Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

6-Chloro n-butyl phthalide (CBP) was orally administered to healthy, male Wistar rats pretreated with or without 3-methylcholanthrene (3-MC) by a single dose of 150 mg/kg, and urine samples were collected for 0-24 h. The urine sample was hydrolyzed with beta-glucuronidase, extracted and concentrated for TMS derivatization, and analysed on a GC-MS system for identification of CBP metabolities. Mass spectral analysis suggests that 7 CBP metabolites were present in the urine sample, and similar metabolism patterns were viewed in rats with or without pretreatment with 3-MC. Four main metabolites of CBP in rat urine were identified as alpha-beta oxolate, beta-gamma oxolate, beta-hydroxylate and gamma-hydroxylate, based on their chromatographic and mass spectral properties. Two hydroxylates have been previously identified in CBP metabolism by rat liver microsomes. The other two metabolites with higher polarity were tentatively identified as dihydroxylation products on the n-butyl side chain by the mass spectra of their TMS derivatives. One minor metabolite was found by the isotopic effect of chlorine, but its specific structure was undetermined. The difference between in vivo and in vitro metabolic profiles of CBP is also discussed.
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PMID:Metabolism of 6-chloro n-butyl phthalide in rat. 907 99

Tilmicosin is a semi-synthetic macrolide antibiotic, currently approved for veterinary use in cattle and swine respiratory disease. As the concentrations of tilmicosin are generally low in swine lung tissue, the interaction of tilmicosin with three types of swine phagocytes (monocyte-macrophages, alveolar macrophages, and neutrophils) was evaluated to provide an understanding of clinical efficacy. After incubation with radiolabelled tilmicosin, uptake was determined and expressed as the ratio of the intracellular (Ci) to the extracellular (Ce) drug concentration (Ci/Ce). Tilmicosin was avidly accumulated by the swine phagocytes (Ci/Ce 48-69 at 4 h incubation) with 51 to 85% localized in the lysosomes. Uptake was dependent on cell viability, temperature and pH, but was not influenced by the metabolic inhibitors, sodium cyanide or potassium fluoride. However, lipopolysaccharide (LPS) exposure increased tilmicosin uptake by the swine phagocytes. In neutrophils, upon removal of extracellular tilmicosin, 60% of the intracellular tilmicosin was effluxed within the first 30 min, but after 4 h of incubation in drug-free medium, 25% remained cell-associated. In contrast, after 4 h of incubation in drug-free medium, 60% and 45% of tilmicosin remained cell-associated, within alveolar macrophages and monocyte-derived macrophages, respectively. Tilmicosin uptake was observed to increase lysosomal enzyme (acid phosphatase, lysozyme and beta-glucuronidase) production. Finally, neutrophils were shown to transport and efflux bioactive tilmicosin in a test system measuring both neutrophil chemotaxis under agarose and a bioassay measuring inhibition of bacterial growth in the presence of antibiotic in agar. These in vitro interactions of tilmicosin with swine phagocytes suggest an integral role in effecting clinical efficacy.
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PMID:Intracellular accumulation, subcellular distribution and efflux of tilmicosin in swine phagocytes. 973 47

1. [R-2,6-3H]-4-n-nonylphenol was synthesized and a single dose (5 mg, 1850 KBq) orally administered to rainbow trout. After 48 h, the radioactivity present in the bile amounted 5.5%. More than ten biliary metabolites were separated by hplc and collected for subsequent mass spectrometry analysis. The metabolic profile was totally modified by beta-glucuronidase hydrolysis, showing that most of the metabolites were glucuronic acid conjugates. 2. Conjugated metabolites were identified by lc-ms analysis and their aglycones were analysed by gc-ms analysis as TMS and acetyl derivatives. 3. The major metabolite accounted for 52+/-11% of the biliary radioactivity and was identified as nonylphenol-glucuronide. 4. Nonylphenol was hydroxylated at both omega and omega-1 positions of the alkyl chain, giving 9-hydroxynonylphenol and 8-hydroxynonylphenol. 5. 9-Hydroxynonylphenol was oxidized to the corresponding acid, and subsequently beta-oxidized, yielding 7-(4-hydroxyphenyl)heptanoic acid, 5-(4-hydroxyphenyl)pentanoic acid, 3-(4-hydroxyphenyl)propionic acid and 3-(4-hydroxyphenyl)-2-propenoic acid.
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PMID:Characterization of biliary metabolites of 4-n-nonylphenol in rainbow trout (Oncorhynchus mykiss). 974 53

