Formate metabolism in the vitamin B12-deficient rat

Abstract

An observed decrease in liver folic acid levels in the hyperthyroid rat is not corrected by vitamin B12 administration. It is also not accompanied by any clear-cut decrease in the incorporation of [Cl4]formate in vivo into the purines of liver acid-soluble nucleotides. It is concluded that incorporation of formate into the purines of rat liver acid-soluble nucleotides is independent of mild disturbances in folic acid metabolism. Vitamin B12 administration to a vitamin B12 deficient rat markedly decreased the incorporation of [C14]formate in vivo into liver acid-soluble nucleotides. This could be partly explained in terms of the accompanying increase in the oxidation of formate studied in vitro. Vitamin B12 has a role, directly or indirectly, in the oxidation of formate. In rat liver, oxidation of formate may not necessarily be catalase-linked.