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)

A sensitive, specific GLC assay was developed for the determination of ethinamate in plasma and its major metabolite, trans-4-hydroxyethinamate, in urine. The assay uses a mass internal standard of dimethylethinamate. Ethinamate is extracted from alkalinized plasma with dichloromethane. Urine samples require beta-glucuronidase hydrolysis prior to extraction of hydroxyethinamate. The dichloromethane is removed by evaporation, and the compounds are measured by GLC using a flame-ionization detector. By using GLC-chemical-ionization mass spectrometry, the compounds measured were identified as the intact ethinamates. Plasma and urine data are presented from a bioavailability study to demonstrate the utility of this method. From these data, the ethinamate plasma half-life was calculated as 1.9 +/- 0.3 hr.
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PMID:GLC determination of ethinamate and its hydroxy derivative in biological fluids. 56 Apr 72

A simple rapid method for simultaneous ethosuximide and phenobarbital assay in brain tissue, serum and urine has been developed. Extraction of samples from brain tissue and serum were performed with dichloromethane at low pH in the presence of an excess of ammonium sulfate. Glucuronide conjugates in urine samples were hydrolyzed by enzymatic cleavage with beta-glucuronidase and then extracted with dichloromethane. The extracts were analyzed using a Spherisorb 5 ODS column and a mixture of acetonitrile, methanol and phosphate buffer (21:24:55, v/v) as eluent. No interference was encountered and the method is both precise and reproducible.
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PMID:Simultaneous measurement of ethosuximide and phenobarbital in brain tissue, serum and urine by HPLC. 273 17

The liquid chromatographic (LC) method described, suitable for use with both blood plasma and urine, is applicable for determination of zearalenone and alpha-zearalenol at levels as low as 0.5 ng/mL plasma and 5 ng/mL urine. The sample is incubated overnight with beta-glucuronidase to analyze for both conjugated and unconjugated forms of zearalenone. The next day, the sample is acidified with H3PO4, extracted with chloroform, and evaporated to dryness. The residue is dissolved in toluene and loaded onto a silica gel cartridge which is washed with toluene and eluted with toluene-acetone (88 + 12). The eluate is evaporated, and the residue is dissolved in chloroform, extracted with 0.18M NaOH, neutralized with H3PO4, and re-extracted with chloroform. The chloroform extract is evaporated, dissolved in mobile phase for LC, and injected onto a normal phase column under the following chromatographic conditions: mobile phase of water-saturated dichloromethane containing 2% 1-propanol, and fluorescence detector, excitation wave-length 236 nm, and 418 nm cut-off emission filter. Recoveries of zearalenone and its metabolites from blood plasma and urine are 80-89% in the range 2.0-10 ng standard/mL plasma, and 81-90% in the range 10-30 ng standard/mL urine. This method was used to analyze blood and urine samples from a pig fed zearalenone-contaminated feed (5 mg/kg), corresponding to 80 micrograms/kg body weight. Zearalenone was rapidly metabolized to alpha-zearalenol, which appeared in the blood only 30 min after feeding. Almost all zearalenone and alpha-zearalenol was found conjugated with glucuronic acid in both blood plasma and urine.
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PMID:Quantitative liquid chromatographic method using fluorescence detection for determining zearalenone and its metabolites in blood plasma and urine. 316 69

15 hazardous industrial waste samples were evaluated for mutagenicity in the Salmonella plate-incorporation assay using strains TA98 and TA100 in the presence and absence of Aroclor 1254-induced rat liver S9. Dichloromethane/methanol extracts of the crude wastes were also evaluated. 7 of the crude wastes were mutagenic, but only 2 of the extracts of these 7 wastes were mutagenic; extracts of 2 additional wastes also were mutagenic. In addition, 10 of the crude wastes were administered by gavage to F-344 rats, and 24-h urine samples were collected. Of the 10 raw urines evaluated, 3 were mutagenic in strain TA98 in the presence of S9 and beta-glucuronidase. The 3 crude wastes that produced these 3 mutagenic urines were, themselves, mutagenic. Adequate volumes of 6 of the 10 raw urines were available for extraction/concentration. These 6 urines were incubated with beta-glucuronidase and eluted through Sep-Pak C18 columns; the methanol eluates of 3 of the urines were mutagenic, and these were the same 3 whose raw urines also were mutagenic. In general, the C18/methanol extraction procedure reduced the cytotoxicity and increased the mutagenic potency of the urines. To our knowledge, this is the first report of the mutagenicity of urine from rodents exposed to hazardous wastes. Based on the present results, the use of only strain TA98 in the presence of S9 might be adequate for general screening of hazardous wastes or waste extracts for genotoxicity. The urinary mutagenesis assay does not appear to be a useful adjunct to the Salmonella assay for screening hazardous wastes. The problems associated with chemically fractionating diverse types of hazardous wastes for bioassay are also discussed.
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PMID:Mutagenicity in salmonella of hazardous wastes and urine from rats fed these wastes. 331 35

