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)

The activity of five glycohydrolases was measured in the plasma of Chinese hamsters from eight highly inbred lines in the Upjohn colony. The diabetic animals showed elevated activities of plasma beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase but similar activities of plasma alpha-D-glucosidase and alpha-D-galactosidase to the nondiabetic animals. Line-specific variation was observed in all five enzymes and anomalies were especially evident in N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase activity. In two diabetic lines, AC and Z, activities of these two enzymes were not elevated although significant correlation was found with blood sugar levels. The pronounced difference in the plasma activity of N-acetyl-beta-D-glucosaminidase in two diabetic lines, XA and AC, did not involve plasma inhibitors or activators, as evidenced by the coincidence in observed and calculated activities in mixed plasma samples, or specific isozymes, concluded from the similar elution profiles on ion-exchange column and thermostability curves. These data suggest that diabetes-related changes in plasma glycohydrolase activities are dictated by genetic factors and may be involved in the development of complications.
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PMID:Acid glycohydrolase in Chinese hamster with spontaneous diabetes. IV. Diabetes- and line-dependent variation in plasma enzyme activity. 21 99

1. Six weeks after the injection of streptozotocin at 125 mg/kg i.p. in the AV line nondiabetic Chinese hamsters, the animals showed hyperglycemia, increased kidney, pancreas and stomach weights and stomach glucagon contents and depletion of insulin and glucagon in the pancreas. 2. Plasma beta-D-galactosidase and N-acetyl-beta-D-glucosaminidase were elevated; whereas alpha-D-glucosidase was decreased and alpha-D-galactosidase remained unchanged in the plasma. 3. In the kidney, streptozotocin-diabetes led to depression of alpha-D-mannosidase, beta-D-fucosidase and N-acetyl-beta-D-glucosaminidase activities in both 12,000 g supernatant and precipitate fractions, decreases in alpha-D-glucosidase in the supernatant only and no change in alpha-L-fucosidase, alpha-D-galactosidase, beta-D-galactosidase and beta-D-glucuronidase. 4. In the liver, significant increases in N-acetyl-beta-D-glucosaminidase, alpha-D-galactosidase, beta-D-galactosidase, beta-D-fucosidase, beta-D-glucosidase and alpha-D-mannosidase were found in either the supernatant or the precipitate fraction of the diabetic animals. The data indicate diabetes-dependent tissue-specific changes in glycohydrolases in the Chinese hamster.
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PMID:Alterations in glycohydrolase activities in streptozotocin-diabetic Chinese hamsters (Cricetulus griseus). 31 16

The serum concentrations of FSH, LH, prolactin, testosterone, and estradiol and the enzymatic activities of hyaluronidase, glucosidases (alpha-glucosidase, beta-glucosidase, alpha-mannosidase, N-acetyl-beta-D-glucosaminidase, beta-glucuronidase, and beta-galactosidase), lactate dehydrogenase and its isoenzymes (LDH1, LDH2, LDH3, LDH-X, LDH4), and total proteins were measured in the semen of 69 subjects (8 normozoospermic controls, 7 secretory, and 54 excretory azoospermic subjects). FSH levels rose with the deterioration in spermatogenesis and served to differentiate the secretory from the excretory azoospermias. The only source of hyaluronidase and LDH-X in the ejaculate is the spermatozoa. alpha-Glucosidase activity essentially originates in the epididymis. The seminal determination of alpha-glucosidase and, to a lesser extent, alpha-mannosidase and N-acetyl-beta-D-glucosaminidase helps rapidly, sensitivity, reliably, and noninvasively to differentiate secretory azoospermias (with higher enzymatic activity) from the excretory type (less enzymatic activity) and may be of use in identifying with a certain degree of reliability the site of obstruction in the male genital tract.
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PMID:Enzyme and hormonal markers in the differential diagnosis of human azoospermia. 153 Mar 67

Using different conditions for incubation and fluorometry with 4-methylumbelliferylglycosides as substrates, we demonstrated the presence of acid alpha-glucosidase, "renal" alpha-glucosidase, N-acetyl-beta-D-glucosaminidase A, and N-acetyl-beta-D-glucosaminidase B in freshly drawn normal human serum. The acid alpha-glucosidase enzymatic activity was determined at pH 4.0 in 0.1 mol/L Tris reagent, whereas the renal isoenzyme activity was determined at pH 5.6 in presence of 0.05 mol/L turanose reagent. N-Acetyl-beta-D-glucosaminidases A and B were determined by their different behaviors on heating. The corresponding reference intervals for each enzyme were calculated from results for 40 controls: acid alpha-glucosidase (0.024 +/- 0.010 U/L), renal alpha-glucosidase (0.035 +/- 0.012 U/L), N-acetyl-beta-D-glucosaminidase A (10.2 +/- 2.9 U/L), and N-acetyl-beta-D-glucosaminidase B (4.4 +/- 2.1 U/L).
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PMID:alpha-Glucosidase and N-acetyl-beta-D-glucosaminidase isoenzymes in serum. 154 Oct 4

