Abstract
The activities of RNA polymerases I, II and III in a sodium deoxycholate(DOC)-treated enzyme preparation were differentially determined using 3 combinations of assay conditions (metal ion; Mg2+ or Mn2+, (NH4)2SO4 and .alpha.-amanitin). Ginsenoside-Rb1 enhanced, while -Rc repressed, the activities of RNA polymerases I and II; 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 .apprx. +70% at 2 h, and that of RNA polymerase II activity was +40% at 3 h after the injection of Rb1. Actinomycin D and cycloheximide both blocked the increase in RNA polymerase I activity on treatment with ginsenoside-Rb1. Increased activity of RNA polymerase II was blocked by actinomycin D but not by cycloheximide. Apparently there is transcriptional regulation in the enhancement by ginsenoside-Rb1 of RNA polymerase activities I and II, though the mechanisms may differ in detail.