title: Characterization of a cytosolic estrogen receptor and its up-regulation by 17 beta-estradiol and the xenoestrogen 4-tert-octylphenol in the liver of eelpout (Zoarces viviparus).
abstract: Estrogen binding activity was revealed in the cytosolic fraction of hepatic extracts from adult male and female eelpout (Zoarces viviparus). The binding moiety was characterized by a single class of high affinity binding sites (K(d)=0.59+/-0.05 nM in males and 1.06+/-0.10 nM in females). The affinity was significantly higher in males. Binding sites were satiable and binding capacity was significantly elevated in vitellogenic females (2.92+/-0.28 pmol/g) compared to males (1.67+/-0.11 pmol/g). The binding was specific to known estrogens but not to other tested steroids. The binding moiety was able to bind to DNA-cellulose and was extractable by high salt concentrations. A time-course study of estrogen binding activity in liver cytosol and of vitellogenin (Vtg) in plasma, after intraperitoneal (i.p.) injections of 17 beta-estradiol (E(2)) in male eelpout, was carried out. It was shown that both are inducible by E(2). Estrogen binding activity was significantly elevated 48 h and Vtg 72 h after E(2) treatment. The binding moiety was hereafter designated as a cytosolic estrogen receptor (ER). The estrogenicity of 4-tert-octylphenol (OP) was evaluated by measuring ER and Vtg after i.p. treatment. OP-treatment increased both receptor levels and Vtg concentrations in male fish, indicating that OP acts as an estrogen in male eelpout.
authors.affiliation: Institute of Biology, University of Southern Denmark, Odense University, Campusvej 55, DK-5230 Odense, Denmark.
authors.forename: T K
authors.initials: TK
authors.lastname: Andreassen
authors.forename: B
authors.initials: B
authors.lastname: Korsgaard
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002482:Cellulose / Q000031:analogs & derivatives* / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism* / Q000494:pharmacology; D004967:Estrogens / Q000032:analysis / Q000378:metabolism; D005260:Female; D005399:Fishes / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D010636:Phenols / Q000633:toxicity*; D011485:Protein Binding; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism*; D012044:Regression Analysis; D012621:Seasons; D013501:Surface-Active Agents / Q000633:toxicity; D015854:Up-Regulation; D014819:Vitellogenins / Q000097:blood / Q000187:drug effects
chemical_list: C033190:DNA-cellulose; D004967:Estrogens; D010636:Phenols; D011960:Receptors, Estrogen; D013501:Surface-Active Agents; D014819:Vitellogenins; D004958:Estradiol; D002482:Cellulose; D004247:DNA; C105260:4-tert-octylphenol