We evaluated the biochemical characteristics of endogenous fluorescent substances, Ex 380 nm/Em 440 nm and Ex 400 nm/Em 460 nm, present in sera of patients with chronic renal failure (Clin. Chem. 31:1988, 1985). Sera from 23 patients with chronic renal failure (CRF) and from 10 normal subjects were filtered through ultrafiltration membranes (cutoff limit of 500 Da). Fluorescence intensity of the aforementioned substances was significantly elevated as compared to normals (p less than 0.001). Fluorescence characteristics of these substances remained unaltered after ultrafiltration and treatment with beta-glucuronidase. Extraction of these fluorescent compounds with organic solvents (dichloromethane, ethyl acetate, chloroform:methanol) could not be achieved after ultrafiltrates were subjected to 6N hydrochloric acid (HC1) hydrolysis. In addition, treatment with 6N HC1 enhanced fluorescence intensity without altering fluorescence excitation/emission maxima. Removal of fluorescence could be accomplished in toto by adsorption onto activated charcoal with subsequent recovery from charcoal by treatment with sodium hydroxide, pH 12 (Ex 380 nm: 51.1%, Ex 400 nm: 91.8%). Analysis of alkali-treated specimens by high performance liquid chromatography demonstrated that peptides associated with these fluorescent substances were denatured, although fluorescence at these previously described excitation/emission maxima persisted. Our studies indicate that the unique fluorescence observed in the sera of patients with CRF is not an intrinsic characteristic of a specific peptide or its amino acids, but rather an inherent property of fluorescent molecules which may bind to these peptides.
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PMID:Biochemical elucidation and HPLC fractionation of fluorescent peptides in patients with chronic renal failure. 344 37

A comprehensive high-performance liquid chromatographic method was developed for quantitating propranolol and its known metabolites in serum, bile and urine. Analysis was performed before and after incubation of the samples with beta-glucuronidase-arylsulfatase to quantitate both free and conjugate forms of the oxidative metabolites. Fractionation of the basic, neutral and acidic metabolites was achieved by differential pH solvent extraction. The basic and neutral metabolites were extracted from the biological samples at pH 10.5 with 2% n-butanol in dichloromethane. Additional clean-up of the basic fraction by back-extraction into dilute acid was needed for those samples that were subjected to enzymatic hydrolysis. The original aqueous sample was titrated with acid to pH 1, followed by extraction of the remaining acidic metabolites into either n-butanol-dichloromethane (with unhydrolyzed serum) or carbon tetrachloride (with all other samples). Chromatographic separation of the metabolites in the different extracts was achieved on a reversed-phase C18 column, using a single isocratic mobile phase consisting of 0.044 M pH 2.7 phosphate buffer, tetrahydrofuran, methanol and acetonitrile, with the addition of n-butylamine as a competing base to control retention volume and peak shape. Detection and quantitation of propranolol and its metabolites in the low nanogram to sub-nanogram range was afforded by fluorescence at a low UV excitation wavelength. The coefficients of variation for replicate assay of spiked samples were uniformly less than 6% for all the analytes.
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PMID:Versatile isocratic high-performance liquid chromatographic assay for propranolol and its basic, neutral and acidic metabolites in biological fluids. 357 4

