In vitro transformation of androgen receptor from murine skeletal muscle by cAMP

Sedimentation constants and DNA-cellulose-binding of cytosolic androgen receptor from murine skeletal muscle were determined in presence of cyclic nucleotides. Without cAMP, two testosterone-binding fractions of similar amount at 4–5S and 8–9S were obtained. With 3μM cAMP the receptor sedimented predominantely at 4–5S. Binding of testosterone-receptor-complexes to DNA-cellulose was enhanced by increasing cAMP-concentrations and reached a maximum at 20–90nM cAMP depending on the DNA-concentration in the test. A similar DNA-binding characteristic was obtained after partial purification of the receptor by affinity chromatography. cGMP had no effect. We conclude that the androgen receptor is transformed in vitro by cAMP.