A rapid increase in formiminotransferase activity of liver during infancy.

In a preceding paper of ours,1 it was reported that a relatively large amount of formiminoglutamic acid (more than O.1ƒÊ mole/ml) was excreted into urine of infants with the normal serum folate activity when an oral dose of L-histidine chloride (0.33g per kg of bodyweight) was given, and it was also suggested that this might be due to an immaturity of the formiminotransferase activity of the liver in infancy. The purpose of this article is to demonstrate that, in rats and mice, the activity of the liver formiminotransferase was low at birth and then rapidly increased during infancy.