Glucocorticoid-mediated potentiation of P450 induction in primary culture of rainbow trout hepatocytes.
Induction of 7-ethoxyresorufin O-deethylase activity (a cytochrome P450IA-dependent activity) by beta-naphthoflavone (0.36 microM) is increased 2-3-fold by dexamethasone or cortisol (10(-9)-10(-7) M) in rainbow trout hepatocyte cultures. This potentiation does not seem to be a time-dependent process and could be a classical glucocorticoid receptor-mediated event resulting in enhanced transcriptional activation of the CYP1A, as previously shown in mammals. Since glucocorticoid levels can increase in fish exposed to pollutants, such steroids may interfere with the induction response to xenobiotics.
Laboratoire d'Ecotoxicologie INRA-ENVL, Ecole Nationale Vétérinaire de Lyon, France.
A
A
Devaux
M
M
Pesonen
G
G
Monod
T
T
Andersson
D000818:Animals; D001571:Benzoflavones / Q000494:pharmacology; D002478:Cells, Cultured / Q000187:drug effects; D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D003907:Dexamethasone / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D005399:Fishes / Q000378:metabolism; D005938:Glucocorticoids / Q000097:blood / Q000494:pharmacology*; D006854:Hydrocortisone / Q000494:pharmacology; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D010088:Oxidoreductases / Q000096:biosynthesis; D014444:Tyrosine Transaminase / Q000096:biosynthesis; D019324:beta-Naphthoflavone
D001571:Benzoflavones; D005938:Glucocorticoids; D019324:beta-Naphthoflavone; D003907:Dexamethasone; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1; D014444:Tyrosine Transaminase; D006854:Hydrocortisone