Alterations in Circulating Folate Induced by B 12 Deficiency. ∗

Abstract

Summary

Clinical B₁₂ deficiency is further characterized by accumulation of S. fae-calis-active folyl monoglutamates after 5 mg of oral PGA. B₁₂ treatment lowers S. faecalis activity to normal implying that B₁₂ decreased folyl monoglutamate activity; neither normal nor folate-depleted subjects showed this effect. Our findings suggest that B₁₂ deficiency interferes with formimino transfer-ase, and that principally PGA, not N ⁵-methyl THF, accumulates during B₁₂ deficiency.

We thank Mrs. Susan Feingold for her assistance in this study, and Dr. J. M. Ruegsegger, Lederle Laboratories, Pearl River, N. Y., for gifts of folates.