Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although TPN is used frequently in young infants, little information is available regarding its effect on postnatal development of the gut. The effect of total parenteral nutrition (TPN) and intragastric (IG) alimentation on ontogeny of the small intestine was examined in infant rabbits starting at 10-12 days. Animals were killed at 17-19 days. Body weight, organ weight and weight of segments of proximal, mid and distal small intestine were measured. Intestinal mucosa was scraped, weighed and homogenized for estimation of protein, DNA and disaccharidases. Na+ transport was examined in short-circuited jejunum. Weight gain was similar in controls, sham-treated and TPN animals, but was significantly reduced in IG animals. TPN induced precocious development of sucrase and maltase activity and glucose-stimulated Na+ transport, despite causing a significant decrease in mucosal weight and DNA and pancreatic amylase. IG alimentation also induced precocious development of sucrase, maltase and glucose-stimulated Na+ transport. Thus TPN, despite producing mucosal atrophy and decreased pancreatic exocrine development, stimulates accelerated postnatal maturation of the small intestine.
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PMID:Effects of parenteral and enteral nutrition on postnatal development of the small intestine and pancreas in the rabbit. 310 3

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 (GLN) is an important fuel and epidermal growth factor (EGF) is a potent mitogen for intestinal mucosa cells. GLN-enriched parenteral nutrition was administered to male Wistar rats, and subcutaneous injections of EGF were given for 3, 6, and 7 days. Control animals were fed a non-GLN-containing solution. Other groups of animals received GLN or EGF alone. Mucosal samples were obtained from the jejunum, ileum, and colon for measurement of weight, DNA, protein, and mucosal thickness. Disaccharidase activity was measured in the jejunum. After 3 days, only animals that received both GLN and EGF had a significant increase in small-bowel mucosal protein and thickness relative to controls. A similar pattern was observed in the colon, where animals that received both agents had a greater mucosal thickness, DNA, and protein content than controls. At 7 days, animals that received EGF or GLN had greater nitrogen retention. In addition, animals that were treated with EGF had elevated sucrase and maltase activity compared with GLN-fed animals at this time. Animals treated with GLN and EGF tended to have increased sucrase activity relative to controls. GLN feeding was associated with increased mucosal DNA and protein contents throughout the intestine for the combined series. EGF increased mucosal DNA and protein in the small intestine but not in the colon. The effect of EGF on the protein content of the small-bowel mucosa was dose dependent. The effects of GLN and EGF on the small bowel and colonic mucosa were additive. These studies suggest that specific nutrients and hormones may be used in combination to decrease the mucosal atrophy that commonly occurs after gut disuse or disease.
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PMID:Combined effects of glutamine and epidermal growth factor on the rat intestine. 313 28

The role of thyroxine and insulin in the regulation of proliferation and differentiation of the immature duodenal epithelium of the fetal mouse was investigated using an organ culture method with a serum-free medium. Thyroxine (10 nM) stimulates specifically the activity of maltase. Insulin (125 mU/mL) remains without effect on the maturation of all hydrolytic functions studied. Each hormone significantly increases the percentages of brush border enzyme activities liberated in the medium and reduces the amount of glucose released in the medium. In the presence of dexamethasone (76 nM) the effect of thyroxine on maltase activity is still observed. Finally, thyroxine and insulin do not modify the labelling index in the duodenal crypts of the explants in the presence or absence of dexamethasone. These findings indicate that thyroxine and insulin can act directly on the development of the fetal mouse duodenum at the end of gestation. Nevertheless, their implication in prenatal development of the gut functions appears to be of minor importance.
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PMID:Role of thyroxine and insulin on the development of the fetal mouse duodenum in organ culture. 353 89

We previously have shown that aging alters the expression of several intestinal enzymes during cell migration from the crypt base to the villus tip. The activities of many mucosal enzymes are dramatically altered by starvation and refeeding. We compared the effects of starvation and refeeding on the activities of selected intestinal enzymes in young and aging Fischer 344 rats. Gut mass fell during starvation and rose during refeeding to a similar extent in both groups. Sucrase and maltase specific activities in control aging rats were lower than in young controls and, during starvation, enzyme activities declined at approximately similar rates in both groups. Total duodenal enzyme activities fell by about two-thirds in young animals and by greater than 80% in aged animals. Alkaline phosphatase and adenosine deaminase activities also were lower in aging than young animals. During refeeding, enzyme activities rose more in aging rats than in the young. In fact, the specific activities of sucrase and maltase in aging rats refed for 1 day exceeded the values found in fed aging controls. The adaptive responses of duodenal enzymes exceeded those in the jejunum. In conclusion, the aging intestine responds appropriately to starvation and refeeding. However, the fluctuations in brush-border enzyme activities are much greater in aging than in young rats. Such alterations may be an important influence of aging on gut differentiation and might have an adverse impact upon nutritional maintenance in aging animals.
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PMID:Adaptive changes of intestinal enzymes to nutritional intake in the aging rat. 359 66

Intestinal adaptation has been studied in rats with pancreatic atrophy induced by feeding a copper-deficient diet and penicillamine and in rats with carbohydrate maldigestion induced by feeding of an alpha-glucosidase inhibitor (acarbose). Pancreatic atrophy led to a significant increase of weight, protein, and DNA content as well as specific activities and total amounts of the enzymes sucrase and maltase in the distal but not in the proximal part of the small intestine. Plasma levels of CCK and GIP were significantly higher in rats with pancreatic atrophy, whereas plasma levels of gastrin and insulin were lower. Tissue concentrations of gastrin in the antrum and GIP in duodenum and jejunum were unchanged. Duodenal CCK and jejunal substance P, somatostatin, and VIP and ileal substance P and somatostatin were significantly decreased in rats with acinar atrophy. Glucosidase inhibition by acarbose feeding led to weight increase of the small intestine and cecum. This was more marked when acarbose was fed together with a fiber-free diet. Under these conditions the protein and DNA content also increased significantly in both gut segments and maltase and sucrase content predominantly in the distal part. Insulin plasma concentration decreased significantly in the acarbose-fed groups, whereas GIP, gastrin, and CCK plasma concentrations remained unchanged. After fiber-rich diet tissue concentrations of gastrin in the antrum and insulin in the pancreas were significantly higher and GIP concentrations in the duodenum and jejunum significantly lower than after fiber-free diet. Acarbose increased the pancreatic insulin concentration only in the fiber-free group and did not influence gastrin and GIP concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adaptation of the small intestine to induced maldigestion in rats. Experimental pancreatic atrophy and acarbose feeding. 389 54

A simple and reproducible method for cultivation of fetal chicken small intestine is presented. The culture was performed in a defined medium without serum. Duodena were excised from embryos at the 14th day of fetal development and cut in small segments that were maintained in culture until day 16. It could be shown that the morphology of cultured intestine resembles that of noncultured gut of corresponding age as judged by light microscopy. The increase in activity of sucrase and maltase in cultured explants is comparable with that of intestine in ovo, whereas that of alkaline phosphatase is lower than under in vivo conditions. Hormones (thyroxine, dexamethasone) influence the enzymic pattern of fetal intestine in a known manner. Therefore, the method permits maintenance of fetal intestine in tissue culture for 2 days, a period sufficient for investigation of maturation processes of intestinal mucosa.
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PMID:Chicken fetal intestine in tissue culture. 402 13

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 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

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


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