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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The specific activities of membrane-bound maltase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) in isolated brush border membranes (BBMs) of alloxan-induced diabetic, glucose-infused and maltose-infused rabbits were 30%, 140% and 160%, respectively, of those of control rabbits. Differences in the relative activities of trehalase (EC 3.2.1.28), another disaccharidase, in these groups were similar but less marked. However, the activities of two other marker enzymes of the brush border, alkaline-phosphatase and gamma-glutamyl transpeptidase, were similar in the 4 groups of rabbits. The decreases in the activities of the two disaccharidases were due to changes in the Vmax values of the enzymes without change in their Km values for maltose and trehalose. The maltase activities in the 4 groups showed similar dependences on Tris-HCl, KCl and NaCl. The electrophoretic profiles of the BBMs of the 4 groups on SDS-polyacrylamide gel showed slight differences. From these results, we conclude that diabetes, glucose infusion and maltose infusion probably change the concentrations of active enzymes in the BBM of the kidney in rabbits.
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PMID:Comparisons of maltase activities in kidney brush border membranes from normal, diabetic, glucose-infused and maltose-infused rabbits. 266 45

Miglitol (BAYm 1099), an alpha-glucosidase inhibitor, reduces the postprandial increase of blood glucose and serum insulin levels in type II (non-insulin-dependent) diabetes mellitus, as shown in short-term studies. In this study, the effects of long-term miglitol treatment on metabolic control, C-peptide secretion, hepatic glucose output, and peripheral insulin sensitivity (euglycemic clamp) were tested in 15 type II diabetic patients (8 receiving insulin, 7 receiving oral hypoglycemic agents). For 8 wk they received either miglitol (300 mg/day) or placebo with a double-blind crossover design that had a 4-wk washout period between treatments. Miglitol therapy induced a reduction of postprandial blood glucose levels (miglitol compared with placebo; areas under the curve; P less than .002), whereas fasting blood glucose levels were not influenced. Miglitol caused a slight reduction of glycosylated hemoglobin levels (mean +/- SE miglitol and placebo 9.50 +/- 0.3 and 10.0 +/- 0.4%, respectively; P less than .05), which was more pronounced in insulin-treated patients. Miglitol caused a reduction of postprandial C-peptide increase (P less than .03). Hepatic glucose output (both in the basal state and during euglycemic clamp conditions) and peripheral insulin sensitivity were not influenced by miglitol therapy. Specific side effects were observed in 11 patients; in 6 patients only to a moderate degree. Long-term miglitol treatment induces a persistent reduction of postprandial blood glucose increase. This effect is more pronounced in type II diabetic patients on insulin therapy, which can cause a moderate improvement of overall metabolic control.
Diabetes Care 1989 Sep
PMID:Effects of 8-wk alpha-glucosidase inhibition on metabolic control, C-peptide secretion, hepatic glucose output, and peripheral insulin sensitivity in poorly controlled type II diabetic patients. 267 93

Acarbose, a potent alpha-glucosidase inhibitor, represents a new concept for the treatment of metabolic disorders, and particularly diabetes mellitus. It slows the absorption kinetics of dietary carbohydrates by reversible competitive inhibition of alpha-glucosidase activity, and so reduces the post-prandial blood glucose increment and insulin response. For these reasons, the drug has been successfully used not only in the treatment of type I or type II diabetes, but also in the management of reactive hypoglycemias and dumping syndrome. In addition, some data suggest a possible role in the treatment of type IV hyperlipidemia. Because of the delay in absorption of oligo- and disaccharides resulting from its administration, a colic bacterial fermentation occurs, accounting for the frequent abdominal discomfort mentioned by the patients. These side effects would be lessened with the second generation glucosidase inhibitors now in progress.
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PMID:[Alpha-glucosidase inhibitors: a new therapeutic approach in diabetes and functional hypoglycemia]. 267 46

BAY m1099 (a 1-deoxynojirimycin derivative) is a glucose analogue which is an alpha-glucosidase inhibitor. Its effects on post-prandial blood glucose and insulin levels was compared with a placebo in 12 healthy male volunteers (6 Blacks and 6 Whites). It produced a similar, significant depression of post-prandial blood glucose and insulin levels when the groups were assessed separately and when the data were pooled. Although blood insulin levels in Whites were higher than in Blacks, as previously reported, the difference was not statistically significant and did not appear to influence the response to the drug. BAY 1099 produced no objective or subjective untoward effects and appears to warrant further investigation as an adjuvant to dietary control of diabetes mellitus.
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PMID:The effect of a 1-deoxynojirimycin derivative on post-prandial blood glucose and insulin levels in healthy black and white volunteers. 293 61