After in vitro perfusion of rabbit isolated liver with an emulsion of perfluorocarbon containing [3H]gitoxin, the radioactivity in the liver and in the bile was the sum of that contained in a volatile fraction (tritiated water due to metabolism of gitoxin) and that contained in a nonvolatile fraction (gitoxin and its metabolites). This fraction was divided, by differential extraction, into two groups: liposoluble (dichloromethane soluble) compounds, including unchanged gitoxin and lipophilic metabolites (amounting to 50% in the liver and to 5% in the bile), and hydrosoluble (dichloromethane insoluble) metabolites (50% in the liver, 95% in the bile). Three types of metabolites were found in the hydrosoluble fraction. One type was sensitive to beta-glucuronidase and arylsulfatase hydrolysis, a second type was insensitive to enzymatic hydrolysis but sensitive to acid hydrolysis, and a third type was insensitive to both enzymatic and acid hydrolysis. The liposoluble compounds and the conjugates sensitive to enzymatic hydrolysis were analyzed by reversed phase high performance liquid chromatography and found to comprise a wide variety of metabolites. The present study demonstrates that gitoxin uptake by the liver is followed by a fast and extensive metabolism to highly polar metabolites that are rapidly excreted into the bile.
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PMID:Hepatic clearance of gitoxin. Metabolism and biliary excretion by rabbit isolated liver. 614 90

The present study was designed to investigate the chemical properties of the aggression-promoting cues present in bladder urine of male mice. The results of the first experiment confirmed earlier work by demonstrating the presence of an aggression-promoting chemosignal in bladder urine. In Experiment 2, behavioral assays were separately performed on the organic and aqueous layers of bladder urine obtained by repeated dichloromethane extractions. Only the combined organic layers of the initial three extractions demonstrated behavioral activity. A fourth extraction showed no behavioral activity for both organic and aqueous layers. However, the findings of Experiment 3 showed that incubation of the aqueous layer from the third CH2Cl2 extraction in beta-glucuronidase can free additional aggression-promoting cues into a subsequent CH2Cl2 extraction. It is concluded that two forms of the aggression-promoting chemosignal are present in bladder urine. One is lipophilic and behaviorally active, whereas the other is conjugated, possessing latent chemosignal properties.
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PMID:beta-Glucuronidase activation of latent aggression-promoting cues in mouse bladder urine. 689 69

A fluorescence high-performance liquid chromatographic method is described for the determination of 17-oxosteroids in biological fluids. 17-Oxosteroids in urine samples are extracted with dichloromethane after enzymatic hydrolysis (beta-glucuronidase-sulfatase), and dehydroepiandrosterone sulfate in serum samples is solvolysed with sulfuric acid in ethyl acetate. 17-Oxosteroids are labeled with dansyl hydrazine in trichloroacetic acid-benzene solution, and then chromatographed on the microparticulate silica gel column using dichloromethane-ethanol-water (400 : 1 : 2) as the mobile phase. The eluate is monitored by a fluorophotometer at 365 nm (excitation) and 505 nm (emission). Linearities of the fluorescence intensities (peak heights) with the amounts of various 17-oxosteroids were obtained between 60 and 1000 pg. The assay proved satisfactory with respect to sensitivity, precision and accuracy. The results obtained by a radioimmunoassay and this method were in good agreement (r = 0.964, n = 81) for serum dehydroepiandrosterone sulfate. This method is also use for the simultaneous determination of individual 17-oxosteroids in serum and urine.
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PMID:Determination of 17-oxosteroids in serum and urine by fluorescence high-performance liquid chromatography using dansyl hydrazine as a pre-labeling reagent. 732 Jan 36

Kinetics and metabolism of 3H-gitoxin were determined in the guinea-pig after the i.v. administration of 80 microgram gitoxin/kg. The time course of plasma concentration and urinary amounts remaining to be excreted were described according to the three-compartment linear body model. Apparent half-lives of 4.98 +/- 0.16 hr (plasma) and 24.0 +/- 0.5 hr (urine) were found according to the CH2Cl2-soluble radioactivity. The apparent volume of central compartment and the apparent volume of distribution were estimated with 0.44 +/- 0.05 l/kg and 14.33 +/- 1.131/kg respectively. During 96 hr, approximatively 5.3% of the radioactivity given were eliminated via the kidneys whereas almost 78.7% were recovered in faeces. In animals with bile-duct cannulated, approximatively 82.6% of the dose given were excreted in bile during 6 hr. The hepatic degradation of gitoxin was so fast that almost 70% of the radioactivity recovered in plasma, urine and bile samples after 2 hr could no longer be extracted by dichloromethane. In the lipophilic extracts diginatin and its derivatives were found as possible metabolites of gitoxin. At least four polar metabolites hardly hydrolysable by beta-glucuronidase and by arylsulfatase were detected by TLC in the aqueous extracts from the gastro-intestinal excretions.
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PMID:Studies on the pharmacokinetics and the metabolism of gitoxin in the guinea-pig: I. Disposition kinetics following an i.v. bolus of 3H-gitoxin. 740


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