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: Overexpression of a cytochrome P-450 of the 2a family (Cyp2a-5) in chemically induced hepatomas from female mice.
    Author: Jounaïdi Y, Bonfils C, Périn F, Negishi M, Lange R.
    Journal: Eur J Biochem; 1994 Feb 01; 219(3):791-8. PubMed ID: 8112330.
    Abstract:
    Chemical hepatocarcinogenesis in female mice, induced by 5,9-dimethyl(7H)dibenzo[c,g]carbazole, leads to the overexpression of a cytochrome P-450 of the 2a family. This protein was identified as Cyp2a-5, by the use of immunoblots obtained from isoelectric focusing gels. This method allowed the distinction of Cyp2a-5 from Cyp2a-4, another mouse liver cytochrome P-450, by taking advantage of their slightly different pI values. The theoretical pI values, determined from the amino acid sequence, were pI 9.91 for Cyp2a-4 and pI 10.01 for Cyp2a-5. Other structurally related forms were not detected. In hepatomas from female mice, only the Cyp2a-5 form was overexpressed (2-3 fold). Male mice showed a weak expression of Cyp2a-4 and Cyp2a-5 in control liver samples and in hepatomas. The expression of both forms was increased more than fivefold upon castration. Pyrazole induces specifically the Cyp2a-5 form. The Cyp2a-5 overexpression was correlated with enhanced microsomal coumarin-7-hydroxylase and testosterone-15 alpha-hydroxylase activities. An immunohistochemical study showed that Cyp2a-4 and Cyp2a-5 are expressed uniformly in female livers, but centrilobularly in male livers. In hepatomas, this localisation is perturbed; in females we observed a focal cell localisation, and the Cyp2a-containing cells were often hypertrophic and polyploid. In hepatomas from male mice, the Cyp2a-containing cells became dispersed. From a comparison with other studies, the Cyp2a-5 overexpression appears to be a general feature of hepatocarcinogenesis in mice.
    [Abstract] [Full Text] [Related] [New Search]