Abstract
The activities of ribonucleic acid (RNA) polymerases I, II and III in a sodium deoxycholate (DOC)-treated enzyme preparation have been differentially determined using three combinations of assay conditions (metal ion ; Mg2+ or Mn2+, (NH4)2SO4 and α-amanitin). Ginsenoside-Rb1 enhanced, while -Rc repressed, the activities of RNA polymerases I and II, whereas both had no effect on that of RNA polymerase III. Rb1-treated rats showed different profiles of stimulation of RNA polymerases I and II ; the maximum increase of RNA polymerase I activity was about +70% at 2 hr, and that of RNA polymerase II activity was +40% at 3 hr after the injection of Rb1. Actinomycin D and cycloheximide both blocked the increase in RNA polymerase I activity on treatment with ginsenoside-Rb1. On the other hand, increased activity of RNA polymerase II was blocked by actinomycin D but not by cycloheximide. These results suggest transcriptional regulation in the enhancement by ginsenoside-Rb1 of RNA polymerase activities I and II, though the mechanisms may differ in detail.
