Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rotavirus enteritis is the leading cause of diarrhea in infants worldwide. A research priority of the World Health Organization is to develop oral rehydration solutions containing amino acids or other additives that will stimulate intestinal absorption more efficiently than the current glucose-based oral rehydration solutions. Glutamine is the principal metabolic fuel of the small bowel and a putative stimulator of mucosal repair. This report describes the transport response to mucosal L-glutamine following intestinal injury caused by porcine rotavirus. Peak symptoms and mucosal damage were observed 2-7 days after oral rotavirus inoculation. In vitro transport studies of the maximally injured region, the midjejunum (80% reduction in lactase), surprisingly, showed transport responses to L-glutamine (30 mmol/L) and L-alanine (30 mmol/L) that were similar qualitatively and quantitatively to those observed in control tissue. Subsequent application of mucosal D-glucose (30 mmol/L) caused additional stimulation of electrogenic Na+ transport, but the response to glucose was blunted (P less than 0.05) in the infected tissues. Glutamine and alanine enhanced Na+ absorption to a similar degree (2-2.5 muEq.cm-2.h-1), but glutamine stimulated equal amounts of electrogenic and electroneutral NaCl absorption, whereas alanine had no significant effect on net Cl- flux. Glutamine is a potentially useful substrate for investigation in oral rehydration solutions for infant diarrhea.
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PMID:L-glutamine stimulates jejunal sodium and chloride absorption in pig rotavirus enteritis. 188 9

Gut atrophy develops during prolonged total parenteral nutrition (TPN). TPN solutions do not contain glutamine, an energy substrate of the intestinal tract. This study evaluated the effect of addition of L-glutamine to TPN on gut nitrogen content, histology, and disaccharidase enzyme activity. Five groups of six Fisher 344 rats received rat chow, D5W, TPN (23% calories as lipid), or TPN with 1 or 2% L-glutamine. Animals given TPN received 30 kcal and 0.22 g nitrogen/100 g/day. Metabolic cages allowed nitrogen balance for each group. After 6 days infusion, stomach, small bowel, and colon were assayed for total nitrogen and sucrase, lactase, and maltase activity. Mucosal height and fatty infiltration of the liver were determined from histologic sections. Adding either 1 or 2% L-glutamine resulted in no toxic clinical effects. Glutamine preserved intestinal nitrogen content of the stomach and colon compared to standard TPN and increased nitrogen content of small bowel to greater than that in chow-fed animals. Glutamine maintained mucosal height of the stomach and colon, but was no better than TPN alone in maintenance of small bowel mucosal height. One percent glutamine increased and standard TPN depressed maltase activity compared to chow. Standard TPN and 1% glutamine both stimulated sucrase and lactase activity compared to chow. Addition of 1 or 2% glutamine protected the liver from fatty infiltration seen with standard TPN. These studies would suggest the addition of glutamine might be beneficial during provision of standard total parenteral nutrition.
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PMID:Use of L-glutamine in total parenteral nutrition. 313 88

Glutamine supplementation has been advocated for patients requiring parenteral nutritional support. However, the direct effect of glutamine on neoplastic cells is poorly understood. We therefore investigated the effects of glutamine on the proliferation, differentiation, and cell-matrix interactions of two human colon carcinoma cell lines (Caco-2 and SW620) adapted to glutamine-free media. Doubling times were calculated by logarithmic transformation of serial cell counts. Alkaline phosphatase, cathepsin C (dipeptidyl peptidase), lactase, and isomaltase expression (markers of differentiation) were assayed by digestion of synthetic substrates. Adhesion to matrix proteins was assessed by colorimetric quantitation of toluidine blue staining of adherent cells. Surface expression of Caco-2 receptors for matrix proteins (integrins) was studied by biotinylation and immunoprecipitation with specific antibodies. Glutamine (1-10 mM) dose-dependently stimulated Caco-2 proliferation on all matrices studied with maximal effect at 7 mM. For instance, Caco-2 doubling time on collagen IV decreased by 57 +/- 0.2% (SE) (P < 0.001). Glutamine inhibited the expression of all four digestive enzymes with maximal inhibition ranging from 10 to 40% (P < 0.05 for all). Adhesion to matrix proteins was markedly diminished (51 +/- 1%, P < 0.01) by glutamine (5 mM) treatment, correlating with decreased alpha 2 and beta 1 integrin subunit surface expression. Glutamine had similar effects on SW620 cells, stimulating proliferation, inhibiting digestive enzyme expression, and diminishing both adhesion and integrin surface expression. Glutamine supplementation modulates the phenotype of at least two human colon carcinoma cell lines, increasing proliferation, decreasing differentiation, and decreasing adhesion to matrix proteins in association with decreased integrin expression. Although the mechanisms of these effects await elucidation, such characteristics would appear to predict more aggressive tumor behavior and raise the possibility that nutritional supplementation with glutamine may be deleterious in patients with cancer.
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PMID:Glutamine modulates phenotype and stimulates proliferation in human colon cancer cell lines. 795 30

Cryptosporidium parvum produces a prolonged watery diarrhea unresponsive to conventional antimicrobials. Because of reported efficacy of antibody-based immunotherapy, we studied the effect of inexpensive, commercially available oral bovine serum concentrate (BSC) in experimental cryptosporidiosis. Twenty-four calves were treated with 57 g/d BSC (n = 12) or soy protein (n = 12) added to their standard whey protein-based milk replacer (227 g/2 L twice daily). Of the 24, 9 were also treated with L-glutamine (GLN), 8 g/L (50 mM) in the milk (5 calves in the BSC group and 4 in the soy group). Animals were inoculated with 10(8) cryptosporidium oocysts per os on d 8 of life and received oral rehydration on d 12-14. Eight uninfected controls were treated with BSC or soy protein. Fecal and urine volume and urinary Cr-EDTA excretion were measured. Animals were killed on d 18 of life. Cryptosporidiosis induced severe watery diarrhea lasting >9 d and produced a 25% increase in intestinal permeability, a 33% decrease in villous surface area, and a 40% reduction in mucosal lactase specific activity. Glutamine treatment had no effect on the diarrhea or any of the intestinal tests; and therefore pooled data were used to compare the 12 calves treated with BSC with the 12 treated with soy. In animals receiving BSC, peak diarrheal volume and intestinal permeability were reduced 33%, fewer oocysts were shed, intestinal crypts were significantly deeper, and villous surface area returned to normal by 9 d after infection (all p <or= 0.05). BSC should be studied as a treatment for human cryptosporidiosis.
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PMID:Oral bovine serum concentrate improves cryptosporidial enteritis in calves. 1186 44