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)

Experimental diabetes alters intestinal mucosal function in a variety of ways including the enhancement of both active transport processes and the activity of brush-border hydrolases. These effects could result from changes in either intraluminal factors (food, bile, pancreatic enzymes) or extraluminal factors (blood flow, hormones, nervous impulses). To determine the role of intraluminal factors we studied the effect of diabetes on segments of jejunum completely excluded from luminal continuity, but with intact blood and nerve supply. Three weeks after construction of Thiry-Vella fistulas in rats, diabetes was induced with streptozotocin. Five days later sucrase activity was measured in both the excluded segment and in the proximal jejunum. Exclusion alone resulted in a 77 per cent decrease in mucosal protein content with no change in sucrase specific activity suggesting simply a diminished number of mucosal cells. Diabetes increased the specific activity of sucrase from 0.0643 mumoles per minute per milligram of protein plus or minus 0.0077 (SEM) to 0.1074 plus or minus 0.0182 (P smaller than 0.05) in the proximal jejunum and from 0.0467 plus or minus 0.0047 to 0.1040 plus or minus 0.0191 (P smaller than 0.02) in the excluded segment. These results provide conclusive evidence that the diabetic enhancement of sucrase activity is independent of intraluminal factors and must be the consequence of extraluminal changes.
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PMID:Enhancement of intestinal sucrase activity in experimental diabetes: the role of intraluminal factors. 12 49

Specific and total activities of lactase, sucrase and maltase were determined in the mucosa scraped from the proximal, mid and distal intestinal segments of nonpregnant and pregnant normal control and diabetic rats. In control rats, pregnancy was accompanied by a significant rise in total lactase activity of the entire intestinal mucosa. This was due to increased specific activity of the enzyme in the mid segment of the pregnant rats. In both nonpregnant and pregnant rats, diabetes was associated with marked enhancement of intestinal growth and with elevated specific and total activities of the three mucosal disaccharidases. In the pregnant diabetic rats, specific and total activities of the disaccharidases were about 30% lower than corresponding values in the nonpregnant diabetic rats.
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PMID:Intestinal disaccharidases in the rat: effects of pregnancy and diabetes. 13 Apr 71

Diabetes stimulates the functional activity of the intestinal brush border membrane with enhancement of both hydrolytic enzyme activity and membrane transport systems. To determine the mechanism of this effect, we studied the effects of streptozotocin diabetes on the metabolism of one membrane protein, sucrase-isomaltase, which increases its activity in diabetes. The protein was purified and an antiserum prepared. Sucrase-isomaltase from control and diabetic rats was immunologically identical as shown by Ouchterlony double-diffusion analysis of papain-solubilized mucosal proteins. The increase in sucrase enzyme activity in diabetic animals (31.0+/-1.4 U SEM 5 days after streptozotocin vs. 13.1+/-1.0 in controls) was the consequence of increased enzyme protein and not an alteration in catalytic efficiency as demonstrated by quantitative immunoprecipitin reactions. To account for increased sucrase-isomaltase protein in diabetes we studied papain-solubilized mucosal proteins labeled by injection of [(14)C]carbonate and [(14)C]leucine and analyzed incorporation into sucrase-isomaltase protein (anti-serum precipitable) and total protein (trichloroacetic acid precipitable). We found that diabetes did not affect the decay of labeled total protein, but prolonged the decay of labeled sucrase-isomaltase. t((1/2)) of sucrase-isomaltase was 4.4 h in control animals after [(14)C]carbonate injection and 8.8 and 10.2 h, respectively, 2 and 5 days after induction of streptozotocin diabetes. We obtained similar results in experiments with [(14)C]leucine with diabetes increasing t((1/2)) from 6 to 13.6 h. Diabetes did not appear to increase the rate of addition of sucrase-isomaltase to the brush border membrane, since it did not affect the 10- and 60-min incorporations of isotope into sucrase-isomaltase protein relative to incorporation into total protein and did not alter rate constants for synthesis calculated from the t((1/2)) and the change in enzyme mass over time.Thus, enhanced sucrase activity in the diabetic animal is the consequence of an increase in sucrase-isomaltase protein which develops because of a decrease in its rate of degradation.
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PMID:The intestinal brush border membrane in diabetes. Studies of sucrase-isomaltase metabolism in rats with streptozotocin diabetes. 14 62

Brush border sucrase and lactase activities are significantly elevated in alloxan-induced chronic diabetes and are restored to control levels after insulin treatment. Alkaline phosphatase and Mg-ATPase levels remain unchanged in diabetes, compared to a control group. Insulin treatment alone to control animals also led to enhanced activities of these enzymes.
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PMID:Effect of chronic alloxan diabetes and insulin administration on intestinal brush border enzymes. 14 19

