Effect of xenoestrogen exposure on the expression of cytochrome P450 isoforms in rainbow trout liver

• Published in: Environmental toxicology and chemistry Vol. 21; no. 11; pp. 2445 - 2451
• Main Authors: Katchamart, Sirinmas, Miranda, Cristobal L., Henderson, Marilyn C., Pereira, Clifford B., Buhler, Donald R.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Periodicals, Inc 01-11-2002; SETAC
• Subjects: 4-tert-octylphenol; Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Blotting, Northern; Blotting, Western; Cytochrome P-450 CYP4A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System - biosynthesis; Cytochrome P450; Diethylstilbestrol - pharmacology; Down-Regulation; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Effects of pollution and side effects of pesticides on vertebrates; Enzyme-Linked Immunosorbent Assay; Estradiol - pharmacology; estrogenic activity; estrogens; Female; Freshwater; Fundamental and applied biological sciences. Psychology; Genistein - pharmacology; Injections, Intraperitoneal; Isoenzymes; Liver; Male; Methoxychlor - pharmacology; Microsomes, Liver - drug effects; Microsomes, Liver - enzymology; Microsomes, Liver - metabolism; Mixed Function Oxygenases - antagonists & inhibitors; Oncorhynchus mykiss; Oncorhynchus mykiss - metabolism; Phenols - pharmacology; Rainbow trout; Vitellogenin; Vitellogenins - blood; Water Pollutants, Chemical - pharmacology; Xenoestrogen; Salmonidae; Mimetic hormone; Insecticide; Digestive system; Toxicity; Cytochrome P450; Liver; Pesticides; Estrogen; Biological marker; Exposure; Endocrine disruptor; Methoxychlor; Oncorhynchus mykiss; Vitellogenin; Young animal; Aquatic environment; Vertebrata; Organochlorine compounds; Pisces; Diethylstilbestrol; Water pollution; Comparative study
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1002/etc.5620211125

We studied the estrogenic effects of model chemicals in one‐year‐old juvenile rainbow trout. Methoxychlor (20 mg/kg), diethylstilbestrol (15 mg/kg), 4‐tert‐octylphenol (25 and 50 mg/kg), and biochanin A (25 and 50 mg/kg) were injected intraperitoneally on days 1, 4, and 7. Fish were sacrificed on day 9 and examined for multiple biomarkers. All of the test chemicals caused increases in plasma vitellogenin levels, a biomarker of estrogenicity. Treatment with the xenoestrogens decreased hepatic lauric acid hydroxylase activity and, as shown by Western blots, also generally reduced expression of hepatic cytochrome P450s 2K1 (CYP2K1), 2M1 (CYP2M1), and 3A27 (CYP3A27) at the protein level. Both doses of biochanin A also significantly induced P4501A (CYP1A) and greatly increased hepatic 7‐ethoxyresorufin‐O‐deethylase (EROD) activity. These findings suggest that methoxychlor, diethylstilbestrol, 4‐tert‐octylphenol, and biochanin A were all estrogenic and mimicked 17b‐estradiol (E2) in repressing the expression of cytochrome P450 isoforms (CYP2K1, CYP2M1, and CYP3A27) in the rainbow trout liver. Additionally, biochanin A was found to induce CYP1A in this fish species.