Tilmicosin is a semi-synthetic macrolide antibiotic, currently approved for veterinary use in cattle and swine respiratory disease, and is in development for use in poultry mycoplasma air sacculitis. In order to provide an understanding of clinical efficacy, the in vitro interaction of tilmicosin with three types of chicken phagocytes (MQ-NCSU macrophages, monocyte-macrophages, and heterophils) was evaluated. After incubation with radiolabeled tilmicosin, uptake was determined and expressed as the ratio of the cellular (Cc) to the extracellular (Ce) drug concentration (Cc:Ce). Tilmicosin was avidly accumulated by heterophils (Cc: Ce 138 at 4 h incubation vs 32 and 66, respectively, in MQ-NCSU and monocyte-macrophages) with 61 to 88% localized in the lysosomes. Uptake was dependent on cell viability, temperature, and pH, but was not influenced by metabolic inhibitors. However, phagocytosis of Pasteurella multocida and lipopolysaccharide exposure increased tilmicosin uptake by the chicken phagocytes. Upon removal of extracellular tilmicosin, 50% of the intracellular tilmicosin was effluxed within the first 30 min, but after 4 h of incubation in antibiotic-free medium, 30% remained cell-associated. Opsonized P. multocida significantly enhanced the release of tilmicosin from all three types of chicken phagocytes. Tilmicosin uptake was observed to increase lysosomal enzyme (acid phosphatase, lysozyme, avidin, and beta-glucuronidase) production. Finally, neutrophils were shown to transport and efflux bioactive tilmicosin in a test system measuring both neutrophil chemotaxis under agarose and a bioassay measuring inhibition of bacterial growth in the presence of antibiotic in agar. These in vitro observations of cellular pharmacology suggest a complex interaction between phagocytes and tilmicosin that contribute to clinical efficacy.
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PMID:Intracellular accumulation, subcellular distribution, and efflux of tilmicosin in chicken phagocytes. 977 59

A GC-MS method for the investigation on the metabolism of 6-methoxy n-butyl phthalide (MBP) is described. After oral administration of MBP, the rat urine sample was collected, hydrolyzed with beta-glucuronidase, extracted and concentrated for TMS derivatization, and then analyzed by GC-MS. MBP and its six oxidative metabolites were determined in the 0-24 h rat urine sample. The mass spectra of the metabolites and their derivatives were presented and the in vivo metabolic pathway was discussed.
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PMID:[Investigation on in vivo metabolism of 6-methoxy n-butyl phthalide]. 986 26

A GC-MS method for the investigation on the metabolism of n-butyl phthalide (NBP) is described. After oral administration of NBP to rats, urine was collected, hydrolyzed with beta-glucuronidase, extracted and concentrated for TMS derivatization, and then analyzed by GC-MS. HBP and its four oxidative metabolites were determined in 0-24 h, 24-48 h rat urine. The mass spectra of the metabolites and their derivatives were presented and the in vivo metabolic pathway was discussed.
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PMID:[Investigation on in vivo metabolism of n-butyl phthalide]. 986 47

A method based on gas chromatography-mass spectrometry-selected-ion monitoring was developed to measure the main metabolites of 17alpha-methyltestosterone, 17alpha-methyl-5alpha-androstan-3alpha,17beta-di ol and 17alpha-methyl-5beta-androstan-3alpha,17beta-dio l, in human urine. 17alpha-Methyl-[(2)H3]-5alpha-androstan-3alpha,1 7beta-diol and 17alpha-methyl-[(2)H3]-5beta-androstan-3alpha,17 beta-diol were used as internal standards. The methods involved purification using a Sep-Pak C(18) cartridge, hydrolysis by beta-glucuronidase from Ampullaria and derivatization with N-methyl-N-trimethylsilyl-trifluoroacetamide/dithioerythriol/ammon ium iodide. Quantitation was achieved by selected-ion monitoring of the characteristic fragment ions ([(M+H)-2xTMSOH]+) of the di-TMS derivatives on the chemical ionization mode. The method provides a specific, sensitive and reliable technique to determine the urine levels of 17alpha-methyl-5alpha-androstan-3alpha,17beta-di ol and 17alpha-methyl-5beta-androstan-3alpha,17beta-dio l, and can be applied to pharmacokinetic studies of 17alpha-methyltestosterone.
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PMID:Stable isotope dilution analysis of human urinary metabolites of 17alpha-methyltestosterone. 1087 96

Perphenazine enanthate has been used in wild animals as a tranquilizer during the period of adaptation to new environments to reduce stress, mortalities and injuries. A gas chromatographic procedure for the quantitative measurement of perphenazine in otter urine has been developed and validated. The method involved an enzymatic hydrolysis with beta-glucuronidase-arylsulfatase from Helix pomatia, followed by a solid-phase extraction with Bond Elut Certify cartridges. The resulting organic phase was evaporated, and the dry extract was derivatised with MSTFA to form the O-TMS derivative. The derivatised extracts were analysed by gas chromatography-mass spectrometry using SIM acquisition mode, measuring three diagnostic ions (m/z 246, 372 and 475). Another phenothiazine derivative, fluphenazine, was used as the internal standard (I.S.). Extraction recoveries for perphenazine and I.S. were 87.6 +/- 8.2% (n=4) and 106.7 +/- 13.4% (n=4), respectively. The calibration curves were linear in the range from 4 to 100 ng/ml (r2=0.99). The limits of detection and quantification were estimated as 1.2 and 3.5 ng/ml, respectively. Precision and accuracy obtained in intra-assay studies were in the ranges of 1.3-8.7 and 1.7-19.5%, respectively, using control samples containing 6, 16 and 60 ng/ml of perphenazine. In inter-assay experiments, precision ranged from 4.3 to 14.9% and accuracy from 3.1 to 11.8%. Examples of the application of the perphenazine quantification method in otter urines after administration of perphenazine enanthate are presented.
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PMID:Quantification of perphenazine in eurasian otter (Lutra lutra lutra) urine samples by gas chromatography-mass spectrometry. 1193 97

