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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1990-5-2
|
| pubmed:abstractText |
We have studied the effects of the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) on cytochrome P-450-dependent monooxygenase activities in several differentiated and dedifferentiated Reuber rat hepatoma cell lines using aryl hydrocarbon (benzo[a]pyrene) hydroxylase (AHH), ethoxyresorufin O-deethylase (EROD), and aldrin epoxidase (AE) as test systems. The following results were obtained: (1) Exposure of cultures to 400 nM TPA for 18-24 h increased AHH activities in the differentiated lines 2sFou, H41IEC3/G- and Fao as well as in the dedifferentiated line 5L, 1.5-2.5-fold. The phorbol ester did not affect AHH activity in the dedifferentiated line H5. (2) EROD, a marker for P-450I, was induced by the phorbol ester to a similar degree as AHH. (3) A monoclonal antibody directed against P-450I strongly inhibited the AHH activity induced by TPA. (4) The onset of AHH or EROD induction by TPA was much later than that elicited by benz[a]anthracene. (6) In contrast to the induction of AHH and EROD, TPA decreased AE activity, a marker for P-450II, by about 50% in all the cell lines containing this monooxygenase activity. (7) The half-maximum-effect concentration of TPA for inducing or suppressing AHH and AE, respectively, was approximately 20 nM. (8) TPA did not interfere with AHH induction by benz[a]anthracene. However, the phorbol ester moderately decreased AHH induction and markedly suppressed AE induction by dexamethasone. The results indicate that TPA simultaneously induces P-450I and suppresses P-450II forms in rat hepatoma cells. P-450I induction by TPA in these cells did not appear to depend on their status of differentiation. Furthermore, the results suggest that the mechanism of P-450I induction by TPA differs from that elicited by polycyclic aromatic hydrocarbons or glucocorticoids.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Antibodies, Monoclonal,
http://linkedlifedata.com/resource/pubmed/chemical/Benz(a)Anthracenes,
http://linkedlifedata.com/resource/pubmed/chemical/Benzopyrene Hydroxylase,
http://linkedlifedata.com/resource/pubmed/chemical/Cytochrome P-450 CYP1A1,
http://linkedlifedata.com/resource/pubmed/chemical/Cytochrome P-450 Enzyme System,
http://linkedlifedata.com/resource/pubmed/chemical/Dexamethasone,
http://linkedlifedata.com/resource/pubmed/chemical/Mixed Function Oxygenases,
http://linkedlifedata.com/resource/pubmed/chemical/Oxidoreductases,
http://linkedlifedata.com/resource/pubmed/chemical/Oxygenases,
http://linkedlifedata.com/resource/pubmed/chemical/Tetradecanoylphorbol Acetate,
http://linkedlifedata.com/resource/pubmed/chemical/aldrin epoxidase,
http://linkedlifedata.com/resource/pubmed/chemical/benz(a)anthracene
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
0300-483X
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
17
|
| pubmed:volume |
61
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
147-59
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:2321243-Animals,
pubmed-meshheading:2321243-Antibodies, Monoclonal,
pubmed-meshheading:2321243-Benz(a)Anthracenes,
pubmed-meshheading:2321243-Benzopyrene Hydroxylase,
pubmed-meshheading:2321243-Cell Differentiation,
pubmed-meshheading:2321243-Cytochrome P-450 CYP1A1,
pubmed-meshheading:2321243-Cytochrome P-450 Enzyme System,
pubmed-meshheading:2321243-Dexamethasone,
pubmed-meshheading:2321243-Drug Interactions,
pubmed-meshheading:2321243-Enzyme Induction,
pubmed-meshheading:2321243-Liver Neoplasms, Experimental,
pubmed-meshheading:2321243-Mixed Function Oxygenases,
pubmed-meshheading:2321243-Oxidoreductases,
pubmed-meshheading:2321243-Oxygenases,
pubmed-meshheading:2321243-Rats,
pubmed-meshheading:2321243-Tetradecanoylphorbol Acetate,
pubmed-meshheading:2321243-Tumor Cells, Cultured
|
| pubmed:year |
1990
|
| pubmed:articleTitle |
Differential effects of 12-O-tetradecanoylphorbol 13-acetate on cytochrome P-450-dependent monooxygenase activities in rat hepatoma cells: induction of P-450I and suppression of P-450II.
|
| pubmed:affiliation |
GSF-Institute of Toxicology, Gesellschaft für Strahlen- und Umweltforschung, Neuherberg, F.R.G.
|
| pubmed:publicationType |
Journal Article,
Comparative Study
|