Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a study of changes in digestive enzymes after massive intestinal resection and the mechanisms by which such changes occur, rats were sacrified 4 wk after removal of the proximal two-thirds of the small intestine. Alterations in the mucosal levels of sucrase, enterokinase, and dipeptide hydrolase (L-leucyl-L-alanine substrate) were examined in the light of associated changes in protein. DNA and wet mucosal weight, measured in standardized gut segments from various regions of intestine. Metabolic studies showed that normal growth patterns were reestablished after the operation but significant elevations in stool weight and fecal nitrogen occurred in the second postoperative week, falling towards normal by the 4th wk. In standard gut segments wet weight of mucosa, protein, and DNA rose, especially in distal segments, DNA increasing disproportionately. Mucosal levels of the proximally distributed and membrane-bound enzymes, sucrase and enterokinase, showed similar patterns of change: when enzyme activity was expressed in terms of the total per segment, proximally there were considerable increases in both enzymes, but, expressed in terms of specific activity, that of sucrase fell and that of enterokinase was unaltered. By contrast, the largely soluble and more distally distributed dipeptide hydrolase increased more in distal segments and the increases in total activity were accompanied by lesser increases in specific activity. However, in spite of increases in total activity, enzyme activity per milligram DNA fell by over 50% in postanastomotic segments. Subcellular distribution studies showed no change in the percentage of the total activity which was membrane-bound and zymograms confirmed that no new dipeptide hydrolase had appeared after resection. It is concluded that increases in the segmental totals of various enzymes seen after resection are achieved by disproportinate increases in the number of mucosal cells per segment and that the greatest change in a particular enzyme occurs in the region where the enzyme is normally found in highest concentration.
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PMID:Changes in sucrase, enterokinase, and peptide hydrolase after intestinal resection. The association of cellular hyperplasia and adaptation. 469 57

Three enzymes of intestinal origin-enterokinase, alkaline phosphatase, and sucrase-were released into the perfused small intestinal lumen of the rat upon intravenous injection of the gastrointestinal hormone cholecystokinin-pancreozymin (CCK-PZ). The presence of bile in the perfusion fluid greatly augmented this release. The results suggest that a combined mechanism of enzyme liberation due to direct hormonal stimulation of the gut wall and further solubilization of released intestinal enzymes by bile may be responsible for the appearance of these enzymes in the gut lumen.
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PMID:Hormone-elicited enzyme release by the small intestinal wall. 504 Aug 34

Specific and total activities of the disaccharidases, sucrase, maltase, and lactase are increased in mucosa of the small intestine of the streptozotocin diabetic rat. Because disaccharidases are essential for terminal digestion of carbohydrate, and disaccharidase deficiency is a common clinical problem, understanding the mechanisms regulating disaccharidase activity is important. In normal animals, disaccharidase activities are determined by route of feeding and are decreased by parenteral feeding. The indirect exocrine, endocrine, neurocrine, and paracrine functions of the gastrointestinal tract that are dependent on feeding via the gut are greatly decreased in parenteral as compared with enteral feeding. Hormone secretion by the gut and the pattern of response after feeding may be abnormal in diabetes and might be regulatory for disaccharidases. We tested the hypothesis that the elevated intestinal disaccharidases in diabetes are dependent on enteral feeding. Streptozotocin-injected rats (diabetics) and vehicle-injected rats (controls) were fed rat chow ad libitum for 4 days. A subset of control and diabetic animals was then killed to determine disaccharidase activity of the jejunum at the start of pair-feeding the elemental diet. The remaining animals were fed 60 cal/day of glucose, amino acid (Travasol), and electrolyte solution either intragastrically or intravenously for 4 days. Specific and total activities of disaccharidases were greater in diabetics than in controls under all feeding conditions. In controls, the pattern of activity of disaccharidase specific activity was initial greater than intragastric greater than intravenous. In diabetics, disaccharidase specific activities did not differ among groups. In both controls and diabetics, mean mucosal mass was highest initially; intermediate with intragastric feeding; and lowest with intravenous feeding. In both controls and diabetics, total disaccharidases decreased from initial to intragastric to intravenous. We conclude: (1) disaccharidase specific activity in controls is sensitive to feeding route and nature of diet, but is nearly independent of these factors in diabetics; (2) total disaccharidase activities respond to feeding stimuli in parallel with changes in mucosal mass in both controls and diabetics; and (3) the lack of feeding effect on the elevated specific activities of disaccharidases in diabetes suggests that this elevation is a response to the diabetic state and is independent of enteral factors such as luminal nutrition and gastrointestinal hormones.
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PMID:Elevated intestinal disaccharidase activity in the streptozotocin-diabetic rat is independent of enteral feeding. 640 7

