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Cytochrome P450 monooxygenase gene expression and protein activity in cultures of adult cardiomyocytes of the rat

: Thum, T.; Borlak, J.


British journal of pharmacology 130 (2000), Nr.8, S.1745-1752
ISSN: 0007-1188
ISSN: 1476-5381
Fraunhofer ITA ( ITEM) ()
CYP monooxygenase; EROD; Cytochrome P-450; gene expression; Messenger RNA; testosterone; heart cells

There are a substantial number of drugs acting either directly or indirectly on the heart, but surprisingly, little is known about the metabolic capacity of heart muscle cells. We therefore investigated the gene expression and protein activity of cytochrome P450 isozymes in cultures of adult cardiomyocytes of the rat. Semi-quantitative CYP gene expression pattern suggests CYP1A1 and CYP2B1/2 to be key players in cardiomyocytes and upon treatment with Aroclor 1254 approximate 4 fold inductions could be observed for both gene families, when compared with appropriate controls. The mRNA expression of most genes was sustained for prolonged periods of time, e.g. up to 120 h in culture and in the case of the CYP3A1 gene an approximate 10 fold induction was observed at the higher Aroclor 1254 dose level (10 µM) in 24 h old cultures. The constitutively expressed genes, e.g. CYP2C11 and CYP2E1 are expressed throughout the entire culture period (5 days) and did not respond to Aroclor 1254 treatment. CYP4A1 was mainly expressed in freshly isolated cardiomyocytes of control animals and its expression declined rapidly in culture. There was good agreement between gene expression and translated protein activity using 7-ethoxyresorufin and testosterone as substrates. The data reported herein should foster the routine use of freshly isolated and cultivated cardiomyocytes for drug profiling and toxicity studies.