The Fate of Orally and Parenterally Administered Folates

Abstract

The fate of orally and parenterally administered folic acid, folinic acid, Diopterin and Teropterin was followed in serum and urine. Folate activities in serum and urine were charted by chromatography and bioautography, exploiting the differential folate responses of Lactobacillus casei, Pediococcus cerevisiae and Streptococcus faecalis. The outstanding findings are the conversion of ingested folinic acid into a folate inactive for P. cerevisiae and S. faecalis but active for L. casei and the conversion of orally administered Diopterin into an L. casei active folate, although Diopterin is inactive in vitro. Comparisons of the results obtained with serum and urine indicate that folic acid is the principal metabolic end product in the urine after pteroylmonoglutamate or pteroylpolyglutamate administration.