Androgen receptor in the thumb pad of Rana esculenta: dynamic aspects

The androgen receptor (dissociation constant, 6 x 10(-9) mol/l) present in the 105 000 g cytosol fraction of the thumb pad of Rana esculenta is hormone dependent. The number of testosterone binding sites decreased in the absence of the testes and in long-term castrated animals (75 days) became undetectable. Administration of testosterone (50 ng) induced the replenishment of the cytophasmic androgen receptor; its concentration also varied during the annual reproductive cycle.