization) and chronic (60 days post-fertilization) exposures to clofibric acid in concentrations of 10.35, 20.7, 41.4, 82.8, and 165.6 μg L-1 in zebrafish (Danio rerio). The concentrations which were implemented in both exposures were based on predicted environmental concentrations for Portuguese surface waters. The acute effects were analysed focusing on behavioural endpoints (small and large distance travelled, swimming time and total distance travelled), biomarkers of oxidative stress (activity of the enzymes superoxide dismutase, Cu/Zn- and Mn SOD; catalase, CAT; glutathione peroxidase, Se- and total GPx), biotransformation (activity of glutathione S-transferases, GSTs) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Chronically exposed individuals were also histologically analysed for sex determination and gonadal developmental stages. In terms of acute exposure, significant alterations were reported, in terms of behavioural alterations (hypoactivity), followed by an overall increase in all tested biomarkers. Chronically exposed organisms did not show alterations in terms of sex ratio and maturation stages, suggesting that clofibric acid did not act as an endocrine disruptor. Moreover, the metabolism of clofibric acid resulted in increased levels of both forms of SOD activity, especially for animals exposed to higher levels of this drug. An increase of CAT activity was observed in fish exposed to low levels, and a decrease in those exposed to higher amounts of clofibric acid. Both GPx forms had their activities increased. The enzyme of biotransformation GSTs were increased at low levels of clofibric acid but inhibited at higher amounts of this substance. Lipid peroxidation levels were also changed, with an induction of this parameter with increasing amounts of clofibric acid. Changes also occurred in behavioural endpoints and patterns for control organisms and for those exposed to clofibric acid were significantly distinct, for all types (light and darkness) of exposure, and for the two analysed endpoints (small and large distance). Results from this assay allow inferring that clofibric acid can have an ecologically relevant impact in living organisms exposed to this substance, with putative effects on the metabolism of individuals, affecting their behaviour and ultimately their survival.
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Affiliation(s)
- D Rebelo
- Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; Centro de Estudos do Ambiente e do Mar (CESAM), Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - A T Correia
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos SN, 4550-208 Matosinhos, Portugal; Faculdade de Ciências da Saúde, Universidade Fernando Pessoa (UFP), Rua Carlos da Maia 296, 4200-150, Porto, Portugal
| | - B Nunes
- Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; Centro de Estudos do Ambiente e do Mar (CESAM), Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
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Nunes-Souza V, Dias-Júnior NM, Eleutério-Silva MA, Ferreira-Neves VP, Moura FA, Alenina N, Bader M, Rabelo LA. 3-Amino-1,2,4-Triazole Induces Quick and Strong Fat Loss in Mice with High Fat-Induced Metabolic Syndrome. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:3025361. [PMID: 32351670 PMCID: PMC7174953 DOI: 10.1155/2020/3025361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 01/22/2020] [Accepted: 02/24/2020] [Indexed: 01/24/2023]
Abstract
BACKGROUND Obesity is a growing epidemic with limited effective treatments and an important risk factor for several diseases such as metabolic syndrome (MetS). In this study, we aimed to investigate the effect of 3-amino-1,2,4-triazole (ATZ), an inhibitor of catalase and heme synthesis, in a murine model for MetS. METHODS Male C57BL/6 mice with high-fat diet-induced MetS received ATZ (500 mg·kg-1·24 h-1) for 12 weeks. RESULTS The HFD group showed increased blood pressure and body weight, enhanced fat deposition accompanied by an increase in adipocyte diameter, and decreased lipolysis in white adipose tissue (WAT). The expression of genes related to inflammation was increased in WAT of the HFD group. Concurrently, these mice exhibited an increase in leptin, nonesterified fatty acid (NEFA), insulin, and glucose in plasma, coupled with glucose intolerance and insulin resistance. Strikingly, ATZ prevented the increase in blood pressure and the HFD-induced obesity as observed by lower body weight, WAT index, triglycerides, NEFA, and leptin in plasma. ATZ treatment also prevented the HFD-induced increase in adipocyte diameter and even induced marked atrophy and the accumulation of macrophages in this tissue. ATZ treatment also improved glucose metabolism by increasing glucose tolerance and insulin sensitivity, GLUT4 mRNA expression in WAT in parallel to decreased insulin levels. CONCLUSIONS In the context of HFD-induced obesity and metabolic syndrome, the fat loss induced by ATZ is probably due to heme synthesis inhibition, which blocks adipogenesis by probably decreased RevErbα activity, leading to apoptosis of adipocytes and the recruitment of macrophages. As a consequence of fat loss, ATZ elicits a beneficial systemic antiobesity effect and improves the metabolic status.
