Stimulating Action of Tissue Extracts on Regenerative Processes

Abstract

By means of systematic injections of tissue extracts one may obtain stimulation of regeneration of muscles (in frogs) and liver (in frogs, rabbits, guinea-pigs). Such extracts, however, apparently only influence homologous tissue. The influence of extracts does not show any class specificity. On the con-trary, the stimulation of regeneration of frog muscle and liver is more effectively produced by corresponding extracts of hen tissues than by those of the frog. Aqueous extracts are as active as those obtained with isotonic saline. Heating to 60° C. for 5 minutes inactivates the extract. The analysis of our data and of those published elsewhere leads to the conclusion that the stimulating agent is a water-soluble protein fraction, or that it is some substance (e.g. RNA) forming a rather strong complex with this fraction.