Identification of an androgen receptor in the adult chicken oviduct

The chicken oviduct androgen receptor was characterized by sucrose density gradient centrifugation, Scatchard analysis, competition studies, and affinity labeled with dihydrotestosterone 17 beta-bromoacetate. A specific 8.5 S peak was seen on 0.01 M KCl sucrose density gradients when the receptor was labeled with [3H]5 alpha-dihydrotestosterone. Specific 4.6 S peaks were seen when receptor labeled with [3H]5 alpha-dihydrotestosterone or [3H]dihydrotestosterone 17 beta-bromoacetate was analyzed on 0.3 M KCl sucrose density gradients. Scatchard analysis of [3H]5 alpha-dihydrotestosterone binding by oviduct cytosol was consistent with two binding sites. A Kd of 0.13 nM was found for the high affinity androgen receptor. Competition studies showed the following order of ligand affinity: 5 alpha-dihydrotestosterone greater than dihydrotestosterone 17 beta-bromoacetate greater than progesterone greater than estradiol. A 61.2 kDa protein was specifically covalently labeled with [3H]dihydrotestosterone 17 beta-bromoacetate. The chicken oviduct androgen receptor possesses characteristics similar to other androgen receptors, and provides a good source of androgen receptor for physicochemical studies of the native receptor protein.