The longitudinal distribution of the main brush border membrane hydrolases was studied in six entire human small intestine, one of which was found to be lactase-deficient. Sucrase and lactase activities were found to be highest in the jejunum, whereas glucoamylase activity rose steadily and reached its highest activity near the ileocecal valve. Maltase activity distribution was intermediate between that of sucrase and of glucoamylase. Neutral aminopeptidase, acid aminopeptidase and dipeptidyl peptidase IV activities tended to increase toward the end of the small bowel, the latter two activities rising more than the first one. Furthermore, the protein compositions of the brush border membrane in the jejunum and in the ileum were compared after electrophoresis on polyacrylamide gels and crossed-immunoelectrophoresis; protein patterns were found to be similar along the gut, and enzyme-specific activities varied in parallel with the amounts of their corresponding proteins. In the lactase-deficient intestine, the protein band corresponding to lactase was not visible. Maximal digestive capacity was thus localized in the jejunum only for disaccharides, and in the ileum for the more complex substrates, oligosaccharides, and peptides; this finding suggests that the ileum may play a greater role in their terminal digestion than is usually admitted.
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PMID:Longitudinal study of the human intestinal brush border membrane proteins. Distribution of the main disaccharidases and peptidases. 641 75

The effect of dexamethasone (DX) on the prenatal maturation of rat intestinal brush border enzymes was studied in organ culture. Jejunal segments were explanted daily from day 17 of gestation until birth, as well as at different postnatal stages until day 6; they were cultured for 48 h with or without DX (8 X 10(-8) M). Enzymatic activities were analyzed on brush border membranes purified from cultured intestines and were compared with values from uncultured specimens. The results showed that DX elicited (a) a precocious induction of sucrase activity in the jejunum explanted from 19 days of gestation onward, reaching a peak value when taken at birth; (b) a stimulation of maltase activity in the segments explanted as soon as day 18, leading to maximal values when taken at day 20, the stage at which the stimulated activity reached a 6.5-fold increase over the baseline activity; and (c) an increase of lactase activity comparable to that occurring in utero. As opposed to this, DX has no specific action on alkaline phosphatase and aminopeptidase activities. The present data indicate that glucocorticoids directly and specifically influence the prenatal maturation of some brush border enzymes in the mammalian gut.
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PMID:Control of brush border enzymes by dexamethasone in the fetal rat intestine cultured in vitro. 682 Nov 11

The response of the intestinal mucosa to Adriamycin (ADR) was studied in the duodenum, jejunum, and ileum of 25-day-old rats. A single injection of ADR resulted in decreases in mucosal DNA per centimeter of length and in sucrase activity, which were proportional to the doses given (2, 5, and 8 mg/kg). ADR at 2 mg/kg had no significant effect on body weight, gut length, epithelial structure, or mucosal protein content per unit length. The morphological modifications occurred mostly in the proximal intestine and consisted of villous atrophy and degenerative changes of villus and crypt cells. A single dose of 5 mg ADR/kg acutely affected the gut. At 48 and 96 h the changes were characterized by marked decreases in mucosal weight, DNA per centimeter, sucrase activity, and villous shortening. At 144 h, the ADR-treated intestine entered a highly proliferative state and showed increased villous height, mucosal weight, and DNA per centimeter. Although villous hyperplasia was observed at 144 and 192 h, the mucosal weight and DNA concentrations did not exceed the corresponding levels in the control. During the period of active epithelial proliferation, sucrase activity remained depressed. We conclude that in the growing rat: (a) the acute intestinal injury of ADR is short-lived, dose dependent, and predominates in the proximal small intestine; (b) the enteric mucosa reacts to cytotoxic injury by excessive proliferation of immature enterocytes; and (c) the hyperplastic response to ADR is confined to the mucosal epithelium.
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PMID:Adaptive response of growing rat small intestine to acute Adriamycin injury. 688 38

