Milton Silverman

Activity of Citrovorum Factor it or the Chick.

Summary 1. Crystalline citrovorum factor obtained from horse liver was approximately as active when injected as pteroylglutamic acid in counteracting folic acid deficiency in the chick. Under the same conditions citrovorum factor appeared to be somewhat more active than leucovorin. 2. Citrovorum factor leucovorin, and folinic acid-SF when given in the diet were substantially less active than pteroylglutamic acid.

Influence of vitamin B12 on the urinary excretion of folic acid metabolites by the rat

Abstract The active metabolites of folic acid which appear in the urine of the rat after the injection of folic acid (tetrahydrofolic acid and formylated derivatives) are not diminished in vitamin B 12 deficiency. It is concluded that vitamin B 12 is not directly involved in the reduction or formylation of folic acid.

Excretion of a histidine metabolite by the rat.

Summary A histidine metabolite, isolated from the urine of folic acid deficient rats and postulated to be α-formamidinoglutaric acid, is excreted unchanged after subcutaneous injection into normal rats.