[some features of nuclear genome transcription at early stages of liver regeneration. RNA-polymerase activity of isolated nuclei].

The RNA-polymerase activity of isolated nuclei after 1, 3, 6, 12 and 24 hrs following partial hepatectomy was studied. The enzyme activity showed almost a 2-fold decrease after the first post-operative hour, followed by an increase of activity which reached its maximum after 6 hrs. A decrease of nuclear hepatocyte RNA-polymerase sensitivity to alpha-amanitine after 1 and 3 hrs following the surgery was found. After 6 hrs the enzyme was activated by alpha-amanitine. Using selective incorporation of four labelled ribonucleoside triphosphates, it was shown that alpha-amanitine causes a shift in the nucleotide composition of RNA synthesized in the regenerating liver towards the AU-type RNA.