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Affiliation(s)
- Valéria Nunes-Souza
- Laboratório de Reatividade Cardiovascular, Setor de Fisiologia, Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Núcleo de Síndrome Metabólica, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
- Departamento de Fisiologia e Farmacologia, Centro de Biociências (CB), Universidade Federal de Pernambuco (UFPE), Recife, Pernambuco, Brazil
| | - Nelson Miguel Dias-Júnior
- Laboratório de Reatividade Cardiovascular, Setor de Fisiologia, Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Núcleo de Síndrome Metabólica, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Marcos Antônio Eleutério-Silva
- Laboratório de Reatividade Cardiovascular, Setor de Fisiologia, Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Núcleo de Síndrome Metabólica, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Faculdade de Medicina, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Vanessa P Ferreira-Neves
- Laboratório de Reatividade Cardiovascular, Setor de Fisiologia, Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Núcleo de Síndrome Metabólica, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Fabiana Andréa Moura
- Faculdade de Nutrição (FANUT), Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany
| | - Michael Bader
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
- Charité University Medicine, Berlin, Germany
- Institute for Biology, University of Lübeck, Germany
| | - Luíza A Rabelo
- Laboratório de Reatividade Cardiovascular, Setor de Fisiologia, Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Núcleo de Síndrome Metabólica, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
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Lee JN, Park J, Kim SG, Kim MS, Lim JY, Choe SK. 3-Aminotriazole protects against cobalt (II) chloride-induced cytotoxicity by inhibiting reactive oxygen species formation and preventing mitochondrial damage in HepG2 cells. Mol Cell Toxicol 2017. [DOI: 10.1007/s13273-017-0013-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lee JN, Kim SG, Lim JY, Dutta RK, Kim SJ, Choe SK, So HS, Park R. 3-Aminotriazole protects from CoCl2-induced ototoxicity by inhibiting the generation of reactive oxygen species and proinflammatory cytokines in mice. Arch Toxicol 2015; 90:781-91. [DOI: 10.1007/s00204-015-1506-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/16/2015] [Indexed: 12/20/2022]
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Nunes B, Carvalho F, Guilhermino L. Acute and chronic effects of clofibrate and clofibric acid on the enzymes acetylcholinesterase, lactate dehydrogenase and catalase of the mosquitofish, Gambusia holbrooki. CHEMOSPHERE 2004; 57:1581-1589. [PMID: 15519403 DOI: 10.1016/j.chemosphere.2004.09.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 09/08/2004] [Accepted: 09/10/2004] [Indexed: 05/24/2023]
Abstract
The objective of this study was to investigate both acute and chronic effects of clofibrate and clofibric acid on the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH) and catalase (CAT) of the mosquitofish (Gambusia holbrooki). AChE, commonly used as a biomarker of neurotoxicity, was determined in the total head. LDH, an important enzyme of anaerobic metabolism, was quantified in dorsal muscle, and CAT, enzyme which has been used as indicative parameter of peroxisome proliferation, was determined in the liver. Furthermore, alterations of body and liver weight were also determined, through the calculation of the ratios final body weight/initial body weight, liver weight/final body weight, liver weight/gills weight and liver weight/head weight. Acute exposure of G. holbrooki to both clofibrate and clofibric acid induced a decrease in liver CAT activity, an increase in muscle LDH activity, while no effects were observed on AChE activity. However, chronic exposure did not alter significantly the enzymatic activities, suggesting reduced or null effects over these pathways, relative to effects reported in other species. No effects were observed for the calculated ratios, except a significant weight reduction for males chronically exposed to clofibrate.
