Growth on Histidine and Lysine Injected Subcutaneously or Intraperitoneally

Recently a controversy has arisen in the literature as to whether or not tryptophane can be utilized for growth when administered subcutaneously. The evidence, is divided, but favors the affirmative somewhat. The fundamental question involved embraces also other amino acids, especially the essential ones. We have therefore tested the growth-promoting abilities of histidine and lysine when subcutaneously or intraperitoneally administered to rats fed diets deficient in histidine or lysine respectively, but otherwise adequate. In every case growth resulted