In order to elucidate a possible relationship between (Na+ + K+)-activated ATPase and intestinal absorption of actively transported monosaccharides enzyme activity was measured in mucosal cells from alloxan diabetic rats. The general effect of increasing capacity of active, Na+-dependent transport processes in diabetes mellitus is associated with a significantly enhanced (Na+ +K+)-activated ATPase activity in mucosal homogenate from diabetic animals. To study the localization of these effects within the cell we isolated purified brush borders and their substructures. To enable a comparison to be made between preparation procedures of diabetic and control animals the fractions were controlled by electronmicroscopy and by measuring the sucrase activity. In the purified brush border fraction of alloxan treated rats there was no significant increase in (Na+ + K+)-activated ATPase activity. Based on these results we conclude that the (Na+ + K+)-activated ATPase in the basolateral membranes was increased in alloxan diabetes, and it seems very likely that this enzyme is involved in the regulation of Na+-dependent transport processes.
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PMID:[Effect of alloxan diabetes on (Na+ + K+)-activated ATPase in brush border membrane of the mucosal cell of rat small intestine]. 21 7

The effect of a new complex oligosaccharide (Bay g 5421) of microbial origin on human intestinal alpha-glucosidehydrolase activity was tested in mucosal homogenate from human small bowel biopsy specimens. The alpha-glucosidehydrolase inhibitor (alpha-GHI) exerted a potent inhibitory effect on glucoamylase, sucrase, and maltase, was minimally effective on isomaltase, and did not affect trehalase and lactase activity. Kinetic analysis revealed a fully competitive type of inhibition with a Ki of 1.3 x 10(-6) M; thus the inhibitor had a 15,000-fold higher affinity to the enzyme sucrase than its natural substrate sucrose. The new compound may prove to be useful in the study of carbohydrate maldigestion and malabsorption and may possibly be of therapeutic benefit in diabetes and obesity.
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PMID:Inhibition of human intestinal alpha-glucosidehydrolases by a new complex oligosaccharide. 44 22

Experiments on male rats showed that following subcutaneous injection of alloxan in a dose of 15 mg per 100 g of body weight amylolytic, invertase, glycyl-l-tyrosine dipeptidehydrolase activity of the mucosa of the small intestine altered differently. As a result, there occurred a deviation of the enzymatic spectrum from the normal characterized by a sharp increase (with the development of diabetes) of the activity of the carbohydrate hydrolysing enzymes (amylase and invertase) with a simultaneous reduction of the activity of the enzymes participating in protein (dipeptidase) and fat (monglyceridlipase) hydrolysis.
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PMID:[Effect of alloxan diabetes on the enzyme activity of the mucous membrane of the small intestine]. 72 80

It was taken 32 male Wistar rats, weighting between 130 g and 150 g, free feeding, to study the total and specific activities of lactase, invertase and maltase of small intestine of rats. The animals were divided by chance in 3 experimental and 1 control group. 1. group--Aloxanic diabetes rats: treated with 1 unit of NPH insulin every day: after the 4th day of aloxane administration, all rats were killed. 2. group--Aloxanic diabetes rats--treated for 5 days with 1 unit of NPH insulin every day; after the 5th day until the 7th they were treated with 4 units of NPH insulin and were also killed. 3. group--Hyperinsulinism rats--Normal rats were treated for 4 days with 4 units of NPH insulin every day. After the 5th day they were killed. 4. group--Control group--Normal rats, free feeding. They were observed during 4 days and were also killed. The results showed that none difference was observed in the 4 groups of rats about the total and specific activities of lactase, invertase and maltase of the small intestine. In this study, all the animals with aloxanic diabetes were treated with insulin. Then, it is possible that the insulin inhibited the stimulator effect of the diabetes upon the dissacaridases of the small intestine of the rats.
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PMID:[Insulin and disaccharidases levels of the small intestine of the rat (author's transl)]. 74 51

Chronic application (20 days) of glucagon in pharmacological doses induces mucosal transformation of the hyperregenerative type in the small intestine of the rat. This transformation is characterized by decreased villi, and increased crypt length. The morphological changes are accompanied by a reduction in glucose absorption in vivo as well as by decreased activities of lactase, sucrase and maltase. The findings demonstrate that hyperglucagonemia is not the cause for hyperplastic mucosal transformation, which is found in the experimental diabetes in the rat.
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PMID:[Functional and morphological studies on intestinal mucosa of the rat under chronic glucagon application (author's transl)]. 88 15

Endogeneous hyperglucagonemia is observed in experimental diabetes mellitus and semistarvation, conditions associated with an increased intestinal absorptive function. To examine whether glucagon might exert a similar adaptive response on intestinal digestive-absorptive function like experimental diabetes mellitus the effect of chronic glucagon administration on intestinal transport of 3-0-methyl-D-glucose, water, sodium, potassium, and D-glucose induced transmural potential difference (PD) was examined by an in vivo perfusion technique in rat small intestine. Chronic administration of glucagon (100 mug twice daily) for 5 days resulted in increased absorption of 3-0-methyl-D-glucose, water, sodium and potassium as well as in an increase of D-glucose induced PD. A similar, but more pronounced augmentation of D-glucose induced PD was observed in the jejunum of streptozotocin-diabetic rats. Disaccharidase (maltase, sucrase, trehalase, lactase) and alkaline phosphatase activities were not affected in intestinal mucosa of glucagon-treated rats compared to controls. It cannot be decided from these results whether hyperglucagonemia is responsible for the adaptive intestinal changes observed in experimental diabetes mellitus.
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PMID:Effect of chronic glucagon-administration on the digestive and absorptive function of rat small intestine in vivo. 98 1


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