[Effect of actinomycin D on cell proliferation induced by phytohemagglutinin in human lymphocytes]

Actinomycin D at a dose inhibiting the synthesis of ribosomal RNA (0.15 MUG/ML) BLOCKS THE TRANSITION OF CELLS INTO ACTIVE PROLIFERATION DURING THE FIRST 6 HOURS AFTER PHYTOHAEMAGGLUTININ TREATMENT. The effect of actinomycin D becomes weaker as the cells proceed through the prereplicative period. 1 mug/ml actinomycin D blocks the synthesis of all RNSs. It has been found that actinomycin D at this concentration blocks the transition of cells into the proliferation during the entire prereplicative period.