Jejunal perfusion of simple and conjugated folates in celiac sprue.

A C T The intestinal absorption of [3H ]- pteroylmonoglutamate (simple folic acid) and pteroyl- ,u[14C]glutamyl-y-hexaglutamate ([14C]PG-7, conju- gated folic acid) was assessed by the method ofjejunal perfusion in five patients with proven celiac sprue who were studied after a gluten-containing or a gluten-free diet, and in nine normal subjects. The luminal disap- pearance of each folate was markedly impaired after exposure of the patients to dietary gluten and improved by gluten restriction, but not to within the range found in the normal subjects. In each experiment, column chromatography ofthe luminal aspirates revealed simi- lar spectra ofhydrolytic products of ["4C]PG-7, whereas the fraction of the distal aspirate chromatogram appear- ing as pteroyl-pu[14C]glutamyl-y-monoglutamate ([14C]- PG-1) was similar in all three groups. By accounting for the variable effects of absorption on the luminal appearance of [U4C]PG-1 and by correcting for mucosal hydrolysis which was not followed by release of [I4C]PG-1 to the luminal contents, the calculated rate of in vivo hydrolysis of ["4C]PG-7 to ["4C]PG-1 was found impaired in both celiac sprue groups, with significant improvement on treatment. In mucosal biopsies from the sprue patients, the in vitro activity of folate conjugase in whole homogenates was higher and the activity of disaccharidase lower than in a group of 12 normal mucosal biopsies. These in vitro data suggest that the predominant cellular loca- tion of mucosal folate conjugase is different from that of disaccharidase, whereas comparison with the re- This work was presented at meetings of the American