Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.16.3.1 (ceruloplasmin)
 5,074 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The LEC rat is an inbred mutant strain with spontaneous hepatitis isolated from Long-Evans rats. Since approximately 40% of LEC rats die of fulminant hepatitis, the rat serves an animal model for studying the pathogenesis and treatment of human fulminant hepatitis. The remaining 60% of LEC rats survive and develop chronic (prolonged) hepatitis and subsequently develop liver cancer. Therefore, the LEC rat serves an important animal model for studying the significance of chronic hepatitis in the development of human liver cancer, which often develops in association with chronic hepatitis. The LEC rat can also be used as an animal model of Wilson's disease, since recent studies have disclosed high copper accumulation in the liver and low ceruloplasmin concentration in the serum of this mutant rat.
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PMID:The LEC rat: a model for human hepatitis, liver cancer, and much more. 829 9

Copper (Cu) accumulating bound to metallothionein (MT) in the liver of LEC (Long-Evans with cinnamon-like coat color) rats due to a hereditary metabolic disorder is assumed to lead to acute hepatitis with severe jaundice. The metal was shown to be present in the liver in a form not bound to MT at the beginning of hepatitis after first delivery and lactation. Following this change in the distribution of Cu from MT-bound to non-MT bound form in the liver, changes in the concentrations and distributions of Cu, zinc (Zn) and iron in the plasma and kidneys of LEC rats were also observed. Cu plasma distribution on a gel filtration column by HPLC-ICP revealed that the holo-form of ceruloplasmin (Cp) was present before hepatitis and increased with its development, indicating the availability of Cu for Cp by hepatitis. Cu-binding proteins migrating at the same retention times as those of hepatic Cu-MT and Cu,Zn-superoxide dismutase (SOD) were detected in plasma during hepatitis. Albumin was largely present in the form of nonmercaptoalbumin, reflecting that the bloodstream was under oxidative stress. A sudden increase in the concentration of Cu in the kidneys occurred with hepatitis, and the metal came to be distributed more to high molecular weight proteins with its development.
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PMID:Changes in copper distribution in the plasma and kidneys of LEC rats following acute hepatitis. 830 90

Disordered copper (Cu) metabolism in LEC rats, an animal model of Wilson disease, was characterized by specifying Cu in the liver, bloodstream and kidneys during the accumulation process and at the onset of jaundice; Cu accumulates in the liver with age in a form bound to metallothionein (MT). Massive Cu is liberated from MT when Cu accumulates beyond the capacity of MT synthesis. Cu bound to MT is not supplied to ceruloplasmin (Cp) during its maturation process, while the metal is transferred to Cu,zinc (Zn)-superoxide dismutase (SOD) directly from MT. Cu ions not bound to MT are transferred to Cp and the holo-Cp is excreted into the bloodstream near and at the onset of jaundice. Cu accumulated in the liver in a form bound to MT is removed selectively by tetrathiomolybdate (TTM), and the animal at the beginning of the onset of jaundice recovers by the chelation therapy. Mechanisms of the removal reaction were proposed to involve formation of MT/TTM, Cu/TTM, and/or polymeric Cu/TTM complexes according to the stoichiometry of TTM to Cu. The Cu/TTM complex was assumed to be effluxed into the bloodstream and to bind specifically to albumin. TTM is taken up by the liver in accordance with the Cu content. The toxicity of Cu was explained by the active oxygen species produced in Cu-mediated reactions, and the participation of MT.
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PMID:Disordered copper metabolism in LEC rats, an animal model of Wilson disease: roles of metallothionein. 855 76

