Some Aspects of the Metabolism of Antimegaloblastic Substances in Man

1. When the sera of pernicious anemia patients or controls were heated at 100 C. for 30 minutes, they developed the ability to support the growth of L. leichmannii by virtue of some substance other than vitamin B₁₂. It seemed likely, however, that following the administration of the vitamin, such heating also liberated free B₁₂ in the serum from a combined form.

2. The L. leichmannii assay did not appear to be satisfactory for showing possible difference in the levels of vitamin B₁₂ in the urines or sera of pernicious anemia patients and controls.

3. Parenterally administered vitamin B₁₂ did not cause any measurable rise in the serum level of folic acid or citrovorum factor in pernicious anemia patients or controls.

4. The synthetic folic acid conjugates pteroyldiglutamic acid and pteroyltriglutamic acid appeared in the sera and urines of pernicious anemia patients as pteroylglutamic acid or some related substance with folic acid activity for S. faecalis.

5. Orally administered citrovorum factor appeared to be largely converted by the gastric juice to folic acid if free hydrochloric acid was present. When administered parenterally, however, citrovorum factor was excreted in the urine largely unchanged.