Androgen receptors in the prostate of the Rhesus monkey.

The presence of an androgen receptor protein in the supernatant preparation of the prostate from Rhesus monkey (macaca mulatta) is described. The molecular weight of this receptor protein was found to be 2.8–2.9×105 daltons. The levels of free and bound androgen receptors were measured in the caudal and cranial lobes of the prostate by an exchange assay using methyltrienolone (R1881). The concentration of the free binding sites in the caudal lobe ranged between 3.7–23.7 fmol/mg protein. The value in the cranial lobe was 2.0–7.7 fmol/mg protein. The total binding sites in the caudal lobe ranged between 36.0–112.7 and in the cranial between 21.2–55.0 fmol/mg. The bound receptor ranged between 43.3–109.0 and 19.1–47.3 fmol/mg protein for caudal and cranial lobes respectively. The level of both bound and free receptors was found to be significantly higher in the caudal lobe. This data suggests that the two lobes of the prostate in the Rhesus monkey can be equated with the two zones of the human prostate in respect of androgen responsiveness.