The possible relation of the increase in the concentration of copper (Cu) in the bloodstream with the increased supply of Cu to ceruloplasmin in the liver was examined in relation to the onset of jaundice in Long-Evans rats with a cinnamon-like coat color (LEC rats), an animal model of Wilson disease. The Cu concentration in serum and that in liver, and then that in kidneys of LEC rats were correlated, and then the relationship between the Cu concentration in serum and the malondialdehyde (MDA) concentration in the liver, a marker for lipid peroxidation, and also the activities of alanine aminotransferase and lactate dehydrogenase, marker enzymes for liver damage, were examined. An increase in the Cu concentration in liver induced significant increases in the Cu concentrations in serum and kidneys, and their relationship was different before and after the onset of jaundice, as reflected by the concentration of Cu in serum (lower than 1.5 and higher than 2.7 micrograms/ml, respectively). The relationship between the MDA concentration in liver and the Cu concentration in serum showed a characteristic change between before and after the onset of jaundice. The marker enzymes for liver damage increased significantly with age, and showed distinct responses at the Cu concentration of 1.5-2.7 micrograms/ml in serum. The results suggest that the Cu concentration in plasma reflects the on-going biological and toxicological actions of non-MT-bound Cu in the livers of LEC rats.
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PMID:Copper in plasma reflects its status and subsequent toxicity in the liver of LEC rats. 948 27

In patients with Wilson's disease, both copper incorporation into ceruloplasmin and excretion of this metal into bile are impaired. These conditions are caused by a genetic defect in the Wilson's disease gene (ATP7B). To investigate the Wilson's disease gene protein (ATPase7B) in hepatocytes, we constructed an expression plasmid carrying full-length complementary DNA for human Wilson's disease gene and attempted to express the gene in hepatocytes of LEC rats, an animal model of Wilson's disease. Transfection of hepatocytes, either in vitro or in vivo, was done using a newly developed cationic liposome containing 1,4-bis(3-(N-hexadecyl) aminopropyl) piperazine. Immunological analyses of human ATPase7B with specific monoclonal antibodies showed human ATPase7B to be a membrane protein with a molecular mass of 155 kd. Analysis of human ATPase7B expressed in hepatocytes from LEC rats suggested that this protein is present in the trans-Golgi network and at the plasma membrane, a distribution pattern similar to that of Menkes' disease protein (ATPase7A). These findings suggest that these two putative copper-transporting P-type ATPases function similarly at the cellular level. Cotransfection and coexpression of the human Wilson's disease gene and ceruloplasmin gene in cultured hepatocytes indicate that the distribution of ceruloplasmin is always accompanied by ATPase7B at the perinuclear region, but that part of ATPase7B localizes irrespective of the distribution of ceruloplasmin. Based on these investigations, we propose that ATPase7B exists in the trans-Golgi network and transports copper into this compartment. This seems to ensure an appropriate delivery of copper to the apoceruloplasmin. On the other hand, part of ATPase7B that is not accompanied by ceruloplasmin in the perinuclear region and at the plasma membrane seems to contribute to efflux of this metal from the hepatocytes. Thus the distribution patterns of ATPase7B in hepatocytes may explain the dual roles of this P-type ATPase in hepatocytes.
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PMID:Intracellular distribution of the Wilson's disease gene product (ATPase7B) after in vitro and in vivo exogenous expression in hepatocytes from the LEC rat, an animal model of Wilson's disease. 950 Jul 10

Most of copper present in rat plasma and liver binds to caeruloplasmin and metallothionein, respectively, and is not redox active. However, free forms of copper including loosely bound forms to other molecules are redox active. We assessed the free copper in Long-Evans rats with a cinnamon-like coat color (LEC rats), an animal model of Wilson disease and liver cancer. Compared to those of control rats, the liver and plasma of LEC rats showed a marked elevation of free copper, especially at the stage of acute hepatitis, in parallel with an increase of total copper levels in the livers and a decrease of plasma caeruloplasmin (ferroxidase I) activity. At the onset of jaundice, the total copper levels, however, decreased in liver, but increased in plasma, while free copper levels in both liver and plasma remained higher. Free iron levels in both liver and plasma were also determined and did not change significantly, except for the case of plasma in jaundiced rats. The data are consistent with a proposal in which increased levels of redox active free copper in the liver of LEC rats catalyze Fenton-type reactions, producing a large flux of hydroxyl radicals that would play an important role in the observed liver dysfunction, leading to acute hepatitis, and finally, hepatocarcinoma. This is the first demonstration that the free copper may participate in the pathophysiology of the LEC rats and Wilson disease.
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PMID:A marked increase in free copper levels in the plasma and liver of LEC rats: an animal model for Wilson disease and liver cancer. 970 24

