Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatostatin is a widely distributed hormone localized in the central nervous system, pancreas and gastrointestinal tract. We have investigated the possible influence of somatostatin and a synthetic analogue, (D-Trp8,D-Cys14)-somatostatin, on the intestinal absorption 'in vivo' of D(+)-glucose and D(+)-galactose and also the effect on disaccharidase intestinal activities in hamster. Somatostatin, or its analogue, (12 micrograms/100 g body wt) was administered intraperitoneally 4 or 14 h prior to experiments. The results are compared to control animals. Animals treated with somatostatin and the synthetic analogue showed that there were no significant difference from control animals with respect to intestinal absorption of carbohydrates. Somatostatin produced inhibition of brush-border lactase activity in females only, whereas brush-border sucrase was increased 14 h after treatment in males and females, and brush-border maltase was inhibited in females only 4 h after hormone administration.
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PMID:Somatostatin and its analogue (D-Trp8,D-Cys14)-somatostatin do not modify intestinal absorption in vivo of carbohydrates in hamster intestine, but they do modify some disaccharidases. 251 89

The influence of somatostatin injection on intestinal disaccharidase and alkaline phosphatase activity in rat and chick was investigated. Disaccharidase and alkaline phosphatase activities of rat and chick homogenates were not modified. In rat the activities of mucosal brush-border maltase and sucrase were significantly increased. In chick brush-border a significant increase of duodenal mucosal activity and duodenal and jejunal sucrase activity is observed.
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PMID:Effect of somatostatin on small intestine enzyme activities in rat and chick. 285 90

Sleep patterns were continuously recorded in the genetically obese Zucker rat. Under normal feeding conditions, Zucker rats showed large amounts of slow-wave sleep (SWS) and normal amounts of pardoxical sleep (PS). In addition, both SWS and PS were equally distributed throughout the nychthemeron. When acarbose (an alpha-glucosidase inhibitor that slows absorption of glucose, reduces plasma insulin, and increases plasma somatostatin) was added to food pellets, the daily duration of SWS was markedly decreased, whereas PS was significantly increased. These results clearly show that sleep in the Zucker rat differs substantially from that classically observed in normal lean rats. In addition, they suggest that anomalies of insulin and somatostatin production and/or levels may cause the sleep disturbances observed in Zucker rats.
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PMID:Sleep patterns in the genetically obese Zucker rat: effect of acarbose treatment. 291 22

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

1. Analytical subcellular fractionation techniques have been applied to endoscopic human rectal biopsies to study the localization of enteroglucagon, somatostatin, vasoactive intestinal peptide and the properties of the principal subcellular organelles. 2. The peptide hormones, detected by radioimmunoassay, showed particulate localizations with single peaks in the density gradients for enteroglucagon (modal density 1.25) and somatostatin (modal density 1.23). Vasoactive intestinal peptide showed a less discrete localization but demonstrated a major peak (modal density, 1.17) with a small subsidiary peak (modal density 1.24). 3. The following organelles, characterized by their marker enzymes, were located in the density gradients; plasma membrane (5'-nucleotidase), mitochondria (malate dehydrogenase), peroxisomes (catalase), lysosomes (beta-N-acetyl-D-glucosaminidase), endoplasmic reticulum (neutral alpha-D-glucosidase) and cytosol (lactate dehydrogenase). 4. This technique can be used to investigate disease of the human rectum at a subcellular level.
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PMID:Subcellular fractionation studies of human rectal mucosa: localization of the mucosal peptide hormones. 610 76

