Linked Life Data

8117926

Source:http://linkedlifedata.com/resource/pubmed/id/8117926

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1994-4-4
pubmed:abstractText
The cytochromes P450 (P450) involved in the epoxidation of the rat carcinogen acrylonitrile (ACN) to the mutagen 2-cyanoethylene oxide (CEO) have been investigated in hepatic microsomes from F-344 rats and humans. Induction of P450 2E1 by acetone treatment increased the Vmax for rat microsomal CEO formation 5-fold, while ACN treatment had little effect. Treatment with beta-naphthoflavone, dexamethasone, and phenobarbital had little effect upon Vmax but increased the KM 3- to 5-fold. The P450 ligand 1-phenylimidazole and substrate ethanol were potent inhibitors of ACN epoxidation after all treatments. 2-(Diethylamino)ethyl 2,2-diphenylvalerate (SKF 525A; 0.1 mM) was not an effective inhibitor with microsomes from untreated or acetone-treated rats, but inhibited approximately 50% following dexamethasone or phenobarbital treatment. Antibodies to P450 2E1 inhibited > 85% of the ACN epoxidation activity in microsomes from untreated or beta-naphthoflavone- or acetone-treated rats, but only produced 40% and 60% inhibition following dexamethasone or phenobarbital treatments, respectively. These results indicate that P450 2E1 is the major catalyst of ACN epoxidation in untreated rats and that other forms of P450 can also epoxidize ACN. Diethyldithiocarbamate (0.1 mM) was a potent irreversible inhibitor of ACN epoxidation after all of the induction treatments, indicating that it is not specific for P450 2E1. Chlorzoxazone (2 mM) produced 75-90% inhibition after all of the induction treatments, indicating that it interacts with several rodent P450 isoforms in addition to 2E1. Human hepatic microsomes (n = 6) epoxidized ACN with Vmax'S ranging from 129 to 315 pmol of CEO formed/(min.mg of protein) and KM's from 12 to 18 microM.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0893-228X
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
866-71
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:articleTitle
Epoxidation of acrylonitrile by rat and human cytochromes P450.
pubmed:affiliation
Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't