Androgen and estrogen binding in rat skeletal and perineal muscles.
Specific in vitro binding of [3H]testosterone (T), 5ALPHA[3H]dihydrotestosterone (DHT), and [3H[estradiol (E2) was demonstrated in the 30 000 X g supernatant (cytosol) of thigh muscles (TM) and of the levator ani - bulbocavernosus muscle complex (LA-BC) by gel filtration through Sephadex G-25 columns. In TM cytosol, T and E2 [are bound with high affinity  (Ka = 1.1 X 10(9) M-1, and 2.3 X 10(9) M-1 respectively) whereas DHT binding is of lower affinity (Ka = 5.0 X 10(7) M-1).] In LA-BC cytosol, T, E2, and DHT are bound with high affinity (Ka = 1.9 X 10(9) M-1, 0.3 X 10(9) M-1, and 0.5 X 10(9) M-1, respectively). Competition experiments suggest that the binding of the three hormones (T, E2, and DHT) is due to different proteins. In addition to TM and LA-BC, T and E2 binding was found in other muscles of male and female rats, including gastrocnemius, the pectoralis, diaphragm, and heart.
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D013196:Dihydrotestosterone / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism*; D006854:Hydrocortisone / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D011956:Receptors, Cell Surface; D013739:Testosterone / Q000378:metabolism*
D009124:Muscle Proteins; D011956:Receptors, Cell Surface; D013196:Dihydrotestosterone; D013739:Testosterone; D004958:Estradiol; D006854:Hydrocortisone