1. The levels of the brush-border enzymes sucrase (sucrose glucohydrolase, EC 3.2.1.48), isomaltase (oligo-1,6-glucosidase, EC 3.2.1.10), maltases 2 and 3 (glucoamylase, EC 3.2.1.3), lactase (beta-galactosidase, EC 3.2.1.23) and trehalase (EC 3.2.1.28) and adsorbed pancreatic alpha-amylase (EC 3.2.1.1) have been measured at twenty-one positions along the small intestines of eighty-four pigs of different ages ranging from 3 weeks to 4.5 years. The state of dilation of the intestine at the sampling points was noted. 2. The levels of sucrase and isomaltase increased with age throughout the age-range studied. Trehalase and the glucoamylases increased with age up to 200--300 d of age. Lactase decreased with age over the whole age range. 3. For the pigs above 10 weeks of age, the distribution pattern of the brush-border enzymes along the intestine did not change with age. Each enzyme had a characteristic distribution curve, with low values at the proximal and distal ends and a peak which was proximal in the instance of lactase and trehalase and approximately mid-way along the gut with sucrase, isomaltase and the glucoamylases. 4. The pattern of distribution of the brush-border enzymes altered with age in the piglets, but approached the adult pattern by 8 weeks. 5. Piglets weaned at 3 weeks had higher levels of sucrase, isomaltase and glucoamylases at 5 weeks than piglets left on the sow. At 8 weeks of age the piglets weaned at 3 weeks still had higher sucrase and isomaltase levels than those on the sow. 6. There was a very close correlation between the sucrase and isomaltase levels, and between the maltase 2 and maltase 3 levels in all the samples, and a fairly close correlation between all these four enzymes. 7. The level of alpha-amylase increased with age but showed no regular distribution pattern, its irregular fluctuations being related to the presence or absence of dilation of the intestine at the time of slaughter rather than to the position along the intestine.
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PMID:The level of distribution of carbohydrases in the small intestine mucosa of pigs from 3 weeks of age to maturity. 696 56

The development of the duodenal, jejunal, and ileal mucosal mass was studied in five groups of rats killed at different ages during growth. After sacrifice, the small bowel was removed from the pylorus through the ileocecal valve, measured and divided into three equal segments (A, B, C). Gut weight, mucosal weight, DNA, protein, and sucrase activity were determined in each segment. For each segment, results of all mucosal mass parameters expressed per centimeter of gut length markedly increased during weaning (15-30 days), and at 40 days of age they were similar to those obtained in adult animals. A proximal to distal gradient of gut weight was present at birth and increased during lactation. However, the proximodistal gradients of mucosal weight and mucosal DNA per centimeter of length remained constant in all groups studied. The intestinal gradient of sucrase activity was absent at birth and in lactating rats (17 days), but was similar in rats of 30, 40, and 100 days of age. It was concluded that mucosal hyperplasia which occurs in rats at weaning equally develops in the proximal, mid, and distal small bowel.
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PMID:Postnatal proximodistal development of the small bowel mucosal mass in growing rats. 728 93

The in vitro and in vivo production of hydrogen gas (H2) from various carbohydrates or proteins has been examined in normal rats and in rats infected with the nematode Nippostrongylus brasiliensis. Normal rat fecal homogenates were capable of producing H2 in vitro from glucose, sucrose, xylose, lactulose, bovine serum albumin, or casein hydrolysate. Direct injection of glucose, sucrose, xylose, lactulose, bovine serum albumin, or casein hydrolysate into the cecum of normal rats resulted in approximately twice as much H2 production in vivo than when these same carbohydrates or proteins were administered to the normal rats by gavage. Partial small intestinal villous atrophy was produced by infecting rats with the nematode N. brasiliensis. Impaired small intestinal cell function and evidence of malabsorption in the nematode-infected rats included: (a) decreased activity of intestinal cell lactase (-43%), sucrase (-33%), and alkaline phosphatase (-46%); (b) decreased gut sac uptake of 3-O-(methyl-3H]-D-glucose (-21%) or 1-[carboxyl-14C]-aminocyclopentane-1-carboxylic acid (-28%); and (c) increased (+ 64%-561%) 14CO2 production after D-[U-14C]xylose administration. These rats produced approximately twice as much H2 after gavage administration of glucose, sucrose, xylose, bovine serum albumin, or casein hydrolysate compared with normal rats. The present study suggests that H2 analysis may be useful in the evaluation of small intestinal malabsorption states in rats.
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PMID:Use of hydrogen gas (H2) analysis to assess intestinal absorption. Studies in normal rats and in rats infected with the nematode, Nippostrongylus brasiliensis. 728 87

The effect of vitamin C deficiency on the digestive and absorptive functions of the gut has been investigated in guinea pigs. The absorption of D-glucose was significantly elevated, but that of L-leucine, L-alanine and L-lysine considerably depressed in the intestine of scorbutic guinea pigs compared to controls. The intestinal transport of vitamin B12 was also diminished. Activities of sucrase and alkaline phosphatase on the brush border were enhanced, but that of leucine aminopeptidase markedly reduced in scorbutic animals compared to controls. Maltase activity was unaffected in vitamin C deficient animals. Chemical analysis of the brush borders isolated from scorbutic animals revealed a considerable decrease in membrane protein, total lipids, phospholipids, and free cholesterol contents compared to control animals. In vivo 2-(14)C-acetate incorporation into membrane lipids suggested that the observed decrease in lipid components of the scorbutic membranes is due to reduced synthesis. Administration of ascorbic acid to scorbutic animals ameliorated the intestinal aberrations observed in scurvy.
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PMID:Effect of vitamin C deficiency in guinea pigs on intestinal functions and chemical composition of brush border membrane. 730 86


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