Search results for "metabolite"
showing 10 items of 551 documents
Biomonitoring exposure assessment to contemporary pesticides in a school children population of Spain
2013
The exposure to pesticides amongst school-aged children (6-11 years old) was assessed in this study. One hundred twenty-five volunteer children were selected from two public schools located in an agricultural and in an urban area of Valencia Region, Spain. Twenty pesticide metabolites were analyzed in children's urine as biomarkers of exposure to organophosphate (OP) insecticides, synthetic pyrethroid insecticides, and herbicides. These data were combined with a survey to evaluate the main predictors of pesticide exposure in the children's population. A total of 15 metabolites were present in the urine samples with detection frequencies (DF) ranging from 5% to 86%. The most frequently detec…
Metabolism of apigenin by rat liver phase I and phase II enzymes and by isolated perfused rat liver
2004
The metabolism of apigenin, a low estrogenic flavonoid phytochemical, was investigated in rat using liver models both in vitro (subcellular fractions) and ex vivo (isolated perfused liver). In vitro, phase I metabolism led to the formation of three monohydroxylated derivatives: luteolin which was the major metabolite (K(m) = 22.5 +/- 1.5 microM; V(max) = 5.605 +/- 0.090 nmol/min/mg protein, means +/- S.E.M.), scutellarein, and iso-scutellarein. These oxidative pathways were mediated by cytochrome P450 monooxygenases (P450s). The use of P450 inhibitors and inducers showed that CYP1A1, CYP2B, and CYP2E1 are involved. In vitro studies of phase II metabolism indicated that apigenin underwent co…
Protein oxidation in chronic kidney disease.
2013
An imbalance between oxidative processes and antioxidant systems has been widely demonstrated in chronic kidney diseases (CKD). In this study we enrolled 26 healthy subjects, 27 patients with CKD on conservative treatment (CT-CKD) with various degrees of renal failure, and 31 CKD subjects in haemodialysis treatment (HD-CKD), evaluated before and after a standard haemodialysis session. In each group we measured protein carbonyl groups (PC) as an index of protein oxidation, lipid peroxidation (TBARS) and two plasma markers of leukocyte activation, elastase and myeloperoxidase (MPO). In CT-CKD subjects the PC level was significantly higher than in normal controls, and it was negatively correla…
Acetaldehyde self-administration by a two-bottle choice paradigm: Consequences on emotional reactivity, spatial learning, and memory
2015
Abstract Acetaldehyde, the first alcohol metabolite, is responsible for many pharmacological effects that are not clearly distinguishable from those exerted by its parent compound. It alters motor performance, induces reinforced learning and motivated behavior, and produces different reactions according to the route of administration and the relative accumulation in the brain or in the periphery. The effective activity of oral acetaldehyde represents an unresolved field of inquiry that deserves further investigation. Thus, this study explores the acquisition and maintenance of acetaldehyde drinking behavior in adult male rats, employing a two-bottle choice paradigm for water and acetaldehyd…
Metabolism of coumarin by precision-cut calf liver slices and calf liver microsomes.
1995
1. The metabolism of 50 microM [3-14C]coumarin has been studied in precision-cut-calf liver slices. 2. The metabolism of 50 microM coumarin to 7-hydroxycoumarin has also been examined in calf, rat, Cynomolgus monkey and human liver microsomal preparations. 3. In precision-cut calf liver slices, [3-14C]coumarin was metabolized to various polar products and to metabolite(s) that bound covalently to calf liver slice proteins. The polar products included 7-hydroxycoumarin (which was extensively conjugated with D-glucuronic acid and/or sulphate), metabolites of the 3-hydroxylation pathway (mainly o-hydroxyphenylethanol and o-hydroxyphenylacetic acid), and unknown metabolites. 4. Coumarin 7-hydro…
A Simple Microassay for the Determination of Hydrazine in Biological Samples. Effect of Hydrazine and Isoniazid on Liver and Brain Glutathione
1987
A simple microassay for the determination of hydrazine in laboratory samples is presented. The colored product of the reaction of p-dimethylaminobenzaldehyde with hydrazine was tested at 470 nm using double-beam mode in different samples. Internal standards and data on blood serum, liver, and brain of rats treated with hydrazine or isoniazid are presented. The tissue glutathione content of these rats was determined, and the possible implication of glutathione in the brain toxicity of hydrazine is discussed.
Spontaneous release of endogenous 5-hydroxytryptamine and 5-hydroxyindoleacetic acid from the isolated vascularly perfused ileum of the guinea-pig
1987
The spontaneous release of 5-hydroxytryptamine and its metabolite 5-hydroxyindoleacetic acid from the enterochromaffin cells of the small intestine into the portal circulation was investigated in vitro using the vascularly perfused ileum of the guinea-pig. The release of 5-hydroxytryptamine decreased by 70% in a calcium-free medium and by 35% in the presence of tetrodotoxin. Inhibition of monoamine oxidase activity by pargyline (100 microM) had no effect on the spontaneous release of 5-hydroxytryptamine although it caused a 75% reduction in the outflow of 5-hydroxyindoleacetic acid. Imipramine (1 microM), an inhibitor of neuronal uptake of 5-hydroxytryptamine, reduced the 5-hydroxyindoleace…
Multi-step metabolic activation of benzene. Effect of superoxide dismutase on covalent binding to microsomal macromolecules, and identification of gl…
1980
Abstract Incubation of [ 14 C]benzene or [ 14 C]phenol with liver microsomes from untreated rats, in the presence of a NADPH-generating system, gave rise to irreversible binding of metabolites to microsomal macromolecules. For both substrates this binding was inhibited by more than 50% by addition of superoxide dismutase to the incubation mixtures. The decrease in binding was compensated for by accumulation of [ 14 C]hydroquinone, indicating superoxide-mediated oxidation of hydroquinone as one step in the activation of benzene to metabolites binding to microsomal macromolecules. Since our previous work had shown that binding occurred mainly with protein rather than ribonucleic acid and was …
1H NMR-based metabolomics studies of urine reveal differences between type 1 diabetic patients with high and low HbAc1 values
2012
Abstract The aim of this study was to investigate relation between level of HbAc1 and concentration of metabolites in urine of T1D patients. To test this hypothesis the 1 H NMR (proton nuclear magnetic resonance) target analysis of crucial urine metabolites combined with chemometric approach were applied. Urine samples were collected from 30 children and teenagers aged 4–19 with T1D and 12 healthy children, aged 9, as control group. Patients were divided into two groups according to their level of glycated hemoglobin (HbA1c): below (L-T1D) and above 6.5% (H-T1D). The multivariate data analysis (OPLS-DA) was used to explore data and generate the models for selected groups of patients. Two ta…
Adipose Tissue Dysfunction and Altered Systemic Amino Acid Metabolism Are Associated with Non-Alcoholic Fatty Liver Disease
2015
Article