| Azo dye-induced alterations in vitamin B-6 metabolism and in pyridoxal 5'-phosphate-binding proteins in rat liver. | |
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MedLine Citation:
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PMID: 3007703 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The effects of the hepatocarcinogen, 3'-methyl-4-dimethylamino-azobenzene, on vitamin B-6 metabolism in rat liver were studied. The following parameters were measured: pyridoxal 5'-phosphate (PLP) concentrations in plasma, brain, liver and azo dye-induced hepatomas, as well as the activities of pyridoxine (PN) kinase, pyridoxine 5'-phosphate (PNP) oxidase, PNP phosphatase and PLP-dependent ornithine decarboxylase. Hepatomas more closely resembled fetal than normal adult rat liver with respect to their ability to convert vitamer forms such as PN to coenzymatically active PLP. Microtiter plate enzyme-linked immunosorbent analyses revealed that the absence of PNP oxidase activity in a dissectable hepatoma was attributable to the absence of enzyme protein. In addition, monoclonal antibodies to vitamin B-6 were used in a Western immunoblot technique to examine the effects of azo dye ingestion on the pattern of PLP-binding proteins in cytosolic extracts of liver and hepatomas. Nitrocellulose blots of electrophoretically resolved cytosolic extracts probed for PLP-binding proteins showed increasing complexity with development; hepatomas bore a striking resemblance to fetal liver. The data indicate that hepatomas lose the properties of terminally differentiated hepatic tissue and take on the properties of fetal hepatic tissue characterized by lower concentrations of PLP, selective use of the coenzyme, and a lowered-to-absent capability to convert precursor vitamer forms to PLP. Therefore, with respect to vitamin B-6 metabolism and use, it appears likely that azo dye-induced hepatocarcinogenesis involves proliferation of a stem cell type(s) having the phenotypic characteristics of fetal hepatic tissue. |
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Authors:
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J M Kittler; N T Meisler; J W Thanassi |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The Journal of nutrition Volume: 116 ISSN: 0022-3166 ISO Abbreviation: J. Nutr. Publication Date: 1986 Apr |
Date Detail:
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Created Date: 1986-05-22 Completed Date: 1986-05-22 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0404243 Medline TA: J Nutr Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 588-98 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cytosol / enzymology Densitometry Enzyme-Linked Immunosorbent Assay Liver / drug effects, enzymology, metabolism* Liver Neoplasms, Experimental / chemically induced, metabolism Male Methyldimethylaminoazobenzene / pharmacology* Ornithine Decarboxylase / metabolism Pyridoxal Kinase / metabolism Pyridoxal Phosphate / blood, metabolism Pyridoxaminephosphate Oxidase / metabolism Pyridoxine / blood* Rats Receptors, Cell Surface / drug effects* p-Dimethylaminoazobenzene / analogs & derivatives* |
| Grant Support | |
ID/Acronym/Agency:
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35878//PHS HHS |
| Chemical | |
Reg. No./Substance:
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0/Receptors, Cell Surface; 0/pyridoxal phosphate receptor; 54-47-7/Pyridoxal Phosphate; 55-80-1/Methyldimethylaminoazobenzene; 60-11-7/p-Dimethylaminoazobenzene; 65-23-6/Pyridoxine; EC 1.4.3.5/Pyridoxaminephosphate Oxidase; EC 2.7.1.35/Pyridoxal Kinase; EC 4.1.1.17/Ornithine Decarboxylase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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