In a placebo-controlled double-blind randomised group comparison, the tolerability and metabolic effect of emiglitate, a new second-generation alpha-glucosidase inhibitor, was evaluated in 10 Indians with non-insulin-dependent diabetes mellitus being treated with sulphonylureas. Patients on emiglitate showed a decrease in postprandial plasma glucose levels (means 10 +/- 0.94; 10.1 +/- 0.97 mmol/l) compared with the levels in the run-in period (mean 11.4 +/- 1 mmol/l) but the difference was not significant. However, the emiglitate group showed a significantly greater decrease while on the drug compared with the placebo group at the end of the 1st week (P less than 0.01). The Hb A1 levels in those on emiglitate decreased significantly a week after cessation of therapy (mean 7 +/- 0.81%) compared with the run-in levels (mean 9.4 +/- 1.79%; P less than 0.02). The drug was well tolerated and caused no haematological or biochemical abnormalities.
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PMID:The clinical efficacy of a second-generation alpha-glucosidase inhibitor in non-insulin-dependent diabetic patients. 295 75

Two studies of the new alpha-glucosidase inhibitor, miglitol, in patients with non-insulin-dependent diabetes mellitus (NIDDM) are reported. In the first, 13 patients, poorly controlled on sulphonylureas, received miglitol 50mg three times daily for 4 weeks. Post-prandial blood glucose was reduced after breakfast, lunch, and tea compared with placebo (p less than 0.05-0.01) but there was no improvement in fasting blood glucose, serum fructosamine or haemoglobin A1. In a dose-response study the effect of a single dose of miglitol (0,50,100,150 or 200mg) on post-prandial glycaemia after a test breakfast was assessed in 20 patients with mean +/- SEM fasting blood glucose 9.9 +/- 0.4 mmol/l. With 50mg miglitol, there was a significant reduction in blood glucose from 30 to 120 min post-prandially compared with placebo. Increasing doses of miglitol further depressed the post-prandial rise in blood glucose and with 200mg there was no significant change from fasting levels. Side-effects were limited to flatus and loose stools particularly with the higher doses but were not severe. Miglitol effectively reduces post-prandial blood glucose rise in NIDDM with as little as 50mg but there is considerable individual variation. Larger doses may be necessary in patients already poorly controlled on sulphonylureas.
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PMID:Alpha glucosidase inhibition in the treatment of non-insulin-dependent diabetes mellitus. 296 27

Postprandial hyperglycemia in diabetic patients can be modified by delaying the digestion and/or absorption of dietary carbohydrates. We have studied an orally active alpha-glucosidase inhibitor, Bay 1099, in normal volunteers to determine whether these inhibitors can decrease postprandial rises in serum glucose without causing gastrointestinal symptoms or significant fecal caloric wastage. Six subjects were given 25, 50, or 100 mg of Bay 1099 or placebo before meals for 1 week, each with a 1-week washout period. Fasting and postprandial concentrations of glucose, insulin, glucagon, enteroglucagon, and gastrointestinal inhibitory peptide (GIP) were measured after the first and last dose of Bay 1099, and the fecal excretions of protein, fat, fiber, and total calories were measured on the last three days of each diet. The passage of unabsorbed carbohydrate into the colon was determined by breath hydrogen analysis three times during each study week. Increasing doses of Bay 1099 were found to decrease the postprandial rise in serum glucose concentration, delay the time to peak insulin concentration, and decrease the output of GIP after the meal. No adaptation was apparent after 1 week of therapy. A dose of inhibitor (50 mg tid), which greatly improves postprandial glucose and hormone output in diabetes, was associated with minimal symptoms and no excess fecal caloric losses. Thus, glucosidase inhibitors such as Bay 1099 may be useful in the management of patients with carbohydrate intolerance.
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PMID:Intestinal and metabolic responses to an alpha-glucosidase inhibitor in normal volunteers. 305 29

To examine the function of islet lysosomal enzymes in islet hormone secretory mechanisms, we investigated the effects of the lysosomotropic drug chloroquine on islet lysosomal enzyme activities and basal as well as stimulated insulin and glucagon secretion. Chloroquine, added to islet homogenates, did not affect the activities of the lysosomal enzymes acid amyloglucosidase, acid alpha-glucosidase, or N-acetyl-beta-D-glucosaminidase. The activity of acid phosphatase, however, was inhibited at a high concentration of chloroquine (10(-3) M). When injected together with glucose, chloroquine (2 or 10 mumol/kg) inhibited the peak plasma insulin response. Similarly, at 24 hrs after chloroquine injection (100 mumol/kg), the plasma insulin response to glucose was reduced. In contrast, islets isolated from mice pretreated 24 hrs before with chloroquine, displayed glucose-stimulated insulin secretion in vitro that was not different from controls. Such islets showed, furthermore, enhanced activities of the enzymes acid phosphatase and neutral alpha-glucosidase but not of acid amyloglucosidase, acid alpha-glucosidase or N-acetyl-beta-D-glucosaminidase. Arginine-stimulated insulin response in vivo displayed a complex pattern; it was increased when arginine was injected together with chloroquine but decreased at 24 hrs after chloroquine administration. Arginine-stimulated glucagon secretion was not affected by chloroquine. We conclude that chloroquine pretreatment 24 hrs prior to glucose injection decreases glucose-stimulated insulin secretion in vivo by mechanisms that are not correlated to an inhibitory action on islet activities of glycogenolytic lysosomal enzymes.
Diabetes Res 1988 Nov
PMID:Islet hormone secretion and islet lysosomal enzyme activities in the mouse: effects of chloroquine. 307 44

