Cytosol androgen binding in submandibular gland and kidney of the normal mouse and the mouse with testicular feminization

Androgen binding was investigated in the cytosol of the submandibular gland and the kidney from normal mice, mice with testicular feminization (Tfm), and carriers of the Tfm gene. In both tissues from normal mice an androgenbinding complex was observed from birth throughout life that could not be detected in Tfm animals at any age. This complex was precipitated at 35 and 40% saturation with ammonium sulfate in the kidney and the submandibular gland, respectively, and had an approximate sedimentation coefficient of 8S in the submandibular gland and 10S in the kidney. In both tissues of the normal female, the apparent dissociation constants (Kd) for testosterone and dihydrotestosterone were about 1 nM, and the binding capacity averaged 20 fmol · mg protein⁻¹. The number of binding sites in preparations from Tfm carriers was intermediate between that in the Tfm and the normal female. In 0.5M KC1 the 8S receptor of normal submandibular gland sediments at about 3S, and the 10S receptor of normal kidney sediments at about 4.5S. In the submandibular gland, binding of approximate 3S size was also observed. The latter was present in Tfm animals as well as in normal mice, it precipitated at 70% saturation with ammonium sulfate, and it was detectable from birth. In the kidney the only low molecular weight binding for androgen was about 4.5S in size.