[Interaction of hormone-receptor complexes from normal and tumorous tissues with DNA and their effect on the RNA polymerase activity of isolated nuclei].

A study was made of the interaction of the thyroxine hormone-receptor complexes (HRC) from hepatocytes and sarcoma M1 cells with DNA and the involvement of these complexes in the regulation of the RNA-polymerase activity of isolated hepatic cell nuclei. Unlike sarcoma HRC, rat liver HRC showed a weak interaction with DNA. Against a background of considerable stimulation of the incorporation of precursors in RNA under the influence of rat liver HRC (2.64 times), sarcoma HRC increased RNA synthesis in the system by 31.7% only to determine the RNA-polymerase activity of the nuclei. Proceeding from these results the authors have concluded that a thyroxine-binding receptor protein in malignant tissues is devoid of biological activity in the regulation of gene expression by the thyroid hormones, at least in the transcription phase.