The glucose-producing amylolytic activity in pancreatic islet tissue was characterized with regard to its properties with glycogen (amyloglucosidase) and maltose (maltase) as substrate, its optimum activity in islets from different strains of mice (NMRI, CBA and C-57BL) and after fasting, and its relation to the insulin secretory response after different secretagogues in vivo. Additionally the effects and fate of injected fungal acid amyloglucosidase were assessed. In the pancreatic islets of NMRI mice both the glycogen-splitting activity and the maltose-splitting activity displayed latency and an acid pH-optimum of about 5.0. After differential centrifugation a significant part of amyloglucosidase activity was found to be confined to the mitochondrial-lysosomal fraction. In crude islet homogenate the apparent Km for maltose at pH 5.0 was 2.1 mM. No Km for glycogen could be given because of complex kinetics in the presence of this substrate. The maltase activity was about 30% lower than the amyloglucosidase activity in islet tissue from NMRI mice. The reverse pattern was observed in the liver. Moreover, the liver amyloglucosidase activity was only one fourth of that of the islet tissue. The amyloglucosidase but not the maltase activity in islet tissue from CBA mice was lower than in islets from NMRI mice. Both activities were very low in islets from C-57 mice. A 24 hr fasting period reduced the amyloglucosidase but not the maltase activity in islets from NMRI mice. The insulin secretory response in vivo to an i.v. arginine load in the different strains and after fasting displayed the same pattern as the islet amyloglucosidase activity, whereas the insulin response following a glucagon injection was largest in the C-57 strain and unaffected by the fasting state. Pretreatment of mice with 0.05 mumol/kg of highly purified fungal amyloglucosidase, moderately (about 35%) enhanced the insulin secretory response to arginine, did not affect the response to glucagon, and greatly (about 100%) enhanced the response to glucose and tolbutamide. Moreover, treatment of mice with lysosomal stabilizers (glucocorticoids) reduced the insulin response to sulphonylureas and glucose, had no effect on the insulin response to beta-adrenergic and cholinergic stimulation, and increased ACTH-induced insulin release. A lysosomal labilizer (progesterone) enhanced the insulin response induced by glucose and tolbutamide.(ABSTRACT TRUNCATED AT 400 WORDS)
Diabetes Res 1986 Jan
PMID:Islet amyloglucosidase activity: some characteristics, and its relation to insulin secretion stimulated by various secretagogues. 308 68

The activities of intestinal disaccharidases are known to be responsive to changes in the dietary intake of carbohydrates in the adult rat. Little is known, however, regarding the activities of these enzymes in obese subjects and how they are affected by differing carbohydrate intakes. To evaluate the effect of carbohydrate intake on the activity of intestinal disaccharidases in obesity, we used the genetically obese mouse C57BL/6J obob as an experimental model. Representing an example of early-onset obesity and mature-onset diabetes, this animal is characteristically hyperinsulinemic and hyperglycemic. Groups of obese mice and lean littermates were fed for 7 weeks equal amounts of either high-dextrose or low-dextrose isoenergetic diets. Sucrase, maltase, and lactase activities were measured on intestinal homogenates from the proximal and middle portions of the jejunoileum (upper and lower jejunum). Results were expressed as activity per tissue protein as well as total activity. Obese mice were found to have consistently greater total activity of both sucrase and maltase than their lean littermates, mostly as a result of increased intestinal size. Total lactase activity, however, was similar in the upper jejunum in both obese and lean mice, largely related to a decreased specific activity in obese mice. All mice fed the high-dextrose diet had significantly increased total activity of all disaccharidases studied when compared to the low-dextrose-fed animals, except for the lactase activity in the lower jejunum, where no differences were found in either group. Increases in activity related to high carbohydrate intake were a result of increases in specific activity.
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PMID:Effect of a high-dextrose diet on sucrase and lactase activity in jejunum of obese mice (C57BL/6J obob). 309 6


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