Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Serum 3 beta-hydroxy-5-cholenoic acid (3 beta-OH-delta 5) was analyzed in 100 cases (90 patients with hepatobiliary diseases, 10 normal subjects) and its clinical significance investigated. The measurement of 3 beta-OH-delta 5 was performed by high performance liquid chromatography (HPLC) with immobilized 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) as the enzyme column. Esterified 3 beta-OH-delta 5 was measured after enzymatic hydrolysis with sulfatase and beta-glucuronidase. 3 beta-OH-delta 5 was hardly detected in normal cases. On the other hand, serum 3 beta-OH-delta 5 levels were remarkably high in cholestatic cases and also high in other cases with high bilirubin levels. The ratio of glycine- to taurine-conjugates (G/T ratio) was effective in discriminating cholestasis from hepatocellular damage such as in cases of acute hepatitis or fulminant hepatitis. More than 90% of the 3 beta-OH-delta 5, which is toxic, was sulfated or glucuronidated, suggesting detoxification by esterified bile acids. Significant increases of taurine-conjugated 3 beta-OH-delta 5 were observed in cases with pruritus, and a relationship between taurine-conjugated and pruritus was presumed. Therefore, analysis of 3 beta-OH-delta 5 is considered to be effective in clarifying the pathogenesis of hepatobiliary diseases.
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PMID:Clinical evaluation of serum 3 beta-hydroxy-5-cholenoic acid in hepatobiliary diseases. 347 20

Cultures of isolated human hepatocytes from three different human liver specimens were exposed for 24 h to media containing [3H]benzo[a]pyrene (BP) (0.1, 1.0, 10, 100 microM). The cells and media were harvested and extracted. Subsequent incubations of the aqueous phase with beta-glucuronidase and aryl sulfatase, followed by acetone/ethyl acetate extraction, were utilized to determine specific conjugation. Separation of the BP and its metabolites in the residues of the extracts was achieved by h.p.l.c. The capacity of human hepatocytes to metabolize BP was not saturated at up to 100 microM of BP, and the predominant metabolites produced were eluted in the void volume and were a mixture of highly polar BP forms. The next four most prevalent forms of BP metabolites were the 3-hydroxy BP, BP-4,5-dihydrodiol, BP-9,10-dihydrodiol, and BP-7,8-dihydrodiol. These metabolites all increased nearly linearly with dose. Conjugation varied for each different case, ranging from 31 to 91%, but a general trend clearly appeared; if beta-glucuronidation decreased, then sulfation increased and vice versa. BP metabolite binding to DNA was associated with the amount of unconjugated BP-7,8-dihydrodiol metabolite. BP metabolite binding to DNA was nearly linear from 0.1 to 10 microM BP; however, binding to DNA at 100 microM increased 64- to 844-fold over the binding occurring at 10 microM. Thus, human hepatocytes have a strong tendency to form highly polar BP metabolites, and total binding of BP to DNA over a four-log dose range is much less at 0.1-10 microM than one would predict from extrapolation from the high concentration (100 microM).
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PMID:Metabolism of benzo[a]pyrene in primary cultures of human hepatocytes: dose-response over a four-log range. 359 30

Adult male Fisher 344 rats (190-220 g), were given an intravenous dose (10 mg/rat) of BHA. Pretreated and control rats received an intravenous dose of [G-3H] acetaminophen (25 mg/rat). Bile was collected prior to dosing and for 5-6 hours after dosing at varying time intervals. Separate aliquots of 0.2 ml were incubated with beta-glucuronidase and sulfatase, respectively. These incubation mixtures were then extracted and analyzed by reverse phase HPLC. In all cases control animals showed a greater deceleration in the biliary excretion of the water soluble metabolites when compared with pretreated animals. Increases in both glucuronide and sulfate elimination processes are assumed to be contributory, in part, to the overall effect of BHA on acetaminophen metabolism.
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PMID:BHA (2(3)-tert-butyl-4-hydroxyanisole)-mediated modulation of acetaminophen phase II metabolism in vivo in Fisher 344 rats. 362 63

