TY - JOUR
T1 - Human intestinal folate conjugase
T2 - Adaptation after jejunoileal bypass
AU - Reisenauer, A. M.
AU - Halsted, C. H.
AU - Jacobs, L. R.
AU - Wolfe, B. M.
PY - 1985
Y1 - 1985
N2 - During intestinal absorption, dietary polyglutamyl folates are hydrolyzed to monoglutamyl folates by pteroylpolyglutamate hydrolase (folate conjugase). This enzyme is present in the brush border and intracellular fractions of human jejunal mucosa. We compared the activities of brush border and intracellular folate conjugase (BBFC and ICFC), and other mucosal enzymes in the jejunum in continuity and bypassed loop in nine patients who underwent intestinal reconstitution operations 3 to 9 yr after jejunoileal bypass. Control jejunum was obtained from seven obese patients undergoing gastric bypass surgery. Jejunal morphometry showed mucosal hyperplasia with taller villi, larger crypts, and no change in cell size in the jejunum in continuity as compared to control or bypass jejunum. In brush border fractions, specific activities of sucrase and BBFC were significantly greater in the jejunum in continuity than in the control or bypass jejunum. In contrast, the specific activities of the other brush border and intracellular enzymes, including ICFC, were similar in all three segments. This is the first evidence that BBFC, like sucrase, adapts to luminal nutrition. The difference in response to BBFC and ICFC to diet and/or pancreato-biliary secretions provides evidence that these are distinct enzymes which are regulated by different mechanisms.
AB - During intestinal absorption, dietary polyglutamyl folates are hydrolyzed to monoglutamyl folates by pteroylpolyglutamate hydrolase (folate conjugase). This enzyme is present in the brush border and intracellular fractions of human jejunal mucosa. We compared the activities of brush border and intracellular folate conjugase (BBFC and ICFC), and other mucosal enzymes in the jejunum in continuity and bypassed loop in nine patients who underwent intestinal reconstitution operations 3 to 9 yr after jejunoileal bypass. Control jejunum was obtained from seven obese patients undergoing gastric bypass surgery. Jejunal morphometry showed mucosal hyperplasia with taller villi, larger crypts, and no change in cell size in the jejunum in continuity as compared to control or bypass jejunum. In brush border fractions, specific activities of sucrase and BBFC were significantly greater in the jejunum in continuity than in the control or bypass jejunum. In contrast, the specific activities of the other brush border and intracellular enzymes, including ICFC, were similar in all three segments. This is the first evidence that BBFC, like sucrase, adapts to luminal nutrition. The difference in response to BBFC and ICFC to diet and/or pancreato-biliary secretions provides evidence that these are distinct enzymes which are regulated by different mechanisms.
UR - http://www.scopus.com/inward/record.url?scp=0021970873&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0021970873&partnerID=8YFLogxK
U2 - 10.1093/ajcn/42.4.660
DO - 10.1093/ajcn/42.4.660
M3 - Article
C2 - 3931452
AN - SCOPUS:0021970873
SN - 0002-9165
VL - 42
SP - 660
EP - 665
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
IS - 4
ER -