Study of the Therapeutic Effect on Irradiated Mice of Substances Contained in RNA Preparations

Summary Preparations of various types of RNAs injected i.p. (2-5 mg/0·5 ml.) before or after irradiation of mice with lethal or sub-lethal doses produce a significant increase in the survival rate. No difference in the therapeutic effect was observed between homologous RNA (from sucklings) and heterologous RNA (from rat liver or yeast). Extraction methods which favour the molecular integrity of the RNA give active preparations. However, the active substance seems not to be a polyribonucleotide nature although bound to substances in the RNA preparations since it is liberated during dialysis against water. The therapeutic effect does not seem to be related to the presence either of contaminating polypeptides or oligonucleotides. The activity of lipopolysaccharides is discussed.