An Effect of Vitamin B12 Deficiency in Tissue Culture

Rat glial cells were grown in tissue culture in vitamin B12-deficient medium. As the intracellular level of coenzyme B12 decreased, the cells made increasing amounts of two unusual fatty acids. The fatty acids were unbranched acids with 15 and 17 carbon atoms and arose as the cells progressively lost the ability to metabolize propionic acid through the B12-requiring methylmalonyl-CoA mutase reaction. The levels of the 15- and 17-carbon acids returned to normal when the cultures were supplemented with vitamin B12. The possible importance of similar fatty acid changes in human vitamin B12 deficiency and in disorders of 3- and 4- carbon acid metabolism is speculated.