Use of Sulfaguanidine in Nutrition Experiments.

It has been shown that on a purified basal ration 0.5% sulfaguanidine greatly reduces the growth rate of young rats. When liver extract is fed with 0.5% sulfaguanidine, optimum growth is obtained. p-amino benzoic acid fed with 0.5% sulfaguanidine from the beginning of an experiment gives a definite growth response, but gives no response during the first week when fed to rats which have received sulfaguanidine alone for several weeks. The bearing of these results upon the possible synthesis of unidentified rat growth factors by intestinal bacteria is discussed.