Jejunal perfusion of simple and conjugated folates in celiac sprue.

Abstract

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.

Jejunal Perfusion of Simple and Conjugated Folates in Tropical Sprue

“…Thus, the malabsorption of conjugated folates may result from decreased mucosal hydrolysis, decreased intestinal transport of pteroylmonoglutamate, or a combination of these factors. The recent development of more refined techniques to determine folate conjugase activity in intestinal mucosa (7) and to measure intestinal luminal disappearance, as well as luminal degradation products of pure synthetic conjugated folate (8), prompted us to study the simultaneous absorption of separately labeled simple and conjugated folates in six patients with tropical sprue. Center of the University of Puerto Rico School of Medicine, patients were placed on a 80 g fat diet.…”

“…The counting efficiencies were 65% for "C and 25%o for 3H. Disappearance of each label from the 30-cm perfused segment was calculated as previously described (8). Transintestinal movement of water, sodium, and chloride was calculated for the distal 15-cm segment using conventional formulas (18).…”

“…Transintestinal movement of water, sodium, and chloride was calculated for the distal 15-cm segment using conventional formulas (18). The frozen and acidified remaining aliquot was thawed, neutralized, and then subjected to column chromatography on DEAE cellulose chloride with a linear sodium gradient to separate degradation products of ['C]PG-7, as previously described (8).…”

Folates: Key Nutrients to Remember

“…Folic acid or PGA is practically no present as such in nature where it exists only as traces in human tissues and foods, it represents the purified, stable form used in pharmaceutical preparations most of which is as Polyglutamates (PG) 15,[18][19][20][21] . Folic acid is a yellow, watersoluble crystalline powder that is sensitive to air, light and heat; this explains the losses observed during cooking 22 .…”

“…The polyglutamate forms are converted to monoglutamate derivatives (MG) by action of digestive proteases 21,29 . Only MG forms crossed the enterocyte's barrier as confirmed by several works in animals 30,31 , in humans 14,29,32,33 and in vitro 15,34 .…”