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)

In order to clarify the action of drugs for liver disease, the effect of protoporphyrin (PP) on CCl4-induced liver injury was studied. Attention was given to the levels of lysosomal enzymes, some components of the liver, and inhibition of enzymes and lysis of lysosomal membranes by lipid peroxides. Administration of PP to CCl4-poisoned rats was found to prevent the decrease in lysosomal lipolytic enzyme level in the liver, but not in other enzyme levels tested. The inhibition of lipolytic enzyme by CCl4 administered may be partially involved in lipid accumulation in the liver. A dose of PP administered to CCl4-poisoned rats for 8 days depressed the neutral lipid content in the liver nearly to the control value. Methyl linoleate hydroperoxide (hydroperoxide) at a lower concentration of 10(-6)% inhibited the lipolytic enzyme acitivity by 30% and in concentrations ranging from 10(-4) to 10(-3)% inhibited beta-glucuronidase activity. Addition of PP to the medium containing 10(-6) to 10(-5)% hydroperoxide and alpha-tocopherol reduced the enzyme inhibition further than in the absence of PP. The hydroperoxide in concentrations varying from 10(-6) to 10(-3)% caused a partial lysis of liver lysosomal membranes, but addition of PP slightly reduced the damage by the hydroperoxide in concentration lower than 10(-5)%.
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PMID:Effect of "drugs for liver disease" on hepatotoxic action of carbon tetrachloride. I. Changes of lysosomal enzyme levels and effect of protoporphyrin on the levels. 17 10

Lysosome are subcellular particles in which several acid hydrolases of various specificities are localized. The role of lysosome in cellular physiology and pathology has drawn considerable recent attention by several groups of investigators. The purpose of this study was to investigate the activities of lysosomal enzymes--acid phosphatase, beta-glucuronidase, N-acetyl-beta-glucosaminidase--in hepatic disorders. 1) The serum levels of beta-glucuronidase and N-acetyl-beta-glucosaminidase were significantly elevated in patients with diseases of the hepatobiliary system. 2) N-acetyl-beta-glucosaminidase activity in urine specimens from patients with diseases of the hepatobiliary system was found to be significantly higher than in urine specimens from normal adults. 3) Male albino rats of 150 approximately 200 g body weight were used. CCl4 was injected intraperitoneally (dose 0.1 ml of CCl4 per 100 g body weight twice a week for eight weeks). The free activities of lysosomal enzyme were increased and high free/total activity ratios were found in the liver lysosomal fraction of CCl4 intoxicated rats. The results of these experiment indicated that the membranes of lysosome were more permeable to their enzymes, and the release of these enzymes were found in the experimental fatty liver by CCl4. 4) Corticosteroids and chloroquine stabilized rat liver lysosome in vitro from the labilizing influence of incubation at 37 degrees C. 5) The administration of chloroquine to CCl4 intoxicated rats did not cause any well-expressed stabilization of lysosomes. 6) When alpha-Tocopherol was administrated to CCl4 intoxicated rats, the decrease of bound activity and increase of free activity in lysosomal fraction, and increase of acid hydrolases, GOT and GPT in serum were inhibited.
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PMID:[Studies on lysosomes in hepatic disorders (author's transl)]. 48

14C-labelled 3,4-benzpyrene (14C-BP) in dose of 100 mug/animal was injected into female Sprague-Dawley rats under urethane anesthesia. The rats were cannulated at the duct and the output of metabolites in the bile was determined. Non-treated rats excreted 35.5% of the given dose within one hr. The main metabolites excreted in bile were fractionated chromatographically into three. One of these was a metabolite which was hydrolyzed by beta-glucuronidase, the other two were unknown substances. Unchanged BP was not detected. In rats pretreated with CCl4 (0.5 ml/kg, p.o.) 24 hr before experiment, the biliary excretion of BP-metabolites was found to be reduced, that is only 10% of the given dose was excreted within one hr. It was noted that the output within the first 90 min after injection of BP was significantly reduced. In the CCl4-treated rats, bile flow was found to be lowered. However, the reduced output of BP-metabolites was considered not as the result of lowered bile flow, but as the result of disturbance of BP-metabolism in the liver. Thus it is suggested that impaired hepatic junction as the result of CCl4 intoxication may last for more than two weeks, when the hepatic junction is evaluated in terms of biliary excretion of BP.
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PMID:[Effect of carbon tetrachloride on biliary excretion of 3,4-benzpyrene in rats]. 123 18

