Xenobiotic Metabolism
Mostrando 13-24 de 68 artigos, teses e dissertações.
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13. Molecular cloning of a family of xenobiotic-inducible drosophilid cytochrome P450s: Evidence for involvement in host-plant allelochemical resistance
Cytochrome P450s constitute a superfamily of genes encoding mostly microsomal hemoproteins that play a dominant role in the metabolism of a wide variety of both endogenous and foreign compounds. In insects, xenobiotic metabolism (i.e., metabolism of insecticides and toxic natural plant compounds) is known to involve members of the CYP6 family of cytochrome P
The National Academy of Sciences of the USA.
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14. An essential role for nuclear receptors SXR/PXR in detoxification of cholestatic bile acids
Hepatic hydroxylation is an essential step in the metabolism and excretion of bile acids and is necessary to avoid pathologic conditions such as cholestasis and liver damage. In this report, we demonstrate that the human xenobiotic receptor SXR (steroid and xenobiotic receptor) and its rodent homolog PXR (pregnane X receptor) serve as functional bile ac
The National Academy of Sciences.
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15. Activation of PXR induces hypercholesterolemia in wild-type and accelerates atherosclerosis in apoE deficient mice[S]
The nuclear hormone receptor pregnane X receptor (PXR; also called SXR) functions as a xenobiotic sensor to coordinately regulate xenobiotic metabolism via transcriptional regulation of xenobiotic-detoxifying enzymes and transporters. Although many clinically relevant PXR ligands have been shown to affect cholesterol levels, the role of PXR in cholesterol ho
The American Society for Biochemistry and Molecular Biology.
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16. Metabolism of ethanol and carcinogens by glutathione transferases.
Nonoxidative alcohol metabolism to form fatty acid ethyl esters contributes to alcohol-related end-organ damage, and these products are formed by two synthase enzymes. We recently purified the major (pI 4.9) synthase from human myocardium. The N-terminal sequence (A P Y T V V Y F P V R G R X K A L R M L X A D) is greater than 73% identical with that of a neu
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17. Regulation of a xenobiotic sulfonation cascade by nuclear pregnane X receptor (PXR)
The nuclear receptor PXR (pregnane X receptor) protects the body from hepatotoxicity of secondary bile acids such as lithocholic acid (LCA) by inducing expression of the hydroxylating cytochrome P450 enzyme CYP3A and promoting detoxification. We found that activation of PXR also increases the activity and gene expression of the phase II conjugating enzyme de
The National Academy of Sciences.
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18. SAGE Analysis of Transcriptome Responses in Arabidopsis Roots Exposed to 2,4,6-Trinitrotoluene1
Serial analysis of gene expression was used to profile transcript levels in Arabidopsis roots and assess their responses to 2,4,6-trinitrotoluene (TNT) exposure. SAGE libraries representing control and TNT-exposed seedling root transcripts were constructed, and each was sequenced to a depth of roughly 32,000 tags. More than 19,000 unique tags were identified
The American Society for Plant Biologists.
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19. Nuclear receptors constitutive androstane receptor and pregnane X receptor ameliorate cholestatic liver injury
Cholestasis is associated with accumulation of bile acids and lipids, and liver injury. The constitutive androstane receptor (CAR) and pregnane X receptor (PXR) are xenobiotic nuclear receptors that coordinate protective hepatic responses to potentially toxic stimuli, including bile acids. We investigated the role of these receptors in the regulation of bile
National Academy of Sciences.
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20. Availability of specific reductases controls the temporal activity of the cytochrome P450 complement of Streptomyces coelicolor A3(2)
The annotated genome of Streptomyces coelicolor A3(2) revealed 18 cytosolic cytochromes P450 (CYPs) with six ferredoxin (fdx) proteins and two soluble ferredoxin reductases (fpr), their putative electron transport proteins. mRNA expression was observed for all 18 CYPs throughout growth and secondary metabolism, from 3 h after spore germination, and all CYP p
National Academy of Sciences.
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21. Genetic Variations in Xenobiotic Metabolic Pathway Genes, Personal Hair Dye Use, and Risk of Non-Hodgkin Lymphoma
From 1996 to 2000, the authors conducted a population-based case-control study among Connecticut women to test the hypothesis that genetic variation in xenobiotic metabolic pathway genes modifies the relation between hair dye use and risk of non-Hodgkin lymphoma. No effect modifications were found for women who started using hair dyes in 1980 or afterward. F
Oxford University Press.
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22. Reciprocal activation of Xenobiotic response genes by nuclear receptors SXR/PXR and CAR
The cytochrome P450 (CYP) gene products such as CYP3A and CYP2B are essential for the metabolism of steroid hormones and xenochemicals including prescription drugs. Nuclear receptor SXR/PXR (steroid and xenobiotic receptor/pregnenolone X receptor) has been shown both biochemically and genetically to activate CYP3A genes, while similar studies have establishe
Cold Spring Harbor Laboratory Press.
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23. Metabolism of aflatoxin B1 by rat hepatic microsomes induced by polyhalogenated biphenyl congeners.
The metabolism of aflatoxin B1 to aflatoxins M1 and Q1 by rat liver microsomes from animals pretreated with polychlorinated or polybrominated biphenyl congeners depended on the structure of the halogenated biphenyl inducers. Microsomes from rats treated with phenobarbital (PB) or halogenated biphenyls that exhibit PB-type activity preferentially enhanced the
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24. Metabolic pathways utilized by Phanerochaete chrysosporium for degradation of the cyclodiene pesticide endosulfan.
Recent studies have shown that cultures of white rot fungi not favoring the production of lignin and manganese peroxidases are effective in degrading certain xenobiotics. In this study we have used endosulfan as a model xenobiotic to assess the enzymatic mechanisms of pesticide metabolism under ligninolytic (nutrient-deficient) and nonligninolytic (nutrient-