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:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neurotensin has many actions on digestive tract motility and secretion and stimulates pancreatic growth. We examined effects of chronic administration of neurotensin on growth of small intestine and colon. Four groups of 10 rats were injected with saline or neurotensin (33, 100, or 300 micrograms/kg) every 8 h for 5 days. The small intestine was divided into four segments of equal length, weighed, and assayed for DNA, protein, and brush-border digestive enzymes. The colon was weighed and assayed for DNA and protein. Neurotensin caused dose-related increases in growth of small intestine; at the highest dose, similar increases in weight (12-20%), DNA (23-35%), and protein content (33-39%) occurred in each segment of small intestine. Maltase, sucrase, and leucine aminopeptidase (but not lactase) contents were also significantly increased after neurotensin, but the largest effects were seen in the proximal small intestine. Neurotensin had no effect on weight, DNA, or protein content of the colon. These results suggest a role for neurotensin in regulating growth of small intestine.
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PMID:Neurotensin stimulates growth of small intestine in rats. 320 74

The intestinal absorptive and digestive functions using the brush border membrane (BBM) vesicles were evaluated in guinea pigs receiving cholesterol-supplemented diet for 12 weeks. The Na+-gradient-dependent transport of D-glucose (p less than 0.001), L-alanine and L-phenylalanine (p less than 0.01) was decreased significantly the BBM of cholesterol-fed animals. The maximal velocity (Vmax) value of the sucrase and leucine aminopeptidase was decreased without any change in the affinity constant (Km) value, demonstrating that the enzyme contents were reduced in response to cholesterol-rich diet. However, both the Km and Vmax values of the alkaline phosphatase decreased markedly, suggesting that a new enzyme of increased substrate affinity had been formed due to intestinal adaptation of cholesterol load in diet. The present study demonstrated that cholesterol feeding caused a significant alteration in nutrients absorption, membrane enzymes and chemical composition of the small intestine.
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PMID:Enzymatic and transport studies in cholesterol-fed guinea pigs using intestinal brush border membrane vesicles. 352 33

The long-term effect of lithium treatment on the digestive and absorptive function has been investigated in male albino rats. The uptake of D-glucose, amino acids and activities of cellular and brush border enzymes were evaluated after every 3 months. Significantly increased uptake was observed in 6-month lithium-treated rats. The absorptive capacity (Vmax) for D-glucose increased significantly without alteration in the Michaelis constant. Activities of cellular, brush border membrane disaccharidase, leucine aminopeptidase and Na+,K+-ATPase enzymes were significantly augmented in 6-month lithium-treated animals. The elevation in sucrase activity may be due to induction of enzyme since only Vmax was increased in lithium-treated animals. The present biochemical alterations suggest that long-term lithium ingestion stimulates the small bowel digestive and absorptive functions.
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PMID:Effect of lithium ingestion on digestive and absorptive function of rat intestine. 356 79

The present study was undertaken to provide further evidence for mechanisms proposed for the toxicity of ingested winged bean lectin in animals: to determine its effect on activities of some hydrolases localized in the brush border membrane of the small intestine. An adaptive increase in sucrase activity of rats given a high-sucrose diet (HSD) was restrained by the addition to HSD of a lectin fraction (WBLF) isolated from raw winged beans but not by that of heated WBLF or soybean trypsin inhibitor. Restraining effects of WBLF added to HSD on time-course changes in activities of sucrase, alkaline phosphatase and leucine aminopeptidase of rats after giving HSD were similar to those of concanavalin A, which had been observed in the previous study. These results substantiate that the mechanism of the toxicity of ingested winged bean lectin involves its binding to the luminal surface of the small intestine and in turn disturbing the functional formation of the brush border membrane.
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PMID:Effect of ingested winged bean lectin on gastrointestinal function in the rat. 371 4

The apical membranes of rabbit gallbladder epithelial cells were isolated by treating the homogenate with Ca2+ or Mg2+ and centrifuging the suspension in Percoll gradient. In this way brush-border membranes were obtained with enrichment factors ranging between 10 and 20 and yields of 15-30%. A second method is described with which membranes were isolated, without any preliminary treatment, first by differential centrifugation, then with Percoll gradient; the final membrane enrichment was over 15, however the yield was very low (3%). Many possible enzymatic markers of the apical plasma membrane were investigated: L-gamma-glutamyltransferase, alkaline phosphatase, leucine aminopeptidase, sucrase. The first appears to be that of choice. Apical membrane fraction could be also evidenced by autofluorescence or by labeling with Lotus tetragonolobus lectin. Preliminary experiments showed that apical plasma membranes isolated in this way form vesicles.
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PMID:Isolation of apical plasma membrane in rabbit gallbladder epithelium by Percoll density gradient centrifugation. 381 91