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Affiliation(s)
- B Nunes
- ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Departamento de Estudos de Populações, Laboratório de Ecotoxicologia, Universidade do Porto, Largo Prof. Abel Salazar, 2, 4099-003 Porto, Portugal.
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Cadenas S, Rojas C, Pérez-Campo R, López-Torres M, Barja G. Effect of dietary vitamin C and catalase inhibition of antioxidants and molecular markers of oxidative damage in guinea pigs. Free Radic Res 1994; 21:109-18. [PMID: 7921163 DOI: 10.3109/10715769409056562] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Guinea pigs were fed for five weeks with two diets with different levels of vitamin C, low (33 mg of Vit C/Kg diet) and high (13,200 mg of Vit C/Kg of diet). Catalase was inhibited with 3-amino-1,2,4-triazole (AT) in half of the animals from each dietary group. AT caused an almost complete depletion of liver catalase activity (90%) in both dietary groups. Vitamin C supplementation increased total glutathione peroxidase activity and tissue vitamin C level and decreased levels of protein carbonyls and malondialdehyde (MDA) in both treated and non-treated animals. This vitamin C supplementation did not change any of the other antioxidant defences studied. Our results show that dietary vitamin C supplementation increases global antioxidant capacity and decreases endogenous oxidative damage in the guinea pig liver under normal non-stressful conditions. This supports the protective value of dietary antioxidant supplementation.
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Affiliation(s)
- S Cadenas
- Department of Animal Biology II (Animal Physiology), Faculty of Biology, Complutense University, Madrid, Spain
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López-Torres M, Pérez-Campo R, Barja de Quiroga G. Aminotriazole effects on lung and heart H2O2 detoxifying enzymes and TBA-RS at two pO2. PHARMACOLOGY & TOXICOLOGY 1990; 66:27-31. [PMID: 2308904 DOI: 10.1111/j.1600-0773.1990.tb00696.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In order to clarify the physiological role in vivo of H2O2-detoxifying enzymes at low and high levels of O2 tension we studied catalase (CAT), glutathione peroxidases (GP), and in vivo peroxidation (TBA-RS) in the lung and heart of Rana perezi frogs chronically treated with hyperoxia, aminotriazole (AT) -a CAT inhibitor-, or both. Hyperoxia did not change CAT, GP or TBA-RS. Aminotriazole caused an almost complete depletion of CAT, a 30% decrease of GP and a 132% (lung) to 200% (heart) increase of TBA-RS. Changes similar to these were found in the group treated with AT in hyperoxia. No mortality or changes in total or organ weight occurred in the experimental groups. Main conclusions are: (1) The maximal hyperoxia tolerance showed by frogs among vertebrates does not need antioxidant enzyme induction from lung or heart and is probably related to the presence of high constitutive levels of GP in relation to metabolic rate. (2) Even in normoxia the tissues present significant amounts of H2O2, and CAT is needed to avoid oxidative damage. GP does not compensate its absence. The implications of these results in relation to oxygen toxicity in man is discussed.