Ceruloplasmin is excreted mostly in the apo-form in Wilson's disease patients and Long-Evans rats with a cinnamon-like coat color (LEC rats), an animal model for Wilson's disease, and hence the concentration of Cu in the plasma is low. However, it increases toward and at the onset of acute hepatitis in LEC rats, the increased Cu in the plasma being bound to ceruloplasmin, metallothionein and albumin. Changes in the concentration of Cu in red blood cells (RBCs) were monitored with age for the first time together with that in the plasma in LEC rats. Cu in the RBCs was found to increase to a 5-7 times higher level than that in the plasma toward the onset and peaked at the onset, the pattern being similar to that in the plasma. The source of the Cu increase in the RBCs was discussed, and it was assumed that the so-called free Cu ions that leak from the damaged hepatocytes are bound to albumin and/or taken up by the RBCs.
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PMID:Copper increases in both plasma and red blood cells at the onset of acute hepatitis in LEC rats. 1046 85

Tetrathiomolybdate (TTM) can be used as a specific chelator to remove copper (Cu) accumulating in the form bound to metallothionein (MT) in the livers of Wilson disease patients and Long-Evans rats with a cinnamon-like coat color (LEC rats). However, an adverse effect, hepatotoxicity, was observed occasionally on its clinical application. The mechanism underlying the adverse effect of TTM has been studied in comparison with dithiomolybdate (DTM), and a safer and more effective therapy by TTM was proposed based on the mechanism. The activity of glutamic-pyruvic transaminase (GPT) in serum was shown to increase significantly on the treatment of Wistar rats with sulfide produced through hydrolytic degradation of TTM and DTM, the latter being more easily degraded. The hydrolytic degradation of TTM was enhanced under acidic conditions. Cu in Cu-containing enzymes such as Cu,Zn-superoxide dismutase (SOD) in liver and ceruloplasmin (Cp) in plasma was decreased by excessive thiomolybdates, the Cu being found in the plasma in the form of a Cu/thiomolybdate/albumin complex. The decreased amounts of Cu in SOD and Cp were explained by the sequestration of Cu from their chaperones by thiomolybdates rather than the direct removal of Cu from the enzymes. Although both TTM and DTM remove Cu from MT, DTM is not appropriate as a therapeutic agent for Wilson disease due to its easy hydrolysis and production of sulfide.
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PMID:Comparative mechanism and toxicity of tetra- and dithiomolybdates in the removal of copper. 1047 4

In an animal model of Wilson disease, Long-Evans rats with cinnamon-colored coat (LEC rats), copper (Cu) accumulates in the liver with age up to the onset of acute hepatitis owing to a hereditary defective transporter for the efflux of Cu, ATP7B. The plasma Cu concentration is low in LEC rats because of the excretion of apo-ceruloplasmin (apo-Cp). However, toward and after the onset of chronic hepatitis, plasma Cu concentration increases in the form of holo-Cp, while the liver Cu concentration is maintained at a constant level without the occurrence of fulminant hepatitis. In the present study, the material balance of Cu was studied in LEC rats with chronic hepatitis in order to elucidate the mechanisms underlying the increase of holo-Cp in plasma and the maintenance of Cu at a constant level in the liver. The relationship between the Cu concentration and ferroxidase activity of Cp was analyzed in the plasma of LEC rats of different ages and of Wistar rats fed a Cu-deficient diet for different durations. Cu was suggested to be delivered to Cp in an all-or-nothing manner, resulting in the excretion of fully Cu-occupied holo-Cp (Cu(6)-Cp) or totally Cu-unoccupied Cu(0)-Cp (apo-Cp), but not partially Cu-occupied Cu(n)-Cp (where n = 1-5). The increase of holo-Cp in acute and chronic hepatitis in LEC rats was explained by the delivery of Cu, accumulating in the non-metallothionein-bound form, to Cp outside the Golgi apparatus of the liver. The plasma Cu concentration and ferroxidase activity were proposed to be specific indicators of the appearance of non-metallothionein-bound Cu in the liver of LEC rats.
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PMID:Copper balance and ceruloplasmin in chronic hepatitis in a Wilson disease animal model, LEC rats. 1224 7


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