Experimental anemias in the rat; II. The effect of various sulfonamides in producing a pteroylglutamic acid deficiency and the pteroylglutamic acid activity of test substances.

By E. KODICEK, M.D., Ph.D., AND K. J. CARPENTER, MA., Ph.D. I N OUR previous paper’ we described the development of a macrocytic normochromic anemia in rats fed on synthetic diets containing i per cent sulfasuxidine, and maintained in a state of chronic pteroylglutamic acid (PGA) deficiency. The blood picture of these rats was similar to the nutritional anemias of other species, caused by a PGA deficiency. Although sulfasuxidine was effective in producing anemia, it caused certain pathologic changes, such as the deposition of stones in the urinary tract, which were due to the slightly soluble sulfasuxidine being absorbed in small amounts into the blood stream and subsequently deposited during excretion. Other sulfonamides, namely the less soluble sulfaguanidine, phthalylsulfathiazole and the more soluble sulfathiazole, were therefore studied in a further series of experiments. Sulfaguanidine and phthalylsulfathiazole have been successfully used by a number of workers.’’ Sulfaguanidine, however, was found by Slater#{176} to be toxic for rats and had to be replaced by sulfasuxidine. The more soluble sulfathiazole, in