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Affiliation(s)
- M López-Torres
- Department of Animal Physiology (Animal Biology II), Faculty of Biology, Complutense University, Madrid, Spain
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Barja de Quiroga G, López-Torres M, Pérez-Campo R. Catalase is needed to avoid tissue peroxidation in Rana perezi in normoxia. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1989; 94:391-8. [PMID: 2576777 DOI: 10.1016/0742-8413(89)90087-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. In order to clarify the relative role of catalase (CAT) and glutathione peroxidases (GSH-Px) at normal and high O2 tensions, Rana perezi frogs were chronically treated with aminotriazole (AT), hyperoxia, or both. 2. A 100% survival was observed with both treatments. Hyperoxia increased liver catalase and kidney TBA-RS and decreased GSH-Px. 3. AT caused quantitatively higher alterations than hyperoxia in both organs: CAT was depleted, TBA-RS increased (114% in kidney) and GSH-Px decreased. 4. It is concluded that in Rana perezi (a) CAT, in spite of its much higher KM and Vmax in relation to GSH-Px, is needed to avoid oxidative stress even in normoxia; (b) normoxic tissues have significative amounts of H2O2; (c) GSH-Px does not compensate the lack of CAT.
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Affiliation(s)
- G Barja de Quiroga
- Department of Animal Biology-II (Animal Physiology), Faculty of Biology, Complutense University, Madrid, Spain
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MacDonald RS, Swan PB. The effect of three hypolipidemic drugs on catalase activity and peroxisomal and mitochondrial palmitate oxidation in rat cardiac and skeletal muscle. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 880:153-60. [PMID: 3942787 DOI: 10.1016/0304-4165(86)90075-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Catalase activity and peroxisomal and mitochondrial palmitate oxidation have been investigated in cardiac and skeletal muscle from rats fed clofibrate, ciprofibrate or nafenopin in an unrefined diet for different periods of time. Nafenopin was also added to either a high carbohydrate (70% of kilocalories from glucose) or high fat (70% of kilocalories from lard) diet and fed to rats for either 1 or 3 weeks. Catalase activity was elevated in all muscles from rats fed the hypolipidemic drugs. The response of catalase activity in muscle to clofibrate was dose-dependent. The response time of catalase activity was different in individual muscles. Peroxisomal palmitate oxidation was elevated in the heart and soleus muscle from rats fed nafenopin in either the high-carbohydrate or the high-fat diet. There was no change in peroxisomal palmitate oxidation in psoas or extensor digitorum longus muscle from rats fed the drugs. Mitochondrial palmitate oxidation was only slightly increased by nafenopin in the heart and soleus muscles after 3 weeks of nafenopin feeding. The results suggest that the cardiac muscle, like the liver, responds to hypolipidemic drug treatment with an increase in peroxisomal fat oxidation. The skeletal muscle response is less specific and that tissue may not contribute to the hypolipidemic effect of the drugs. The findings also suggest that these drugs do not induce peroxisome proliferation in skeletal muscle.
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Moore KH, Solomon FJ. Cardiac and hepatic acyl-CoA and acylcarnitine hydrolase activities in clofibrate-fed rabbits. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1985; 80:355-9. [PMID: 2861021 DOI: 10.1016/0742-8413(85)90068-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Catalase activity in the heart of male rabbits was 21% of that found in the liver; clofibrate feeding (0.3% w/w for 10 days) resulted in an 80% increase in both cardiac and hepatic catalase activities. Fatty acyl-CoA oxidase activity in control heart was 11% of that found in control liver; this peroxisomal activity did not increase subsequent to clofibrate feeding. Only acyl-CoA hydrolase activity in the cardiac supernatant was elevated by clofibrate feeding. Acylcarnitine hydrolase activity was increased significantly in the homogenate, extract and supernatant of both heart and liver from the clofibrate-fed rabbit. Clofibrate feeding increased CoASH and carnitine tissue levels in heart and liver.
