Pteroylglutamic acid malabsorption in tropical sprue

Pteroylglutamic acid (PGA) absorption was assessed in ten untreated tropical sprue (TS) and eight control subjects utilizing a marker perfusion technique. Physiologic concentrations of the vitamin (25 ng/ml) dissolved in iso-osmotic solutions containing either mannitol of glucose at a concentration of 55.6 mM were perfused on each subject on two consecutive days. A statistically significant difference in PGA absorption between TS and control subjects was obtained only when glucose was present in the perfusate. Thus, unequivocal malabsorption of PGA is demonstrable in all subjects with TS when more refined techniques than the ones applied heretofore are utilized.