To determine whether zinc has a specific role on intestinal growth and function, three groups of male weanling Sprague-Dawley rats were fed a semipurified zinc-deficient diet: ad libitum fed group received powdered diet and water containing 25 ppm of zinc; force fed (ZN, ZD) groups were fed identical amounts of diet to the ad libitum fed group by intragastric infusion three times per day. The diets were aqueous suspensions made with either deionized water (ZD) or water containing 25 ppm of zinc (ZN), and additional drinking water with (ZN) or without zinc (ZD) was offered ad libitum. Rats were sacrificed after 8 days of feeding. The ZD group showed growth arrest, perioral and periorbital dermal lesions, and abdominal distention within 8 days of feeding. Mucosal DNA, protein, sucrase, maltase, lactase, leucine aminopeptidase, and alkaline phosphatase were significantly decreased in the ZD group, whereas intestinal length, weight, and mucosal weight were unaltered. These results suggest that short-term isolated zinc deficiency impairs growth, digestion, and absorption in the rat small intestine, even in the absence of associated protein calorie malnutrition.
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PMID:Effects of short-term isolated zinc deficiency on intestinal growth and activities of several brush border enzymes in weaning rats. 408 Apr 54

1. A technique is described for the removal of subcellular contaminants from intact rat intestinal brush borders, and for the subsequent separation of a microvillus membrane fraction from a fibrillar residue. 2. Increments in invertase activity, microscopic homogeneity and low nucleic acid content indicate that the microvillus plasma membrane has been extensively purified. Multiple membrane preparations have been shown to be highly reproducible with respect to their invertase specific activity, cholesterol content and phospholipid content. Alkaline phosphatase, leucine aminopeptidase, Mg(2+)- and Ca(2+)-dependent adenosine triphosphatase and seven separate disaccharidases were shown to be predominantly confined to the membrane fraction. 3. The fibrillar fraction has been shown to contain approximately 30% of the total protein of purified brush borders, plus most of the residual nucleic acid contaminant. No evidence was found for the localization of any specific enzyme in this fraction.
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PMID:Rat intestinal microvillus membranes. Purification and biochemical characterization. 429 31

The effect of a single oral dose of endosulfan (5 mg/kg body weight) on the uptake of certain nutrients and brush-border enzymes has been studied in rat intestine. The uptake of glucose and alanine was elevated but that of leucine was decreased in endosulfan-fed rats. There was no change in the uptake of phenylalanine and lysine in insecticide-fed rats. The activities of brush-border sucrase and alkaline phosphatase were considerably increased while the activity of Na+ K+ ATPase was reduced in endosulfan-exposed animals. The leucine aminopeptidase activity was unaffected in pesticide-treated rats. There was a significant decrease in cellular LDH and GOT activities with no change in GPT activity. Neither was there a considerable increase in the cellular glucose-6-phosphatase activity (P less than 0.01) in the pesticide-fed rats. These results suggest that endosulfan toxicity induces certain functional changes in the intestine.
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PMID:Effect of a single oral dose of endosulfan on intestinal uptake of nutrients and on brush-border enzymes in rats. 618 May 24

The effects of medroxyprogesterone acetate (MPA) on the digestive and absorptive functions of the small intestinal epithelium have been investigated in female albino rats. The transport of sodium-dependent glucose was significantly enhanced while sodium-independent transport remained unaltered in drug-treated animals. The uptake of amino-acids was also considerably increased, while Ca++ uptake decreased significantly on administration of the drug at a dose of 35 mg/kg body weight once a week for 1 month. Kinetic studies of glucose transport in the presence of sodium ions revealed that MPA treatment affected the rate of uptake of glucose by elevating Vmax, but the Km value remained the same in treated and untreated animals. The administration of the drug also led to significant augmentation in the activities of the brush border enzymes, disaccharidases, and to an insignificant decrease in alkaline phosphatase. The activities of leucine aminopeptidase did not show any change. The enhancement in sucrase activity might be due to induction of the enzyme because only Vmax was elevated in treated animals. As concerns cellular enzymes, lactate dehydrogenase activity was significantly depressed. This study suggests that MPA also exerts glucocorticoid-like effects on the intestinal tissue.
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PMID:Effect of medroxyprogesterone acetate on the digestive and absorptive functions of rat intestine. 623 Dec 5

The effect of a single oral dose of pp'DDT (100 mg/kg body wt.) has been studied on the intestinal uptake of certain nutrients and on brush border enzymes in rats. Intestinal uptake of leucine, and phenylalanine was considerably increased but there was no change in the absorption of glucose and alanine in DDT fed rats, compared to controls. The activities of brush border sucrase, alkaline phosphatase and Na+, K+-ATPase were significantly depressed in pesticide treated animals, but leucine aminopeptidase levels remained unaffected under these conditions. Analysis of the chemical composition of the microvillus membranes revealed a considerable enhancement in total lipids, phospholipids and triglyceride contents of the membranes in DDT exposed rats, but membrane protein, sialic acid and cholesterol fractions did not record any change. 1-14C-acetate incorporation into various lipid classes was studied to explain the observed increase in membrane lipids in DDT exposed animals.
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PMID:Effect of a single oral dose of pp'DDT on the absorption of nutrients in vitro and on brush border enzymes in rat intestine. 627 79


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