Association of triiodothyronine binding activity to soluble adenylate cyclase in testicular preparations

Cytosolic adenylate cyclase activity from rat seminiferous tubules was purified by chromtography in DEAE-cellulose, hydroxylapatite and Bio-Gel A-0.5 m as well as by centrifugation in sucrose gradients. In all these purification steps, fractions with adenylate cyclase activity also contained binding activity for L-T3. Binding studies indicate the existence of two L-T3 receptor components associated to adenylate cyclase activity. The component exhibiting the highest hormone affinity has the lowest binding capacity.