The aim of these two studies was to evaluate the safety and pharmacokinetics of oral nalmefene, a new orally effective opioid antagonist. In the first study, single ascending doses of 50, 100, 200, and 300 mg of nalmefene HCl were administered in double-blind fashion to four groups of healthy men. There were six subjects in each group; four received nalmefene and two received placebo. The drug was well tolerated at all dose levels with only mild and transient side effects, such as lightheadedness, at the higher doses. Model-independent pharmacokinetic analysis of the plasma concentration-time data showed that nalmefene was rapidly absorbed and had an elimination half-life that ranged from seven to 15 hours (mean, 10.7 hr). There was a good linear relationship (r = .97) between administered dose and total area under the curve at each dose level. Only about 4% of the dose was excreted in the urine as unchanged nalmefene, whereas up to 60% was excreted as a beta-glucuronidase/sulfatase hydrolysable conjugate(s) of nalmefene. In the second study, six healthy men were initially administered a single 50-mg dose of drug, and plasma samples were obtained at selected time intervals for 48 hours. A dosing schedule of 20 mg q12h was then started and continued for seven days. Plasma samples were collected immediately before each dose and at selected times for up to 48 hours after the last dose. The drug was well tolerated by all subjects, and no clinically significant adverse effects were observed during the seven-day administration period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nalmefene: safety and kinetics after single and multiple oral doses of a new opioid antagonist. 368 May 80

Di-(2-ethylhexyl)phthalate (DEHP) produced hepatocellular carcinomas in rodents at high doses in a NTP/NCI bioassay. DEHP has not shown evidence of genotoxic activity in in vitro mutagenicity tests. We extended these studies by examining the mutagenicity of urine from rats dosed with DEHP, 2-ethylhexanol (2-EH), and several other 2-EH derived plasticizers, i.e. di-(2-ethylhexyl)adipate (DEHA), di-(2-ethylhexyl)terephthalate (DEHT) and tri-(2-ethylhexyl)trimellitate (TEHT). A modified Ames Salmonella/microsome assay was used to determine mutagenicity. Urine was pooled from male Sprague--Dawley rats dosed daily for 15 days with 2000 mg/kg of each test substance with the exception of 2-EH which was given at 1000 mg/kg. Direct plating procedures were used to determine the presence of mutagens in urine. Urine from rats dosed with 8-hydroxyquinoline was used as a positive control. There was no evidence that mutagenic substances were excreted in the urine by rats dosed with either DEHP, DEHA, DEHT, TEHT or 2-EH as determined in the presence or absence of rat liver microsomes, and with or without treatment with beta-glucuronidase/aryl sulfatase. Our findings indicate that the above test compounds were not converted to urinary metabolites that were mutagenic. These observations provide no evidence for a genotoxic mechanism for DEHP carcinogenicity in rodents.
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PMID:Bacterial mutagenicity testing of urine from rats dosed with 2-ethylhexanol derived plasticizers. 388 74

2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) is a potent bacterial mutagen formed during cooking of beef. IQ was administered intravenously to Sprague-Dawley rats at concentrations ranging from 7.5-50 mg/kg body weight. Urine was collected and analyzed for mutagenicity. Urinary mutagens were found which required activation by S9 mix, and reverted Ames test strains TA98 and TA100, but not TA1535 or TA1537. The amount of urinary mutagen(s) were related to IQ dose administered and were excreted within 48 h. Additional mutagenic activity was not released after incubation with beta-glucuronidase or aryl sulfatase. Analysis of urinary mutagens by HPLC indicates that the majority of mutagenic activity is due to unchanged IQ, but a small peak of mutagenic activity may correspond to N-acetyl or 3-N-demethylated metabolite. Since only 1% of the administered mutagenic activity is recovered in the urine, IQ may be readily detoxified in vivo.
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PMID:Fate of the food mutagen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in Sprague-Dawley rats. I. Mutagens in the urine. 388 29

Saithe (Pollachius virens L.) were starved for 66 days at 10 degrees C and activities of aryl sulfatase, acid proteinase, beta-glucuronidase, RNAase and acid phosphatase measured in homogenates prepared from fast and slow myotomal muscles. In fed fish, hydrolase activities were generally higher in slow than fast muscles. With the exception of acid proteinase activity in slow muscle, the activities of all the lysosomal enzymes increased by 70 to 100% during starvation. In general, there was a proportionally larger increase in the hydrolase activities in fast than in slow muscle. In a second experiment, fish were starved for 74 days, and refed for up to 52 days. The increases in aryl sulfatase and acid proteinase activity produced in fast muscle with starvation were found to be rapidly reversed by refeeding. Lysosomal enzyme activities in fish sampled after 10 days refeeding were not significantly different from fed controls. Membrane fractions enriched in aryl sulfatase activity were prepared from the fast muscle of 66-day starved fish. These were capable of degrading both myosin heavy chains and actin to lower molecular weight peptides at acid (pH 5.0), but not at neutral pH. The results suggest a role for lysosomal enzymes in the breakdown of myofibrillar proteins during starvation.
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PMID:Lysosomal enzyme activities in muscle following starvation and refeeding in the saithe Pollachius virens L. 391 Apr 36

