title: Estrogenic effects in flounder Platichthys flesus orally exposed to 4-tert-octylphenol.
abstract: The estrogenic effect of dietary 4-tert-octylphenol in the flounder Platichthys flesus was investigated in the laboratory. In the first experiment male flounders were fed doses of 10, 50 and 100 mg 4-tert-octylphenol kg(-1) BW or 0.05 mg 17beta-estradiol kg(-1) BW every second day for 10 days. Increases in the plasma content of vitellogenin were observed on day 6 by the first sampling in all treated groups. An effect of octylphenol on the size of the liver and testis was only seen in one of the exposed group (50 mg 4-tert-octylphenol kg(-1) BW). An increase in the concentration of 4-tert-octylphenol was found in both liver and muscle tissues of all 4-tert-octylphenol treated fish. The concentration of 4-tert-octylphenol (ng g(-1) WW) in liver tissue was four to five times greater than the concentration in muscle tissue. Only about 8% of the 4-tert-octylphenol administered to the group receiving 50 mg 4-tert-octylphenol kg(-1) BW was retained in the liver and the muscles at the end of the experiment. In the second experiment male flounders were exposed to a low dose range of 4-tert-octylphenol (1 to 25 mg 4-tert-octylphenol kg(-1) BW) in order to establish the dose-response relationship of 4-tert-octylphenol when applied by feeding to flounder. Vitellogenin induction (LOED) occurred at 10 and 5 mg 4-tert-octylphenol kg(-1) BW after, respectively, 6 and 11 days of exposure. Based on a logistic regression analysis the effect dose (ED(50)) could be determined as 8.2 and 5.6 mg 4-tert-octylphenol kg(-1) BW on day 6 and 11, respectively. 4-tert-octylphenol accumulated in liver, muscle and testis tissue, and a significant accumulation in liver was found at 2.5 mg 4-tert-octylphenol kg(-1) BW and in muscle and testis at 5 mg 4-tert-octylphenol kg(-1) BW. Finally, a positive correlation between the plasma vitellogenin concentration and the liver tissue concentration of 4-tert-octylphenol was established as well as a positive correlation between the content of 4-tert-octylphenol in liver and muscle/testis tissue.
authors.affiliation: Institute of Biology, University of Southern Denmark, Odense, Campusvej 55, DK-5230 M Odense, Denmark. louisem@biology.sdu.dk
authors.forename: Louise L
authors.initials: LL
authors.lastname: Madsen
authors.forename: Bodil
authors.initials: B
authors.lastname: Korsgaard
authors.forename: Poul
authors.initials: P
authors.lastname: Bjerregaard
mesh_terms: D000818:Animals; D004032:Diet; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000378:metabolism; D004968:Estrogens, Non-Steroidal / Q000493:pharmacokinetics / Q000633:toxicity*; D005432:Flounder / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000473:pathology; D016015:Logistic Models; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D010636:Phenols / Q000493:pharmacokinetics / Q000633:toxicity*; D013501:Surface-Active Agents / Q000493:pharmacokinetics / Q000633:toxicity*; D013737:Testis / Q000187:drug effects / Q000473:pathology; D014819:Vitellogenins / Q000097:blood*
chemical_list: D004968:Estrogens, Non-Steroidal; D010636:Phenols; D013501:Surface-Active Agents; D014819:Vitellogenins; D004958:Estradiol; C105260:4-tert-octylphenol