Lipid peroxidation and loss of enzymes located predominantly in either periportal or centrilobular hepatocytes were investigated in precision-cut liver slices from male Sprague-Dawley rats. Pretreatment of animals with 80 mg/kg phenobarbital for the site-specific enzyme studies enhanced and accelerated CCl4 toxicity in slices resulting from increased radical formation. Liver slices were exposed to 0.57 mM CCl4 by vaporization using a roller incubation system at 37 degrees C for a total of 9 hr. Conjugated diene formation, an index of lipid peroxidation, was detected 15 min following CCl4 administration and increased over time. Loss of cytochrome P450 occurred in a time-dependent manner relative to controls where levels in treated slices were 42% of controls at 9 hr. A 48-hr fast prior to termination increased intracellular K+ leakage relative to that present in slices from fed animals. Significant leakage of glucose-6-phosphate dehydrogenase and beta-glucuronidase from centrilobular hepatocytes occurred 9 hr following CCl4 administration. The content of the periportal enzymes (lactate dehydrogenase and sorbitol dehydrogenase) was unchanged in the same slices over the duration of the experiment. Reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide, a mitochondrial selective dye and indicator of viability, was significantly lower in treated slices from phenobarbital-treated animals at 9 hr relative to controls. These studies demonstrate that precision-cut slices are an ideal in vitro system for mechanistic studies and the investigation of site-specific toxicants since the integral architecture of the liver and cellular identity are maintained.
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PMID:Further examination of the selective toxicity of CCl4 in rat liver slices. 173 51

Two methods of inducing liver cirrhosis in the rat were studied. Intragastric administration of CCl4 for 16 weeks according to Proctor and Chatamra was compared to the administration of thioacetamide in the drinking water (0.3 g/l) for the same period. CCl4 administration induced micronodular cirrhosis in 6/8 animals with a 27% mortality. Thioacetamide induced cirrhosis in 6/8 animals without mortality. The histologic pictures differed somewhat in that the CCl4 group exhibited more necrosis and cellular swelling while the thioacetamide group had more nuclear atypias and proliferation. Biochemically both groups had elevated plasma levels of aspartate aminotransferase. The lysosomal enzyme beta-hexosaminidase (beta-NAG) showed a transient increase in the thioacetamide animals, while beta-glucuronidase decreased. CCl4-induced cirrhosis led to an increase in beta-NAG. Plasma zinc decreased in both groups as well as liver zinc content in the CCl4 group, while there was a continuous elevation of liver zinc in the thioacetamide group. We conclude that oral administration of thioacetamide is a simple and reliable method of inducing experimental liver cirrhosis. The differences in histological appearances and some biochemical parameters may be caused by the different mechanisms of action of thioacetamide and CCl4.
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PMID:Thioacetamide- and carbon tetrachloride-induced liver cirrhosis. 276 88

To study the relationship between lipid peroxidation (LPO) and the release of lysosomal enzymes as markers of liver injury three compounds were chosen which evoke lipid peroxidation (cumene hydroperoxide, CHP), hepatocellular injury (thioacetamide, TAA) or both (carbon tetrachloride, CCl4). Premitochondrial supernatants of phenobarbital-induced rat liver homogenates were incubated in the presence of either agent and an NADPH-regenerating system. Then, lipid peroxidation was assessed by measurement of malondialdehyde (MDA) formation and, after centrifugation at 105 000 g, released beta-glucuronidase was measured in the supernatant. While CCl4 and CHP promoted both events in a time and concentration dependent manner, TAA did not evoke either LPO or lysosomal enzyme release. Glutathione, dithiocarb and (+)-catechin inhibited both effects. Though LPO and lysosomal enzyme release proved to be related events, no strict correlation with the hepatotoxicity was found.
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PMID:Interrelation between lipid peroxidation and lysosomal enzyme release in the presence of carbon tetrachloride, cumene hydroperoxide or thioacetamide. 630 41

