Abstract
A decrease in serum folate levels of rats receiving diphenylhydantoin was partly due to a reflexion of a decreased level of N5-methyltetrahydrofolate in the liver of these rats. The decreased levels of Nb-methyltetrahydrofolate in the liver was resulted from an elevation of the N5-methyltetrahydrofolate-homocysteine transmethylase activity. The elevation of the enzyme activity was resulted from (a) an increased production of the N5-methyltetrahydrofolate-homocysteine transmethylase apoenzyme by induction following diphenylhydantoin administration, and (b) a probably increased supply with vitamin B12 to the liver which was mediated by an increased level of the serum transcobalamin II due to diphenylhydantoin administration.