Serial blood samples were drawn from 12 patients undergoing hemodialysis who were receiving tricyclic antidepressants (TCAs). Samples were drawn before, during, and after a dialysis session (two to 17 sessions per subject). Samples were analyzed by HPLC before and after hydrolysis with beta-glucuronidase/sulfatase to determine the conjugated and nonconjugated metabolites. Analysis of these data in comparison with those of controls with depression and normal renal function showed that: (1) at steady state, tertiary and secondary amine TCA levels did not differ; (2) levels of the hydroxylated metabolites had greater variability and were somewhat higher at steady state; (3) levels of the conjugated hydroxylated compounds were markedly elevated, reaching 500% to 1500% normal; (4) the time to reach a steady-state level appeared to be slightly increased; and (5) elimination t1/2 s of unconjugated and conjugated drug forms were longer in our patients with normal renal function than those reported in the literature. Levels of the tertiary, secondary, and hydroxylated metabolites were not changed by dialysis, whereas there were substantial decrements in glucuronidated metabolite levels. These findings demonstrate increased concentrations of conjugated drug forms and suggest an abnormal distribution or delayed elimination of unconjugated and conjugated metabolites. These observations may shed some light on the apparent hypersensitivity of these patients to TCA side effects, particularly because glucuronides may exert peripheral pharmacologic effects.
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PMID:Tricyclic antidepressant and metabolite levels in chronic renal failure. 397 55

Di(2-ethylhexyl)phthalate (DEHP) is extensively used as a plasticizer for vinyl plastic articles. It has been found to be positive in an NCI rodent bioassay but has generally given negative results in in vitro genotoxicity tests. We therefore decided to test the urine of rats fed [14C]DEHP for mutagenic activity in the Ames Salmonella test. The recovery of radioactivity from the urine of rats dosed with [14C]DEHP was examined by solvent extraction and XAD-2 resin absorption procedures. Both of these procedures were inadequate for quantitative recovery of urinary metabolites required for subsequent mutagenicity testing using the Ames Salmonella/microsome procedure. Recoveries of less than 5% were observed using standard solvent extraction techniques whereas the XAD-2 adsorption technique gave about 67% at high resin/urine ratios. Treatment of the urine with beta-glucuronidase/aryl sulfatase did not affect these recoveries. The direct urine plating procedure represents a viable alternative to the above concentration procedures for this phthalate ester. The effects of L-histidine and the beta-glucuronidase/aryl sulfatase preparation on the background reversion frequencies of the Ames tester strains is discussed.
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PMID:Methods for measuring mutagenicity in urine of rats dosed with [14C]di(2-ethylhexyl)phthalate. 397 21

To investigate the modifying role of intestinal microflora in the metabolism of chemical carcinogens in vivo, we subjected bile from Fischer rats treated per os with chemical carcinogens and related compounds to a mutagenicity assay in the presence and absence of a cell-free extract from human feces. A mixture of the bile sample and potassium phosphate buffer was incubated in the presence or absence of human cell-free fecal extract and then further incubated with a bacterial suspension of Salmonella typhimurium tester strains TA98 or TA100. Bile from rats treated with 1-nitropyrene (1-NP) produced about 2700 and 400 revertants per plate in strain TA98 in the presence and absence of the fecal extract, respectively. There was a drug dose- and bile volume-related response. Treatment of 1-NP-bile with beta-glucuronidase, but not aryl sulfatase, enhanced its mutagenicity. Cell-free extracts of some strains of intestinal bacteria (Bacteroides fragilis ATCC 12044, B. vulgatus ATCC 8482, B. thetaiotaomicron ATCC 12290, Bacteroides sp. strain 524, Eubacterium eligens VPI C15-48, Peptostreptococcus sp. strain 204 and Escherichia coli A-5-18) also enhanced the mutagenicity of 1-NP-bile. These bacterial cell-free extracts hydrolyzed the synthetic beta-D-glucuronides of phenolphthalein and/or p-nitrophenol. These data indicate that the glucuronide(s) of 1-NP-metabolite(s) secreted into bile can be hydrolyzed in the intestine by bacterial beta-glucuronidases to potent mutagenic aglycone(s).
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PMID:Mutagenic activation of biliary metabolites of 1-nitropyrene by intestinal microflora. 398 38


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