title: Binding characteristics of an androgen receptor in the ovaries of coho salmon, Oncorhynchus kisutch.
abstract: Androgen receptors were identified in the cytosol from ovaries of juvenile coho salmon, Oncorhynchus kisutch. The binding for the synthetic androgen mibolerone was specific and saturable (Kd = 0.32 +/- 0.02 nM; Bmax = 15.31 +/- 4.31 fmol/mg protein). Bound [3H]mibolerone was much higher in ovarian cytosol than in cytosolic extracts from heart, liver, and muscle. [3H]mibolerone specific binding was 50% lower in the plasma than in the ovarian cytosolic extracts. [3H]mibolerone binding was displaced most effectively by those 17 alpha-methylated synthetic androgens (mibolerone, methyltestosterone, methylandrostanolone) that can induce functional masculinization in fish. The naturally occurring androgens 11-ketotestosterone and 5 alpha-dihydrotestosterone both displaced [3H]mibolerone binding, but they were 10- to 100-fold less effective than the 17 alpha-methylated androgens. Testosterone, 11 beta-hydroxyandrostenedione, estradiol, progesterone, and 17 alpha,20 beta-dihydroxyprogesterone were not potent competitors. [3H]mibolerone specific binding was reduced after preincubation with trypsin. About 25% of the binding in the cytosolic extract had DNA binding affinity under experimental conditions. The characteristics of this androgen binding site are consistent with a model of receptor-mediated steroid-induced sex inversion.
authors: Oregon Cooperative Fishery Research Unit, Oregon State University, Corvallis 97331.
authors: M S
authors: MS
authors: Fitzpatrick
authors: W L
authors: WL
authors: Gale
authors: C B
authors: CB
authors: Schreck
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D013196:Dihydrotestosterone / Q000031:analogs & derivatives / Q000378:metabolism; D005260:Female; D008777:Methyltestosterone / Q000378:metabolism; D008982:Molybdenum / Q000494:pharmacology; D009277:Nandrolone / Q000031:analogs & derivatives / Q000378:metabolism; D017684:Oncorhynchus kisutch / Q000378:metabolism*; D009928:Organ Specificity; D010053:Ovary / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D011485:Protein Binding / Q000502:physiology; D011944:Receptors, Androgen / Q000032:analysis / Q000378:metabolism*; D014316:Tritium; D014357:Trypsin / Q000494:pharmacology
chemical_list: D011944:Receptors, Androgen; D013196:Dihydrotestosterone; D014316:Tritium; C044659:molybdate; D009277:Nandrolone; D008982:Molybdenum; C100075:mibolerone; D014357:Trypsin; C008376:mestanolone; D008777:Methyltestosterone