Effect of Folic Acid, "4-Amino" Folic Acids and Related Substances on Growth of Chick Embryo.

Abstract

The 4-amino pteroylglutamic acids profoundly inhibit the growth of the chick embryo, with the production of developmental abnormalities. These compounds are active in the range of 0.0036-0.005 mg. per egg and their actions are not prevented by a large dose of folic acid. The "4-amino" folic acids with aspartic acid, threonine, and alanine substituted for the glutamic acid are considerably less toxic, but produce similar effects. Other compounds allied to folic acid are relatively non-toxic and have no growth-inhibiting activity. 2,6-diaminopurine at LD50 doses is not an active growth inhibitor but produces a pale embryo, presumably deficient in hemoglobin.