INTESTINAL-ABSORPTION OF FOLATES

Dietary folates, existing primarily in the form of pteroylpolyglutamates, are absorbed in the jejunum by a process involving hydrolysis and subsequent intestinal transport of pterolmonoglutamyl folate. Current evidence indicates that one (or more) intestinal mucosal enzyme(s), termed folate conjugase, is required for the hydrolysis of pteroylpolyglutamate to pteroylmonoglutamyl folate. Unresolved controversies include the mucosal location of hydrolysis (surface versus (intracellular), whether the transport for pteroylmonoglutamate is active or passive, and the relation of intestinal mucosal metabolism of pteroylmonoglutamate to its intestinal transport.