Succinylsulfathiazole and a Rat Growth Factor in Liver

Abstract

Young rats on a synthetic diet containing purified casein and all members of the vitamin B group except pteroylglutamic acid and vitamin B₁₂ grew well. The addition of succinylsulfathiazole produced the usual results, namely, failure of growth, leukocytopenia with the granulocytes affected more than the other cells, and finally death. The inclusion of pteroylglutamic acid in the succinylsulfathiazole diet corrected the blood dyscrasia and prevented the death of the animals but failed to restore growth completely. Increasing the amount of pteroylglutamic acid did not change the picture. Animals given succinylsulfathiazole plus a crude liver extract had normal blood and grew at a rapid rate. Doubling the amount of 2-methyl-1,4-naphthoquinone and of the dietary B vitamins except choline did not increase the growth of rats given succinylsulfathiazole and pteroylglutamic acid. The subcutaneous injection of 0.02 ml of a purified antipernicious anemia liver preparation in rats on the latter regimen produced very good growth. The probable relation of this growth factor found in liver to vitamin B₁₂ is discussed.