The effect of somatostatin on mucosal DNA, protein and brush border enzymes was studied in organ cultured rabbit jejunum and ileum. Compared to control cultures, somatostatin reduced the biopsy DNA and protein content in parallel in the jejunum, but was ineffective in the ileum. This was probably due to a direct growth inhibition, since DNA and brush border enzyme activity from desquamated cells in the postculture medium were unaffected. In addition, a direct inhibition of jejunal villous cell differentiation by somatostatin was reflected in a significant decrease of sucrase, maltase and alkaline phosphatase activity. In the ileum, only the specific activity of alkaline phosphatase was reduced. The key enzyme of cholesterol synthesis, HMG-CoA-reductase, was measured as an intracellular enzyme control and was not influenced by the hormone. The high somatostatin concentrations necessary to achieve the effects are not an artefact of hormone degradation during culture, as shown by radioimmunoassay, and suggest a local or "paracrine" rather than systemic, inhibitory action of somatostatin on intestinal growth and differentiation.
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PMID:Inhibitory effects of somatostatin on growth and differentiation in cultured intestinal mucosa. 614 52

Analytical subcellular fractionation techniques using metrizamide density gradients have been used to investigate the properties of the gut hormone storage granules and the principal organelles from homogenates of normal human jejunal mucosa obtained by peroral mucosal biopsy. The individual hormones, detected by radioimmunoassay, each showed single discrete peaks in the density gradient experiments indicating localisation to single granules each with characteristic modal densities. Thus motilin showed a modal density of 1.15, gastrin 1.16, gastric inhibitory polypeptide (GIP) 1.17, enteroglucagon 1.18 and somatostatin and vasoactive intestinal peptide (VIP) 1.10 g/ml. The following organelles, characterised by their marker enzymes were located in the density gradients; plasma membrane (5'-nucleotidase) brush border (alpha-glucosidase, pH 6.0) mitochondria (particulate malate dehydrogenase), peroxisomes (catalase), lysosomes (N-acetyl-beta-glucosaminidase), endoplasmic reticulum (alpha-glucosidase, pH 8.0), cytosol (lactate dehydrogenase). These studies provide biochemical evidence of the distinct nature of the individual gut hormone storage granules and provide a basis for studying dynamic changes in the granules in response to physiological stimuli and pathological processes.
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PMID:Characterisation of gut hormone storage granules from normal human jejunum using metrizamide density gradients. 730 92

Thirty-eight second parity sows were either immunized (IMM) against somatostatin (SRIF) and/or injected with growth hormone-releasing factor (GRF) during gestation. Treatment effects on pancreatic, gastric and duodenal development as well as on digestive enzyme activity of piglets at birth (before suckling) or at 24 h postpartum were investigated. Birth weights of piglets were similar across treatments (p > 0.1). Weight, DNA, RNA, total protein content and enzyme activity for all three organs increased between birth and 24 h postpartum (p < 0.01), except for pancreatic RNA and chymotrypsin which decreased (p < 0.01), and protein content of the pancreas which was unaltered (p > 0.1). Gastric RNA, pancreatic weight:DNA, RNA:DNA and amylase:DNA ratios were increased in 1-day-old piglets from SRIF-IMM sows (p < or = 0.05). GRF only had significant effects (p < 0.05) on the maltase:DNA ratio, which it decreased. Yet, there were tendencies (p < 0.1) for duodenal weight, DNA and total protein content to be increased in piglets from GRF-injected dams. It is therefore apparent that major developmental changes of the pancreas, stomach and duodenum of piglets take place during the first 24 h postpartum. Injections of GRF and/or immunization against SRIF during gestation in swine also have several effects on digestive enzyme activity of neonatal pigs. Yet, the physiological implications of these early changes are not clear at the present time.
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PMID:Digestive enzyme development in newborn piglets born of sows immunized against somatostatin and/or receiving growth hormone-releasing factor during gestation. 750 40