The in vivo phase I biotransformation of 17 alpha-methyltestosterone in the horse leads to the formation of a complex mixture of regio- and stereoisomeric C(20)O(2), C(20)O(3) and C(20)O(4) metabolites, excreted in urine as glucuronide and sulphate phase II conjugates. The major pathways of in vivo metabolism are the reduction of the A-ring (di- and tetrahydro), epimerisation at C-17 and oxidations mainly at C-6 and C-16. Some phase I metabolites have been identified previously by positive ion electron ionisation capillary gas chromatography/mass spectrometry (GC/EI + MS) mainly from the characteristic fragmentation patterns of their methyloxime-trimethylsilyl ether (MO-TMS), enol-TMS or TMS ether derivatives. Following oral administration of 17 alpha-methyltestosterone to two castrated thoroughbred male horses, the glucuronic acid conjugates excreted in post-administration urine samples were selectively hydrolysed by E. coli beta-glucuronidase enzymes. Unconjugated metabolites and the steroid aglycones obtained after enzymatic deconjugation were isolated from urine by solid-phase extraction, derivatised as MO-TMS ethers and analysed by GC/EI + MS. In addition to some of the known metabolites previously identified from the characteristic mass spectral fragmentation patterns of 17 alpha-methyl steroids, some isobaric compounds exhibiting a diagnostic loss of 103 mass units from the molecular ions with subsequent losses of trimethylsilanol or methoxy groups and an absence of the classical D-ring fragment ion were detected. From an interpretation of their mass spectra, these compounds were identified as 17-hydroxymethyl metabolites, formed in vivo in the horse by oxidation of the 17-methyl moiety of 17 alpha-methyltestosterone. This study reports on the GC/EI + MS identification of these novel 17-hydroxymethyl C(20)O(3) and C(20)O(4) metabolites of 17 alpha-methyltestosterone excreted in thoroughbred horse urine.
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PMID:In vivo biotransformation of 17 alpha-methyltestosterone in the horse revisited: identification of 17-hydroxymethyl metabolites in equine urine by capillary gas chromatography/mass spectrometry. 1256 42

A method to quantify metabolites of 17beta-nandrolone (17betaN) in boar and horse urine has been optimized and validated. Metabolites excreted in free form were extracted at pH 9.5 with tert-butylmethylether. The aqueous phases were applied to Sep Pak C18 cartridges and conjugated steroids were eluted with methanol. After evaporation to dryness, either enzymatic hydrolysis with beta-glucuronidase from Escherichia coli or solvolysis with a mixture of ethylacetate:methanol:concentrated sulphuric acid were applied to the extract. Deconjugated steroids were then extracted at alkaline pH with tert-butylmethylether. The dried organic extracts were derivatized with MSTFA:NH4I:2-mercaptoethanol to obtain the TMS derivatives, and were subjected to analysis by gas chromatography mass spectrometry (GC/MS). The procedure was validated in boar and horse urine for the following metabolites: norandrosterone, noretiocholanolone, norepiandrosterone, 5beta-estran-3alpha, 17beta-diol, 5alpha-estran-3beta, 17beta-diol, 5alpha-estran-3beta, 17alpha-diol, 17alpha-nandrolone, 17betaN, 5(10)-estrene-3alpha, 17alpha-diol, 17alpha-estradiol and 17beta-estradiol in the different metabolic fractions. Extraction recoveries were higher than 90% for all analytes in the free fraction, and better than 80% in the glucuronide and sulphate fractions, except for 17alpha-estradiol in the glucuronide fraction (74%), and 5alpha-estran-3beta, 17alpha-diol and 17betaN in the sulphate fraction (close to 70%). Limits of quantitation ranged from 0.05 to 2.1 ng mL(-1) in the free fraction, from 0.3 to 1.7 ng mL(-1) in the glucuronide fraction, and from 0.2 to 2.6 ng mL(-1) in the sulphate fraction. Intra- and inter-assay values for precision, measured as relative standard deviation, and accuracy, measured as relative standard error, were below 15% for most of the analytes and below 25%, for the rest of analytes. The method was applied to the analysis of urine samples collected after administration of 17betaN laureate to boars and horses, and its suitability for the quantitation of the metabolites in the three fractions has been demonstrated.
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PMID:Quantitation of 17beta-nandrolone metabolites in boar and horse urine by gas chromatography-mass spectrometry. 1738 11


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