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Moody DE, Reddy JK, Azarnoff DL. Peroxisome-associated enzymes and serum lipids in tumour-bearing rats treated with peroxisome-proliferating agents. Biochem Pharmacol 1984; 33:2591-7. [PMID: 6431985 DOI: 10.1016/0006-2952(84)90630-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Xenobiotic induction of liver peroxisomes is associated with hypolipidemia. To test the involvement of the peroxisome proliferation with the hypolipidemia, male rats were inoculated in the groin with five different tumors: an aflatoxin-induced hepatoma, a lasiocarpine-induced hepatoma, an actinomycin-D-induced mesothelioma, a lasiocarpine-induced squamous cell carcinoma, and a methylnitrosourea-induced fibrosarcoma. After the tumours reached a suitable size, the rats were fed diets containing the peroxisome-proliferating hypolipidemic agents tibric acid (2-chloro-5-[3,5-dimethylpiperidinosulfonyl] benzoic acid) or Wy-14,643 ([4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio] acetic acid) for 2 weeks. Liver and tumor tissues were then assayed for the peroxisome-associated enzymes, catalase and carnitine acetyltransferase, and correlated with serum levels of triglyceride and cholesterol. The presence of the tumors caused a predictable decrease in liver catalase and a slight elevation of liver carnitine acetyltransferase. Serum cholesterol was elevated slightly, while serum triglyceride levels were elevated, unchanged, or decreased in the tumor-bearing rats maintained on control diet. Inclusion of the xenobiotics in the diet caused increases in liver weight, catalase, and carnitine acetyltransferase. Serum triglycerides were decreased in the three groups which were not already decreased, but a decrease in serum cholesterol was only found in one group after only one of the treatments. The latter finding demonstrates that peroxisomal enzyme induction can be dissociated from the decrease in serum cholesterol. The data were further evaluated by testing for correlations between the changes in these components, comparing changes within groups and between groups. These correlations indicate an inverse biological association between liver catalase and serum cholesterol and between liver carnitine acetyltransferase and serum triglyceride. The latter correlation was inverse only for comparisons between groups, suggesting that carnitine acetyltransferase activity is associated with serum triglycerides only during the perturbational state.
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Kornbrust DJ, Barfknecht TR, Ingram P, Shelburne JD. Effect of di(2-ethylhexyl) phthalate on DNA repair and lipid peroxidation in rat hepatocytes and on metabolic cooperation in Chinese hamster V-79 cells. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1984; 13:99-116. [PMID: 6716514 DOI: 10.1080/15287398409530484] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Experiments were conducted to test the hypothesis that the hepatocarcinogenicity of di(2-ethylhexyl) phthalate (DEHP) is due to its ability to produce DNA damage, either directly or as a result of the proliferation of peroxisomes and accompanying increased production of H2O2 and other DNA--damaging oxygen radicals induced by sustained exposure to the plasticizer. DNA repair, as assessed by the autoradiographic measurement of unscheduled DNA synthesis (UDS), was not observed in primary rat hepatocytes exposed in vitro to 10(-5)-10(-2) M DEHP or in vivo by a single gavage dose of 5 g DEHP/kg body weight administered 2, 15, or 24 h prior to the isolation of hepatocytes. Thus, DEHP does not appear to directly produce repairable DNA damage in rat hepatocytes. Sustained feeding of DEHP at a dietary concentration of 2% led to a marked proliferation of peroxisomes in the liver after 4 wk. Additional administration of a single gavage dose of 5 g DEHP/kg body weight to animals fed the 2% diet for 4 or 8 wk, as well as to 4-wk-fed animals that were also pretreated with 3-amino-1,2,4-triazole to inhibit endogenous catalase activity, did not induce any detectable DNA repair in hepatocytes isolated 15 h following the single gavage dose of DEHP. Lipid peroxidation measured in the 9000 X g supernatant of livers from animals treated with a single dose of 5 g DEHP/kg body weight or the 2% DEHP diet for 6 wk plus a single dose of 5 g/kg body weight did not differ from controls. These findings suggest that DEHP does not elicit DNA damage or lipid peroxidation in liver consequent to the proliferation of peroxisomes resulting from prolonged administration. In addition, at noncytotoxic concentrations DEHP failed to produce a positive response in the Chinese hamster V-79 metabolic cooperation assay for tumor promoters.
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