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)

Suckling mice infected with reovirus type 3 were examined for changes in the epithelial brush border of the small intestine. After 3 days of infection with reovirus type 3, no significant changes were found in intestinal morphology or activity of any enzymes tested. After 6 days, villi were shortened and blunted with lymphangiectatic lesions and mild mononuclear infiltration in the lamina propria. In addition, there was a significant decrease in lactase (P < 0.001) and enterokinase activity (P < 0.05). However, there were no significant changes in the activities of alkaline phosphatase. In contrast, maltase (P < 0.001) and leucine aminopeptidase (P < 0.05) activities in the infected mice were significantly increased. These data suggest that brush border enzymes are affected differently by reovirus infection.
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PMID:Small intestinal epithelial brush border enzymatic changes in suckling mice infected with reovirus type 3. 625 Jan 21

Preparations of isolated brush border plasma membrane of Hymenolepis diminuta and H. microstoma possess the following enzymatic activities: alkaline phosphohydrolase (E.C. 3.1.3.1); Type I phosphodiesterase (E.E. 3.1.4.1); ribonuclease (E.C. 3.1.4.22); adenosine triphosphatase (E.C. 3.6.1.3); and 5'-nucleotidase (E.C. 3.1.3.5). The following enzymatic activities could not be demonstrated in either membrane preparation: Type II phosphodiesterase (E.C. 3.1.4.18); cyclic adenosine-3', 5'-monophosphate phosphodiesterase (E.C. 3.1.4.17); leucine aminopeptidase (E.C. 3.4.11.1); maltase (alpha-glucosidase; E.C. 3.2.1.20); and lactase (beta-galactosidase; E.C. 3.2.1.23). These data generally agree with those of previous studies in which similar membrane-bound enzymes were demonstrated in intact (living) worms.
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PMID:A comparison of membrane-bound enzymes of the isolated brush border plasma membranes of the cestodes of Hymenolepis diminuta and H. microstoma. 628 Jan 22

Small intestinal development was followed in rats from 17 to 28 days of age in order to evaluate the interactions of diets, genetic preprogramming, and hormones in influencing developmental changes. Control pups, weaned naturally at 21-24 days, showed a gradual increase in body weight, intestinal length, and segmental mucosal weight, total DNA, and protein content. In contrast, pups weaned at 17 days showed an immediate increase in intestinal length, decrease in lactase, and precocious increase in sucrase and maltase. The changes in segmental mucosal weight, DNA and protein contents, however, paralleled that of controls. Pups nursed up to 25 days had a smaller body weight, shorter intestine, lighter mucosa, and lesser mucosal protein content. They showed no significant delay in the increase in sucrase and maltase together with a persistent higher level of lactase. Enterokinase and leucine aminopeptidase showed little change irrespective of the dietary modifications. Significant increases in segmental mucosal mass, DNA, and protein contents during the studied period were seen in all animals. At 19 days, early weaned pups had serum levels of corticosteroids about 3 times that of control or prolonged nursed pups. The results support the concept of an inherent biologic program as a basic control of intestinal ontogeny whereas dietary changes seem to have a modifying role and act directly, or in concert with, hormonal changes.
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PMID:Early weanling and precocious development of small intestine in rats: genetic, dietary or hormonal control. 635 Oct 6

Fasting reduced small intestinal length. It also decreased mucosal weight, DNA and protein content, and concentrations of enterokinase, maltase, and sucrase in both duodenal and jejunal segments. In contrast, the concentrations of lactase and leucine aminopeptidase were not affected. Concomitantly, serum insulin levels dropped to one-fifth of the control levels while serum glucose concentrations showed a lesser degree of reduction. Glucose supplementation alone raised the serum insulin level, prevented the decrease in DNA content, and showed a protective effect on mucosal protein, mucosal weight, mucosal thickness, and villus height. Glucose also protected the sucrase and maltase concentrations; more significantly for maltase in the jejunal segment. Insulin alone, although it increased the serum insulin level to that found with glucose supplementation alone, had no protective effect on the loss in protein, DNA, and most enzymes except for maltase concentration in the jejunal segment. Addition of insulin to glucose did not modify the glucose effect on the contents of DNA, protein, and concentrations of sucrase and maltase. These results suggest that the glucose effect on the mucosa is not mediated by insulin. In addition, the retention of both maltase and sucrase activities through only glucose supplementation suggests the loss of maltase and sucrase in fasting is due to nutrient rather than specific substrate restriction.
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PMID:Effect of glucose and insulin on small intestinal brush border enzymes in fasted rats. 640 48