Changes in activities of a new proteinase cathepsin T as well as some other lysosomal acid proteinases and hydrolases were examined in liver homogenate from rats treated with a single hepatotoxic dose of carbon tetrachloride. The most striking changes were several-fold increases of liver cathepsin T and D activities over their levels in untreated rats 3 days after administration of the agent to rats. Increase of cathepsin T was greater than that of cathepsin D at all doses of the hepatotoxin examined. The activities of N alpha-benzoyl-DL-arginine 2-naphthylamide hydrolase, acid phosphatase, beta-galactosidase and beta-glucuronidase in poisoned rat liver were unchanged or only slightly increased. Cathepsin T and D activities were less enhanced in mitochondrial lysosomal fractions than in the homogenate, and were greatly elevated in the supernatant fractions of liver from the treated rats. As judged from the molecular weights, the elevated activities of cathepsins T and D in the treated rat liver could be attributable to the two cathepsins themselves and not to other proteinases. Administration to rats of other hepatotoxic agents, thioacetamide and dimethylnitrosamine, also induced the elevation of the two cathepsin activities in liver, but on partial hepatectomy the activities of liver cathepsins T and D did not show such marked increases. Nonparenchymal liver cell fractions were responsible for almost all the increased activities of liver cathepsins T and D. It is possible that cathepsins T and D play a role in the heterolytic breakdown of hepatocyte molecules following CCl4 poisoning.
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PMID:Increased activities of liver cathepsins T and D in carbon tetrachloride-treated rats. 649 24

The authors examined the damage of lysosomal membrane caused by acute CCl4 intoxication by in vitro methods. They measured the acid phosphatase as well as beta-glucuronidase enzyme levels and determined the rate of release of these two enzymes. The in vivo changes in enzyme activity were extrapolated from the in vitro results. The CCl4 causes a significant increase in the permeability and rigidity of the lysosomal membrane. By oral and/or intraperitoneal administration of MTDQ the state of permeability can be improved or even corrected. On the basis of their results, the authors conclude that the lysosomal damage caused by CCl4 is mediated by peroxidation of lipids and the lysosomal membrane can be stabilised by MTDQ.
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PMID:Acute carbon tetrachloride induced lysosomal membrane damage and the membrane protecting effect of a new dihydroquinoline-type antioxidant. 716 3

Effects of single doses of kumari asav, kumari kalp, arogyavardhini and tamra bhasma on lysosomal enzymes (acid phosphatase and beta-glucuronidase) of rat liver and kidney were studied during hepatitis induced by single 0.3 ml/kg body wt dose of CCl4. Histologically all the drugs showed significant hepatoprotection. While acid phosphatase activities of liver and kidney were suppressed, activities of beta-glucuronidase were enhanced by these drugs. The results indicate that acid phosphatase and beta-glucuronidase behave differently, although they are lysosomal in nature.
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PMID:Effect of hepatoprotective ayurvedic drugs on lysosomal enzymes during hepatic injury induced by single dose of CCl4. 792 26

Silymarin, a commercial crude drug used as a hepatoprotective, was found to inhibit 53% of beta-glucuronidase activity at a final concentration of 0.8 mg/ml. Of three compounds A, silybin and C, which were isolated from silymarin, A and silybin potently inhibited the enzyme activity, followed by C. beta-Glucuronidases of intestinal bacteria, HGU-1 and HGU-2, and E. coli HB101 were noncompetitively inhibited by silybin. beta-Glucuronidase of the feces of a healthy human and of a human with colon cancer were also inhibited by silybin, silymarin and saccharic acid 1,4-lactone at 0.03-0.15 mg/ml. Silymarin and silybin protected the increase in enzyme activity in the serum of the rats treated with CCl4.
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PMID:Silymarin and its components are inhibitors of beta-glucuronidase. 801 14


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