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)

The metabolism of 14C-labelled 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) was studied in suspensions of hepatocytes isolated from PCB-pretreated rats. The metabolites found after incubation of IQ/MeIQ (0.1 mM) with PCB-pretreated hepatocytes for 3 h were separated into three principal groups: ethyl acetate-extractable metabolites (2-4%), water soluble metabolites (94-98%) and covalently bound metabolites (0.4-0.5%). The water soluble metabolites were separated by HPLC. The metabolites were evaluated by beta-glucuronidase lability, sulphate incorporation and compared with glucuronides formed by microsomes. Mass spectroscopy and proton NMR were also run. The major metabolites formed were a N2-sulphamate, an O-sulphate in position 5 for IQ and 5 for MeIQ and an O-glucuronide in the same position. The MeIQ N2-sulphamate was much less abundant than the IQ N2-sulphamate. When compared with hepatocytes from uninduced rats, it was found that primarily the formation of ring-hydroxylated conjugates increased after PCB-pretreatment. The major ethyl acetate-extractable metabolites were the N2-acetyl derivatives and an unidentified metabolite. A small peak representing the 5-hydroxy-IQ or 5-hydroxy-MeIQ could also be seen in the HPLC chromatogram of the ethyl acetate extractable metabolites. All major water soluble products described in hepatocytes were also found in urine and bile of uninduced rats exposed to IQ/MeIQ in vivo.
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PMID:Characterisation of metabolites of the food mutagens 2-amino-3-methylimidazo[4,5-f]quinoline and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline formed after incubation with isolated rat liver cells. 251 Sep 46

The dietary addition of several xenobiotics, such as PCB, DDT, aminopyrine, chloretone, BHT and BHA, caused significant increases in the ascorbic acid in urine and liver of rats. The administration of all types of xenobiotics used in the present experiments increased the activity of hepatic UDP-glucose dehydrogenase (1.3-2.8-fold), and the administration of PCB, DDT, BHT or BHA significantly increased the activity of hepatic UDP-glucuronyl transferase (2.2-13.1-fold). The activity of beta-glucuronidase was slightly increased with feeding of PCB, DDT, chloretone or aminopyrine. However, the activity of hepatic UDP-glucuronic acid pyrophosphatase, the conversion of D-glucuronic acid or D-glucuronolactone into L-ascorbic acid and the activity of hepatic L-gulonolactone oxidase did not increase with the administration of PCB or DDT. It is suggested that the increases in the activities of UDP-glucose dehydrogenase and UDP-glucuronyl transferase would have a major role in the stimulation of ascorbic acid synthesis in xenobiotic treated rats.
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PMID:Effect of several xenobiotics on the activities of enzymes affecting ascorbic acid synthesis in rats. 613 23

Lysosomes are subcellular organelles bounded by a semipermeable lipoprotein membrane that contain a battery of hydrolytic enzymes that are collectively capable of degrading all classes of indogenous and exogenous macromolecules. Lysosomes accumulate a diverse range of chemical contaminants which can lead to membrane damage resulting in leakage of their contents into the cytosol and damage to cells. Total lysosomal activity for two acid hydrolases, N-acetyl-beta-D-hexosaminidase and beta-glucuronidase, with different substrate specificities was determined histochemically in digestive gland sections of mussels, Mytilus galloprovincialis from a series of sites in the Venice Lagoon and the Adriatic Sea and correlated, using multi-stepwise regression analysis, with tissue contaminant burdens in order to explore causality. The results indicated that whilst activity of N-acetyl-beta-D-hexosaminidase correlated with body burdens of mercury, beta-glucuronidase, by contrast, correlated with DDT, Arochlor 1254 and eight PCB congeners in combination with iron or zinc.
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PMID:The influence of environmental contaminants on lysosomal activity in the digestive cells of mussels (Mytilus galloprovincialis) from the Venice Lagoon. 1068 15