The effect of dietary thiamin deficiency has been studied on intestinal functions and chemical composition of brush border membranes in rats. Intestinal uptake of glucose, glycine, alanine, and leucine was significantly stimulated in thiamin deficiency compared to pair-fed control group. Studies with glucose and glycine revealed that stimulation of the absorption process occurs only in the presence of Na+ but not in its absence. Km measured in the presence of 140 mM Na+ for glucose and glycine uptakes was reduced by 56 and 41%, respectively, but Vmax remained unaltered in vitamin deficiency. There was no change in these parameters in Na+-free medium (Km = 31.3 and 23.3 mM; Vmax = 17.2 to 19.7 and 13.5 to 16.4 mumol/10 min/g wet tissue, respectively) under these conditions. The activities of brush border sucrase, lactase, maltase, alkaline phosphatase, and leucine aminopeptidase were reduced by 42 to 66% in thiamin deficiency, compared to pair-fed controls. Kinetic studies with sucrase and alkaline phosphatase evinced that a decrease in Vmax (61 and 64%, respectively) with no change in Km (33.8 and 4.3 mM, respectively) was responsible for observed impairment in the enzyme activities in thiamin deficiency. Microvillus membrane proteins expressed on dry membrane basis were reduced by 20% in thiamin-deficient intestine. There was no difference in membrane sialic acid, cholesterol, phospholipids, and triglycerides fractions under these conditions. It is suggested that thinning of the microvillus membrane may be implicated in observed aberrations of intestinal functions in thiamin-deprived animals.
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PMID:Effect of dietary thiamin deficiency on intestinal functions in rats. 646 54

Imposition of undernutrition during the suckling period considerably enhanced the intestinal uptake of D-glucose and glycine compared to a control group. Brush border sucrase, and alkaline phosphatase activities were drastically reduced while lactase and leucine amino peptidase levels were significantly elevated at weaning in nutritionally deprived pups as compared to control animals. Cortisone administration to undernourished rats depressed the uptake of D-glucose but stimulated that of glycine. Thyroxine treatment to undernourished animals reduced the uptake of glucose but had no effect on glycine absorption. Brush border sucrase and alkaline phosphatase activities were stimulated in cortisone- or thyroxine-injected undernourished rats but lactase activity was depressed under these conditions. Leucine aminopeptidase activity remained unaffected in cortisone- or thyroxine-administered undernourished pups.
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PMID:Alterations in intestinal function in response to thyroxine and cortisone administration in undernourished rats. 713 57

The effect of undernutrition during suckling has been investigated on the brush border enzymes and the intestinal uptake of D-glucose and glycine in rats at weaning. The brush border sucrase and alkaline phosphatase activities were drastically reduced, but lactase and leucine aminopeptidase levels were significantly elevated in the intestine of nutritionally deprived pups compared to controls. The uptake of D-glucose and glycine in undernourished rats was also augmented. The chemical composition of the brush border membrane analyzed in nutritionally deficient animals revealed an enhancement of the membrane protein, sialic acid, cholesterol, and phospholipids compared to the control group. [U-14C]D-Glucose incorporation into lipid constituents of the membrane suggested that the observed enhancement of the membrane lipids is the result of an increased synthesis in response to undernutrition.
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PMID:Intestinal brush border membrane structure and function: effect of early postnatal undernutrition. 725 34

The effect of a single oral dose of malathion (1 g/kg body wt.) on the digestive and absorptive functions of the intestinal epithelium has been investigated in rats. The absorption of glucose and glycine was considerably reduced (35%) inpesticide fed animals compared to controls. The activities of brush border sucrase, lactase, alkaline phosphatase, Mg2+-ATPase and lactate dehydrogenase were also significantly depressed in malathion exposed rats, but there was no change in the leucine aminopeptidase levels under these conditions. Mucosal DNA, RNA and protein contents remained unaltered in pesticide toxicity. These results suggest that malathion toxicity induces functional derangements of the intestine.
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PMID:Effect of a single oral dose of malathion on D-glucose and glycine uptake and on brush border enzymes in rat intestine. 744 81

Mucosal surface area, protein, DNA and RNA content, [3H]-thymidine incorporation, total activity of glucosidases, peptidases, phosphatases and transaminases were measured in the duodenum and in the middle and lower parts of the small intestine of the domestic pigeon Columba livia. Mucosal surface area, protein, nucleic acid content and [3H]-thymidine incorporation were significantly higher in the duodenum and in the middle part of the small intestine than in the lower part. Whereas the activities of alkaline phosphatase, sucrase, cellobiase and lactase were significantly higher in the middle part of the small intestine, those of maltase, glucoamylase and leucine aminopeptidase were significantly higher in the lower part. It is concluded that in Columba livia small intestine, regional differences are more pronounced between the middle and the lower parts of the small intestine than between this middle part and the duodenum.
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PMID:Regional differences along the small intestine of the pigeon (Columba livia): histobiochemical evidences. 769 Dec 16

The effect of feeding ethanol daily for 40 days was studied on various brush border enzymes in rat intestine. Brush border alkaline phosphatase (AP), lactase, gamma-glutamyltranspeptidase (gamma-GTP), p-nitrophenyl (PNP)-beta-D-galactosidase (P < 0.01) and sucrase (P < 0.001) were significantly enhanced while leucine aminopeptidase and PNP-beta-D-glucosidase activities were unaltered in ethanol fed rats compared to the controls. Kinetic studies revealed that an increase in Vmax together with a decrease in affinity in case of gamma-GTP and an increase in Vmax for AP and sucrase were responsible for the observed stimulation of enzyme activities in ethanol administered rats. Significant changes in enzyme activities were observed in different populations of enterocytes along the crypt-villus unit in the ethanol fed animals. These observations suggest that ethanol feeding modifies the brush border enzymes in rat intestine but the underlying mechanisms seem to be distinct in differentiating enterocytes.
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PMID:Expression of brush border enzymes in ethanol fed rat intestine. 782 69


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