An Interrelation of Pteroylglutamic Acid, Vitamin B12 and the Monkey Anti-Anemia Factor

Abstract

A deficiency of PGA was created in young rhesus monkeys by means of a purified diet. Signs characteristic of a lack of the monkey anti-anemia factor accompanied those of the primary deficiency. Remission of the monkey anti-anemia factor deficiency syndrome was obtained by the oral administration of PGA at a level 10 times the minimum daily requirement. Remission for a limited period was also obtained with a 60% methanol extract of liver supplying only 4 μg each of PGA and vitamin B₁₂ per day. Eventually PGA had to be supplied to maintain normal growth rate and blood picture, but it was required in much smaller amounts than when the methanol extract of liver, which is a good source of the monkey anti-anemia factor, was not employed. Vitamin B₁₂ produced responses only in the less-deficient monkeys and probably acted in conjunction with vitamin C to stimulate the synthesis of PGA. A relationship exists among PGA, vitamin C, vitamin B₁₂ and the monkey anti-anemia factor, although the latter two substances are not ordinarily required in the diet of the normal monkey. At high levels PGA appears to be capable of satisfying any requirement that may exist in a PGA-deficient monkey for vitamin B₁₂ or the factor or factors present in methanol extract of liver (the monkey anti-anemia factor).