[Early changes in template DNA structure following glucocorticoid injection].

The structure of chromatin is changed at early stages of glucocorticoid hormone interaction with rat hepatocytes. These changes consist in: a) increase of actidine orange binding in rate liver nuclei after injection of the hormone; b) decrease of the number of sites in chromatin which are sensitive to nuclease S1; c) inhibition of the nuclei capacity for DNA synthesis in the presence of E. coli DNA polymerase and d) increase of molecular weight of DNA fragments. The data obtained suggest that at early stages of hormonal induction part of template DNA ruptures is reconstituted, which can result in an increase of DNA molecular weights and changes in chromatin superstructure and the template properties of the protein.