Actinomycin D and Hydrocortisone: intracellular binding in rat liver.

DNA was found to be the major intracellular binding site for labeled actinomycin D administered in vivo. In analogous studies, hydrocortisone did not bind to nuclear structures. Furthermore, following the administration of actinomycin D, a highly positive correlation was found between the RNA content of the nucleus and the ability of the nucleus to synthesize RNA.