Rainbow trout androgen receptor-alpha fails to distinguish between any of the natural androgens tested in transactivation assay, not just 11-ketotestosterone and testosterone.
We have recently isolated two androgen receptor cDNA clones from the rainbow trout testis. To investigate the functions of the rainbow trout androgen receptor-alpha (rtAR-alpha), we investigated the ligand binding ability and transcriptional activity of rtAR-alpha. Interestingly, in ligand-competition experiments, testosterone (T) (IC(50) 3 x 10(-9) M) competed with [(3)H]mibolerone binding for rtAR-alpha slightly more potently than the teleost fish-specific natural androgen 11-ketotestosterone (11KT) (IC(50) 8 x 10(-9) M), which is thought to be the functional spermatogenesis inducer. In contrast, T (EC(50) 5 x 10(-9) M) and 11KT (EC(50) 6 x 10(-9) M) showed similar efficiency upon cotransfection into EPC cells with a rtAR-alpha expression vector and an androgen-responsive element-based reporter gene. These results indicated that activation of rtAR-alpha does not distinguish between 11KT and T and suggested that a specific system, which is mediated only by 11KT, may exist in the rainbow trout.
Takeo
J
J
Central Research Laboratory, Nippon Suisan Kaisha Ltd., 559-6 Kitanomachi, Hachioji, Tokyo, 192-0906, Japan.
Yamashita
S
S
D000728:Androgens / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D015151:Immunoblotting; D007700:Kinetics; D008024:Ligands; D008297:Male; D009277:Nandrolone / Q000031:analogs & derivatives / Q000378:metabolism; D056918:Nuclear Receptor Coactivators; D015513:Oncogene Proteins; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D011944:Receptors, Androgen / Q000378:metabolism*; D013091:Spermatogenesis / Q000187:drug effects; D013737:Testis / Q000166:cytology / Q000378:metabolism; D013739:Testosterone / Q000031:analogs & derivatives* / Q000378:metabolism*; D045165:Testosterone Congeners / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors; D015533:Transcriptional Activation / Q000502:physiology
D000728:Androgens; D008024:Ligands; C111382:NCOA4 protein, human; D056918:Nuclear Receptor Coactivators; D015513:Oncogene Proteins; D011944:Receptors, Androgen; D045165:Testosterone Congeners; D015534:Trans-Activators; D014157:Transcription Factors; D013739:Testosterone; D009277:Nandrolone; C100075:mibolerone; C003600:11-ketotestosterone