These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.
Pubmed for Handhelds
PUBMED FOR HANDHELDS
Search MEDLINE/PubMed
Title: Regulation of constitutive rat hepatic cytochromes P450 by 3-methylcholanthrene. Author: Jones EJ, Riddick DS. Journal: Xenobiotica; 1996 Oct; 26(10):995-1012. PubMed ID: 8905915. Abstract: 1. Induction of cytochrome P450 (CYP) enzymes of the CYP1A subfamily by aromatic hydrocarbons such as 3-methylcholanthrene (MC) is accompanied by down-regulation of other CYPs that are expressed constitutively in rat liver. 2. We examined the time-course of the effects of MC on the expression of CYP2C11 and 3A2 in the liver of male rats at the catalytic activity, apoprotein and mRNA levels. 3. A single intraperitoneal dose of MC (50 mg/kg) caused an increase in total hepatic microsomal CYP and haem content, and a marked induction of CYP1A1 catalytic activity (7-ethoxyresorufin O-deethylase) and apoprotein. The activity of NADPH-cytochrome P450 reductase was not altered. 4. MC treatment decreased CYP2C11 and 3A catalytic activity (testosterone 16 alpha- and 6 beta-hydroxylase respectively) and apoprotein, and there was a trend for suppression of 2C11 and 3A2 mRNA. Following this initial down-regulation, CYP2C11 catalytic activity and 3A catalytic activity and apoprotein were elevated above control levels. Although CYP2C11 and 3A2 mRNA levels showed a similar trend, these effects did not achieve statistical significance. 5. CYP2C11 and 3A2 appear to be regulated by MC at a pre-translational level. CYP2C11 suppression will serve as a valuable model for study on the mechanisms by which aromatic hydrocarbons act to negatively influence gene expression.[Abstract] [Full Text] [Related] [New Search]