The aim of this study was to determine the effects of a model of intestinal extrinsic denervation on mucosal structure and function. Six dogs underwent in situ neural isolation of the jejunoileum (Group 2); six other dogs served as operated controls (Group 1), and five nonoperated dogs were naive controls (Group 3). Thirty-centimeter segments of proximal jejunum and distal ileum were excised before (time zero) and at 2 weeks and 8 weeks postoperatively in Groups 1 and 2, while similar regions were removed at time zero in Group 3. Tissues were analyzed for morphology with quantitative morphometry, mucosal disaccharidase activities (sucrase, maltase, and lactase), and tissue content of selected regulatory peptides in transmural, mucosa/submucosa, and muscularis regions. In situ neural isolation had no significant or consistent effects on morphology/morphometry or on mucosal disaccharidase activities. Tissue content of neuropeptide Y decreased markedly (P < 0.002) in all layers of the jejunal and ileal walls, but tissue content of vasoactive inhibitory polypeptide, substance P, cholecystokinin, neurotensin, met-enkephalin, neurokinin A, somatostatin, and calcitonin gene-related peptide demonstrated only minor changes. The physiologic effects of intestinal transplantation (extrinsic denervation and disruption of intrinsic, enteric neural continuity, and lymphatic drainage) have little effect on morphology, mucosal disaccharidase activity, and tissue content of most regulatory peptides. How these minor alterations might affect enteric function, however, needs to be investigated.
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PMID:Neural isolation of the jejunoileum. Effect on tissue morphometry, mucosal disaccharidase activity, and tissue peptide content. 865 18

Glucose homeostasis is maintained by a balance between the release and action of insulin, and the counterregulatory responses mediated principally by glucagon, catecholamines, growth hormone and cortisol. Hence, the effects of a drug on glucose metabolism may be mediated by any of these agents singly or in combination. Host factors, such as inherent glucoregulatory mechanisms, concurrent diseases, organ function and concomitant medications also increase the risk of drug-induced disturbances of glucose homeostasis in susceptible individuals. By far the most important agents causing hypoglycaemia are insulin and the sulphonylureas. Alcohol (ethanol), over-zealous glycaemic control, hypoglycaemic unawareness, detective counterregulation especially in insulin-dependent diabetes mellitus (IDDM), and renal and liver impairment are all important predisposing factors. Although antihyperglycaemic agents such as metformin and alpha-glucosidase inhibitors do not cause hypoglycaemia alone, they may enhance the hypoglycaemic effects of potent hypoglycaemic agents such as insulin and sulphonylureas. On the other hand, the potential hypoglycaemic effects of ACE inhibitors, alpha-blockers, lipid-lowering agents and recombinant human insulin-like growth factor demonstrated in experimental settings, are of potential therapeutic interest. Iatrogenic hypoglycaemia and intensive insulin treatment are associated with hypoglycaemic unawareness which may be obviated by meticulous avoidance of hypoglycaemia. Effective patient education remains an important preventive measure. Oral glucose is used to treat mild hypoglycaemic episodes while more severe episodes are treated by intravenous glucose or glucagon. Nasal glucagon and theophylline are other experimental measures to improve recovery from hypoglycaemia. In refractory hypoglycaemia due to hyperinsulinaemia such as during sulphonylurea overdosage or quinine treatment, the long-acting somatostatin, octreotide, may suppress insulin release and restore euglycaemia. Diuretics, beta-blockers, sympathomimetics, corticosteroids and sex hormones are commonly prescribed drugs which may have adverse effects on carbohydrate metabolism especially in patients with diabetes mellitus or those who are at risk of developing glucose intolerance. Pentamidine was frequently associated with dysglycaemia due to its pancreatic beta-cell cytotoxic effects but is now used less often to treat Pneumocystis carinii pneumonia in immunosuppressed patients. Despite the large number of anecdotal reports of drug-induced disturbances of glucose metabolism, many of the so-called adverse drug reactions were either idiosyncratic or coincidental. Nevertheless, they emphasise the complex nature of glucose homeostasis and its potential interactions with drugs, host factors and disease states. An understanding of these relationships may allow more critical interpretation of these clinical observations, better prediction of drug induced adverse effects on carbohydrate metabolism and the implementation of more rational therapy. Hence, the hypoglycaemic effects of a drug may be turned to a therapeutic advantage in patients with glucose intolerance. Similarly, the hyperglycaemic effect of a drug may help to treat refractory hypoglycaemia.
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PMID:Drug-induced disorders of glucose metabolism. Mechanisms and management. 888 64


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