American Journal of Clinical Nutrition, Vol 26, 873-875, Copyright © 1973 by The American Society for Clinical Nutrition, Inc.

Defective propionate oxidation in leukocytes of vitamin B₁₂-deficient pigs: in vitro correction

¹ From the Department of Human Genetics, Yale University School of Medicine, New Haven, Connecticut 06510

We have studied the oxidation of propionate-3-¹⁴C to ¹⁴CO₂ by peripheral blood leukocytes from vitamin B₁₂-deficient miniature pigs. Four weanling pigs were fed a synthetic diet deficient in vitamin B₁₂ starting at age 10 days. Two of these pigs were given weekly injections of cyanocobalamin. Serum B₁₂ concentrations were distinctly lower in the untreated pigs by the age of 2 months. At age 4 months, the B₁₂-deficient pigs demonstrated neither megaloblastic anemia nor methylmalonicaciduria, but the ability of their leukocytes to oxidize propionate was markedly impaired. Prolonged preincubation of their leukocytes in vitro with cyanocobalamin, hydroxocobalamin, 5'-deoxyadenosyl-cobalamin, or methylcobalamin led to partial correction of this metabolic block. We conclude that impaired propionate oxidation by leukocytes provides early biochemical evidence of vitamin B₁₂ deficiency.