title: Up-regulation of estrogen receptor mRNA and estrogen receptor activity by estradiol in liver of rainbow trout and other teleostean fish.
abstract: Injection of estradiol (E2) into immature rainbow trout resulted in the induction of the hepatic vitellogenin gene mediated by the nuclear estrogen receptor (ER). Liver ER mRNA rose markedly on E2 treatment in three groups of trout kept at different temperatures. Only in the group kept at 4 degrees C did the total cellular ER, as measured by [3H]estradiol-binding activity in nuclear and cytosol fractions, parallel the ER mRNA level. In fish kept at 9 degrees C and 15 degrees C, the ratio of total ER activity to ER mRNA fell during chronic E2 treatment, probably reflecting translational of post-translational control mechanisms. Upregulation of ER mRNA also occurred in sea raven, sculpin, winter flounder, and Atlantic salmon after E2 treatment. Intrahepatic ER activity rose proportionately in Atlantic salmon kept at 6-9 degrees C but not in sea raven, sculpin, or flounder. We conclude that the regulation of ER expression in teleosts is complex and includes transcriptional, translational, and post-translational elements and is influenced by environmental temperature.
authors.affiliation: Department of Biochemistry, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: M E
authors.initials: ME
authors.lastname: MacKay
authors.forename: J
authors.initials: J
authors.lastname: Raelson
authors.forename: C B
authors.initials: CB
authors.lastname: Lazier
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D015152:Blotting, Northern; D004958:Estradiol / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D005399:Fishes / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D014158:Transcription, Genetic; D015854:Up-Regulation; D014819:Vitellogenins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D011960:Receptors, Estrogen; D014819:Vitellogenins; D004958:Estradiol