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

The antiprotozoal drug pentamidine [1,5-bis(4'-amidinophenoxy)pentane] has been previously shown to be metabolized by rat liver microsomes, and five of the seven putative primary metabolites have been identified. With the synthesis and identification of 5-(4'-amidinophenoxy)pentanoic acid and 5-(4'-amidinophenoxy)-1-pentanol as the remaining two metabolites, the primary metabolism of pentamidine in rats appears fully characterized. Use of [14C]pentamidine with rat liver microsomes confirms this conclusion, since no unidentified radioactive peaks were detected by high-performance liquid chromatography (HPLC). Isolated, perfused rat livers were used with [14C]pentamidine to identify secondary metabolites. Only two novel radioactive peaks were detected by HPLC analysis of perfused liver samples. The treatment of liver samples with sulfatase or beta-glucuronidase resulted in the reduction or elimination of these peaks and gave rise to peaks identified as para-hydroxybenzamidine and 5-(4'-amidinophenoxy)pentanoic acid. It was concluded from these results that only these two primary metabolites were conjugated with sulfate or glucuronic acid. After 4 h of incubation in the perfused liver system, approximately 15% of the recovered radiolabel was pentamidine. These results suggest that pentamidine metabolism can be rapid and extensive in rats.
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PMID:Primary and secondary metabolism of pentamidine by rats. 141 74

We developed a high-performance liquid chromatography (HPLC) method for quantitating p-hydroxy-N-benzylamphetamine glucuronide (pHBAG) and p-hydroxy-benzphetamine glucuronide (pHBZG), which are urinary metabolites of benzphetamine, in humans. Urine samples were hydrolysed with beta-glucuronidase (EC 3.2.1.31) at 37 degrees C overnight and the treated urine was applied to a solid phase extraction column. After washing the column with water, 0.01 mol/L acetic acid and methanol, pHBA and pHBZ were eluted with dichloromethane:isopropanol:28% ammonium hydroxide (78.4:19.6:2.0 v/v). The eluate was evaporated and the residue was dissolved in acetonitrile: 5 mmol/L 1-pentane sulphonic acid (5:95 v/v) and analysed by HPLC with gradient elution. The amounts of urinary pHBAG and pHBZG excreted by two human subjects after oral administration of 10 mg benzphetamine hydrochloride were determined. About 10-15% of benzphetamine was found to be excreted as pHBAG and pHBZG, and almost all of these metabolites were excreted within 24 h. Urine samples should be collected as early as possible after ingestion of benzphetamine to detect pHBAG and pHBZG.
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PMID:Development of a method for the quantitation of benzphetamine metabolites in human urine by high-performance liquid chromatography. 983 92

The stability of testosterone glucuronide (TG), epitestosterone glucuronide (EG) and the T/E ratio in urine has been studied. Samples were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Urine samples were submitted to a solid-liquid cleanup followed by extraction of unconjugated testosterone (T) and epitestosterone (E) with tert-butyl methyl ether (free fraction). The remaining aqueous phase was hydrolyzed with beta-glucuronidase and extracted at alkaline pH with n-pentane. Analytes were analyzed by GC/MS as their enol-trimethylsilyl (TMS) derivatives. The urine for stability testing was obtained from an excretion study after the administration of T to healthy volunteers. The homogeneity of the sample was verified before starting the stability study. The stability of TG and EG was evaluated at different storage conditions. For long-term stability testing, analyte concentration in urine stored at 4 degrees C and -20 degrees C was determined at different time intervals for 22 months. For short-term stability testing, analyte concentration was evaluated in urine stored at 37 degrees C for 3 and 7 days. The effect of repeated freezing (at -20 degrees C) and thawing (at room temperature) was studied for up to three cycles. Data obtained in this work demonstrated the stability of TG, EG and the T/E ratio in sterilized urine samples stored at 4 and -20 degrees C for 22 months and after going through repeated freeze/thaw cycles. Decreases in concentration were observed after 7 days of storage at 37 degrees C due to the partial cleavage of the glucuronide conjugates; however, the T/E ratio was not affected. These results show the feasibility of preparing reference materials containing TG and EG to be used for quality control purposes.
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PMID:Stability studies of testosterone and epitestosterone glucuronides in urine. 1647 May 78