A B S T R A C T The intestinal absorption of [3H ]-pteroylmonoglutamate (simple folic acid) and pteroyl-,u[14C]glutamyl-y-hexaglutamate ([14C]PG-7, conjugated 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 disappearance 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 similar spectra ofhydrolytic products of [ sults of in vivo hydrolysis suggests that measurement of the enzyme in whole mucosal homogenates overestimates its significant digestive activity. The present studies indicate that (a) the mucosal lesion of celiac sprue significantly limits the intestinal absorption of both simple and conjugated folate, and (b) malabsorption of conjugated folate results from a combination of impaired hydrolysis and decreased mucosal uptake of hydrolytic product.

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