|Binding characteristics of an androgen receptor in the ovaries of coho salmon, Oncorhynchus kisutch|
Fitzpatrick, M.S.; Gale, W.L.; Schreck, C.B. (1994). Binding characteristics of an androgen receptor in the ovaries of coho salmon, Oncorhynchus kisutch. Gen. Comp. Endocrinol. 95: 399-408
In: General and Comparative Endocrinology. Elsevier: New York,. ISSN 0016-6480; e-ISSN 1095-6840
Androgenesis; Biochemische analyse; Eierstokken; Endocrinologie; Fish physiology; Juvenielen; Sex determination; Sex reversal; Oncorhynchus kisutch (Walbaum, 1792) [WoRMS]; Marien
|Auteurs|| || Top |
- Fitzpatrick, M.S.
- Gale, W.L.
- Schreck, C.B.
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 plus or minus 0.02 nM; Bmax = 15.31 plus or minus 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.