On the mechanism of hormone action: VI. Increase in template activity of ribonucleic acid from isolated nuclei incubated in the presence of hormone

Abstract

1. Isolated nuclei of the target organs were incubated in vitro with ecdysone and cortisol, respectively, and the effects on the template activity of nuclear RNA were measured in a ribosomal amino acid-incorporating system. 2. Ecdysone caused an increase in template activity in RNA from larval epidermis nuclei of Calliphora erythrocephala Meig. 3. Incubation of rat liver nuclei in the presence of cortisol also led to the same effect on template activity of the RNA. 4. Cortisone increased the template activity of liver nuclear RNA to a lesser extent. Pregnanediol had no effect. 5. These effects of the hormones on isolated nuclei constitute further proof for a mechanism in which, as a first step, hormones interact with nuclear constituents causing the transcription of genetic information into template RNA.