Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oltipraz is a cancer chemopreventive agent active against a wide variety of chemical carcinogens. In spite of the intense chemoprevention and toxicology studies on oltipraz, no information is available on its antifibrotic efficacy. In the present study, the effects of oltipraz on dimethylnitrosamine (DMN)-induced liver fibrogenesis were assessed in rats. As part of mechanistic studies, the expression of transforming growth factor-beta1 (TGF-beta1) and tumor necrosis factor-alpha (TNF-alpha) was monitored. Treatment of rats with DMN (10 microl/kg body weight, i.p., three times per week for 4 weeks) resulted in marked increases in plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (gamma-GT) activities. DMN also caused an increase in the plasma bilirubin content, whereas total plasma protein and albumin levels were rather decreased. Oltipraz (50 mg/kg body weight, p.o., three times per week for 4 weeks) inhibited the increases in plasma ALT, AST, gamma-GT and bilirubin by DMN. DMN increased liver fibrosis as histopathologically assessed by Van Gieson's staining and Masson's trichrome staining (fibrosis score, 3.7; Knodell score, 16), which was reduced by oltipraz treatment (fibrosis score, 2.5; Knodell score, 8.0). Reverse transcription-polymerase chain reaction analysis revealed that oltipraz inhibited an increase in the TGF-beta1 mRNA by DMN. Oltipraz was also active in reducing the production of plasma TNF-alpha by DMN or lipopolysaccharide (LPS), which would contribute to its cytoprotective effect. These results demonstrated that oltipraz inhibited hepatocyte injury and impairment of liver function induced by DMN, and reduces DMN-induced liver fibrosis possibly through suppression of TGF-beta1 and TNF-alpha production.
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PMID:Inhibition of dimethylnitrosamine-induced liver fibrosis by [5-(2-pyrazinyl)-4-methyl-1,2-dithiol-3-thione] (oltipraz) in rats: suppression of transforming growth factor-beta1 and tumor necrosis factor-alpha expression. 1180 29

Oltipraz, developed as an antischistosomal agent, protects against the hepatotoxicity of many xenobiotics and is known to be an effective inhibitor of experimental carcinogenesis in rodents. In the present study, we investigated its effects on the development of lesions in LEC rats, established as a mutant strain characterized by a hereditary predisposition for hepatic damage with severe jaundice. A total of 35 male 6-week-old LEC rats were divided into 2 groups, one administered diet supplemented with oltipraz at a dose of 400 ppm, and the other fed basal diet alone. Animals in each group were sequentially sacrificed at 10, 15, and 25 weeks after commencement of the oltipraz administration. Eight animals died or became moribund in the oltipraz group during weeks 10 and 11 of the treatment, whereas only one rat in the nontreatment group died after 16 weeks. All dead or moribund animals showed severe or moderate jaundice. The treatment caused a decrease in body weight gain from 9 to 13 weeks, and an increase in relative liver weight at each sacrifice point. Serum biochemical assays performed at week 25 revealed elevated levels of serum AST, ALT, LDH, ALP, gamma-GTP, and Cu in the treated-animals. The glutathione level in the livers of oltipraz-treated animals was significantly higher than that in the control rats. Histopathologically, enlarged hepatocytes with large nuclei, focal necrosis, pigment granule-laden Kupffer cells and hypertrophy of renal tubule cells were observed in both groups, but the severity of these changes was greater in the oltipraz group. Our results thus indicate that spontaneous hepatic damage in LEC rats is enhanced by oltipraz, by a mechanism that remains to be elucidated.
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PMID:Enhancing effects of oltipraz on the development of spontaneous hepatic lesions in LEC rats. 1195 Jan 60

Liver fibrosis is a prepathological state wherein damaged liver tissues in chronic liver diseases, such as hepatitis, are not repaired to normal tissues, but converted to fibrous tissue. 5-(2-Pyrazinyl)-4-methyl-1,2-dithiol-3-thione (oltipraz), a cancer chemopreventive agent, is effective against a wide variety of chemical carcinogens. Recently, we reported that oltipraz inhibits liver fibrogenesis (Kang et al., 2002). In the present study, the effects of oltipraz in combination with dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate (DDB) on dimethylnitrosamine (DMN)-induced liver fibrogenesis were assessed in rats. Oltipraz (30 mg/kg body weight, p.o., 3 times per week for 4 weeks) was found to inhibit the increases in plasma ALT, AST and bilirubin by DMN, whereas DDB (30 mg/kg body weight, p.o., 3 times per week for 4 weeks) attenuated the increases in the plasma ALT and bilirubin. The lowered plasma protein and albumin contents in DMN-treated rats were completely restored by oltipraz, but not by DDB. DDB decreases liver cell injury and inflammation through inhibition of nuclear factor-kB. DMN increased the accumulation of liver collagen, as indicated by the increase in the 4-hydroxyproline content in liver homogenates, which was reduced by treatment with oltipraz, but not by DDB. Given the differential effect between oltipraz and DDB, the potential enhancement of antifibrotic efficacy by the drugs was assessed in the animal model. Despite the minimal effect of DDB on DMN-induced fibrogenesis, DDB (5-25 mg/kg), administered together with oltipraz (25-5 mg/kg), showed an additive protective effect against hepatotoxicity and fibrosis induced by DMN, which was shown by the blood chemistry parameters and histopathological analysis. The adequate composition ratio of oltipraz to DDB was 5:1. These results provide information on the pharmaceutical composition, comprising of oltipraz and DDB as the active components, for the treatment and/or prevention of liver fibrosis and cirrhosis.
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PMID:The anti-fibrogenic effect of a pharmaceutical composition of [5-(2-pyrazinyl)-4-methyl-1,2-dithiol-3-thione] (oltipraz) and dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate (DDB). 1243 1