Thioacetamide, adminlstered in a dose of 50/mg/kg for 9 days, produced a profound effect on the distribution and labeling of ribonucleic acid (RNA) of the rat liver. The amount of p-RNA (released by phenol into the aqueous phase) and r-RNA (which re mained in the phenol), was increased twoto threefold in the nuclei. In the nucleoli, the amount of p-RNA was doubled, and the r-RNA was increased b...

1. An increase in polyamine concentration, caused by inhibiting the amine oxidase activities with iproniazid, increased the incorporation of [3H]orotic acid into chick-embryo RNA and DNA. On the other hand, a decrease in polyamine concentration, obtained by causing an increase in amine oxidase activities, decreased [3H]orotic acid incorporation into nucleic acids. This was particularly evident ...

2. The nuclei in vitro incorporate [2-14C]glycine and [1-14C]valine into nuclear protein and [6-14C]orotic acid and [8-14C]adenine into nucleic acids. 3. Anoxia and 2,4-dinitrophenol inhibit the incorporation of the radioactive precursors into nuclear proteins and nucleic acids. Chlorpromazine inhibits the incorporation of valine, but has no effect on the incorporation of orotic acid. 4. The sp...