Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019209 (hepatomegaly)
 5,798 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peroxisome proliferators are a structurally diverse group of chemicals. They include fibrate hypolipidaemic drugs, phthalate ester plasticisers, phenoxy acid herbicides, azole antifungal drugs, and perflurinated fatty acids. This presentation will focus on the common pleiotropic responses produced by these compounds including hepatomegaly (hyperplasia and hypertrophy), activation of cell cycle S-phase ploidy changes, cytochrome P4504A1 induction, morphometric/biochemical analysis of peroxisome proliferation and stimulation of growth factors, and oncogene activation. Consideration will also be given to the role of recently described Peroxisome Proliferator Activated Receptor in these diverse hepatic responses. Peroxisome proliferators are uniformly negative in a wide range of genotoxicity tests, but nevertheless are complete carcinogens, particularly in rodent liver. Mechanisms of nonmutagenic carcinogenesis will be discussed including the active oxygen hypothesis involving 8-hydroxydeoxyguanosine adducts and the possibility of peroxisome proliferators promoting preexisting lesions by clonal expansion, eventually resulting in frank tumorigenesis. Finally, a consideration of the risk assessment of peroxisome proliferation to humans will be discussed.
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PMID:Peroxisome proliferators: paradigms and prospects. 839 Jul 28

The role of reactive oxygen species in liver fibrogenesis is not yet clarified. The aim of this study was to investigate oxidative-stress-related changes in cirrhotic rats. Cirrhosis was induced by bile duct ligation in Sprague-Dawley rats. Plasma malondialdehyde (MDA), hepatic 8-hydroxy-2'-deoxyguanosine (8-OHdG), hepatic mitochondrial respiratory functions and gene transcripts were measured at 2 and 4 weeks after surgery in bile-duct-ligated (BDL) and sham-operated-operated rats. The results showed progressive increases in the levels of plasma MDA, hepatic 8-OHdG and procollagen I and III mRNA expression, and progressive impairment of hepatic mitochondrial respiratory function in BDL rats at 2 and 4 weeks after ligation compared with sham-operated rats. Moreover, at 4 weeks after ligation, BDL rats exhibited reduced plasma glutathione and vitamin E levels, impaired hepatic mitochondrial electron transport enzyme activities and oxidative phosphorylation function. In addition, hepatic mRNA expression of transforming growth factor-beta1 was increased. Hepatomegaly, abnormal plasma alanine transaminase and aspartate transaminase levels, and portal hypertension were noted in BDL rats. Our results suggest that bile duct ligation in the rat induces mitochondrial dysfunction and biochemical and molecular changes related to oxidative stress in the liver.
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PMID:Oxidative-stress-related changes in the livers of bile-duct-ligated rats. 1259 53

Previous reports have proposed that reactive oxygen species resulting from induction of cytochrome P450 (CYP) isozymes might be involved in the modes of action of hepatocarcinogens with CYP-inducible potency. In the present study, we investigated 8-hydroxydeoxyguanosine (8-OHdG) levels, in vivo mutagenicity and glutathione S-transferase placental form (GST-P)-positive foci in the livers of gpt delta rats treated with piperonyl butoxide (PBO) or phenobarbital (PhB) for 4 and 13 weeks. Significant elevations in Cyp 1A1 and Cyp 1A2 mRNA levels after PBO treatment, and in Cyp 2B1 mRNA levels after PBO or PhB treatment, appeared together with remarkable hepatomegaly through the experimental period. Time-dependent and statistically significant increases in 8-OHdG levels were observed in the PBO treatment group along with significant increases in proliferating cell nuclear antigen (PCNA)-positive hepatocytes at 4 weeks, while no increase in 8-OHdG levels was found in PhB-treated rats. No changes in mutant frequencies of gpt and red/gam (Spi(-)) genes in liver DNA from PBO- or PhB-treated rats were observed at 4 or 13 weeks. A 13-week exposure to either PBO or PhB did not affect the number and area of GST-P-positive hepatocytes. CYP 1A1 and 1A2 induction may be responsible for elevated levels of 8-OHdG in PBO-treated rats. However, neither GC:TA transversions nor deletion mutations, typically regarded as 8-OHdG-related mutations, were observed in any of the treated rats. We conclude that reactive oxygen species, possibly produced through CYP catalytic pathways, likely induced genomic DNA damage but did not give rise to permanent gene mutation.
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PMID:Oxidative DNA damage and reporter gene mutation in the livers of gpt delta rats given non-genotoxic hepatocarcinogens with cytochrome P450-inducible potency. 2073 35