The hamster ductus deferens cloned tumor cell line (DDT1) has been shown to contain both androgen and glucocorticoid binding activity. The androgen receptor binding site concentration is 1.07 × 10−13 mol of testosterone/mg protein, and testosterone (T) binds with a Kd of 4.3× 10−10M. Dihydrotestosterone (DHT) is also bound to the receptor with a Kd of 2.99 × 10−10M and the binding site concentration is 1.33 × 10−13 mol/mg protein. The order of steroid binding affinity is DHT > T > Estradiol > Progesterone. Cortisol, dexamethasone, and triamcinolone acetonide do not inhibit the androgen binding in vivo or in vitro. In a cell free system antiandrogens inhibit the binding of DHT. The DDT1 cells have a separate receptor for cortisol which binds at saturation 3.44 × 10−13 mol cortisol/mg protein and has a Kd of 4.54 × 10−9M. These studies provide evidence that these endocrine target cells contain specific high affinity receptors for more than one type of steroid. The glucocorticoid receptor may be important for maintaining essential undifferentiated functions while the DHT receptor gives thespecific characteristics of sex hormone responsive tissues.
ASJC Scopus subject areas