The androgen receptor in normal human foreskin. I. Stabilization and identification of two receptor subunits

Use of glycerol and the protease inhibitor phenylmethylsulfonyl fluoride resulted in a fourfold increase in the yield of androgen receptor from human neonatal foreskin and a tenfold increase in stability of this receptor. The general physical properties of the androgen-binding component isolated from the cytosol of human neonatal foreskin were found to be consistent with those previously reported for androgen receptors. The synthetic androgen methyltrienolone (R1881) was bound with high affinity (a mean dissociation constant of 0.51 nmol/L) and low capacity (5.6 fmol/mg of protein); maximum binding required 4 hours. Affinity of the receptor was highest for R1881 followed by dihydrotestosterone, testosterone, and progesterone. 17β-Estradiol showed little or no competition. The receptor exhibited a change of sedimentation coefficient from 8S to 4S upon treatment with 0.1 mol/L potassium chloride. Isoelectric focusing demonstrated the existence of two molecular species with apparent isoelectric points of 7.2 and 5.7.