Effects of alpha-amanitine on chromatin in regenerating rat hepatocytes: a biochemical and morphologic study.

Almost all the chromatin in nuclei of regenerating rat liver hepatocytes 15 h and particularly 24 h after partial hepatectomy appeared as decondensed chromatin. Treatment with alpha-amanitine induced a clear condensation of decondensed chromatin as early as 30 min after toxin injection. The degree of condensation increased further until, 2 h after poisoning, almost all the chromatin was found to be in condensed form. Because the synthesis of DNA, after toxin injection, was not modified during the first 2h and 30 min, our results indicate that the chromatin condensation did not affect the synthesis of DNA. In the present paper the relationships between the inhibition of RNA synthesis and the chromatin ultrastructural changes are also discussed.