Androgen binding activity in the spongy tissue of mammalian penis

The binding of [3H]R1881 to cytosol fractions was determined for the spongy tissues of horse, porcine and human penis. Binding of [3H]R1881 to cytosol fractions from these spongy tissues was found to be specific with high affinities (mean of Kd; 1.8 X 10(-10) M) but with equally low binding capacities (mean of 4.66 fmol/mg. protein). Saturation analysis revealed that the binding capacity was similar for both corpus cavernosum and corpus spongiosum of horse penis. We conclude that a trace amount of androgen receptor is present in spongy tissue of the penis and that there is no difference in cytosolic receptors between corpus cavernosum and corpus spongiosum in adult mammalian penis.