We have previously presented evidence for the involvement of islet acid amyloglucosidase, a lysosomal glycogen-hydrolyzing enzyme, in certain insulin secretory processes. In the present investigation, we studied whether differential changes in islet amyloglucosidase activity could be related to the insulin secretory response to glucose. It was observed that the dose-response curve for glucose-induced insulin response in vivo was shifted to the left by pretreatment of mice with purified fungal amyloglucosidase. In enzyme-pretreated mice, the ED50 was 2.1 mmol/kg glucose as compared with 5.7 mmol/kg in saline-pretreated controls (p less than 0.005). Also, the maximal insulin response to glucose was enhanced by amyloglucosidase pretreatment. Parenteral administration to mice (four injections during 2 days) of the pseudotetrasaccharide acarbose, a recognized inhibitor of intestinal alpha-glucosidases, surprisingly induced a marked increase in the activities of islet acid amyloglucosidase (+ 120%; p less than 0.001) and acid alpha-glucosidase (+ 45%; p less than 0.01) without affecting the activities of other lysosomal enzymes such as acid phosphatase and N-acetyl-beta-D-glucosaminidase. No effect on the microsomal neutral alpha-glucosidase was recorded. Moreover, in these mice, the insulin secretory response to glucose was enhanced both at a maximal dose of glucose 11.1 mmol/kg and at a dose in the ED25-ED50 range, 3.3 mmol/kg (p less than 0.005). Direct addition of acarbose to islet homogenates strongly suppressed acid amyloglucosidase activity, the EC50 being approximately 1 microM. Acid alpha-glucosidase activity was also strongly inhibited, whereas the activities of acid phosphatase and N-acetyl-beta-D-glucosaminidase were unaffected. Neutral alpha-glucosidase was slightly suppressed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The relationship of islet amyloglucosidase activity and glucose-induced insulin secretion. 159 57

The trypanocidal drug suramin is known to concentrate in lysosomes and to depress the activity of different lysosomal enzymes. We have previously shown that suramin can inhibit the activity of the islet lysosomal enzyme acid amyloglucosidase, a glycogenolytic glucose-producing hydrolase, which seems to be involved in certain insulin-secretory processes. In the present investigation we studied the pH dependency and dose-response effects of suramin on islet lysosomal enzyme activities as well as the effect of suramin treatment on the insulin-secretory response to various secretagogues in mice. It was found that two injections of suramin (0.18 mmol/kg) to normal NMRI mice at -24 and -2 h induced a moderate depression of the activities of islet acid amyloglucosidase (-22%) and acid phosphatase (-13%), whereas no effect was recorded for the activities of acid alpha-glucosidase, N-acetyl-beta-D-glucosaminidase and the non-lysosomal enzyme neutral alpha-glucosidase. Direct addition of different concentrations of suramin to islet homogenates showed that the drug was a potent inhibitor of acid amyloglucosidase and acid alpha-glucosidase at pH 4.0. At pH 5.0, suramin induced a large increase in acid alpha-glucosidase activity, whereas acid amyloglucosidase and acid phosphatase were inhibited. Suramin-injected mice showed a reduced insulin-secretory response to the sulphonylurea drug glibenclamide (-45%), whereas the insulin response to the cholinergic agonist carbachol or the phosphodiesterase inhibitor IBMX (1-isobutyl-3-methylxanthine) was unaffected. It is concluded that suramin inhibits islet acid amyloglucosidase activity in vivo and in vitro, whereas its effect on acid alpha-glucosidase is complex and pH dependent.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of the lysosomotropic drug suramin on islet lysosomal enzyme activities and the insulin-secretory response induced by various secretagogues. 172 7

The influences of glucose, the benzothiadiazide derivative diazoxide (an inhibitor of insulin release), and the potent non-glucose insulin secretagogue 3-isobutyl-1-methylxanthine (IBMX) on insulin secretion and the activities of 3 different lysosomal enzymes were studied in isolated mouse islets. We found that the increase in insulin secretion during a 4 hr incubation period in the presence of 16.7 mM glucose was accompanied by an increase in islet activities of the lysosomal enzymes acid amyloglucosidase and acid alpha-glucosidase. These alpha-1,4-glucoside splitting enzyme activities were increased by 45-55% (p less than 0.01). No influence by glucose was encountered for the activities of N-acetyl-beta-D-glucosaminidase or the non-lysosomal neutral alpha-glucosidase. Upon incubation with 0.2 mM diazoxide and glucose (16.7 mM) the glucose-induced insulin secretion was markedly suppressed and no significant increase in islet lysosomal enzyme activities was observed. On the other hand, insulin secretion induced by IBMX to the same magnitude as with 16.7 mM glucose, was accompanied by an increase in islet activity of N-acetyl-beta-D-glucosaminidase (p less than 0.05), whereas no apparent changes in acid amyloglucosidase and acid alpha-glucosidase activities could be detected. In conclusion, the determination of lysosomal enzyme activities in isolated mouse islets revealed that glucose was able to induce an increased activity of glucose producing glycogenolytic acid hydrolases under conditions when a concomitant insulin secretion occurred.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Insulin secretion and lysosomal enzyme activities in isolated mouse islets. Effects of glucose, diazoxide and isobutylmethylxanthine. 243 78

The activities of lysosomal maltase in the serum, urine and kidney were determined in rats with diabetes induced by streptozotocin (STZ, 75 mg/kg, i.p.) and compared with the changes in N-acetyl-beta-D-glucosaminidase (NAG) activity. Moreover, effects of insulin on maltase and NAG activities of the serum, urine and kidney in diabetic rats were studied. The following results were obtained: 1) The serum maltase activity within 24 hr after administration of STZ was influenced by insulin secretion. 2) Significant increases in blood urea nitrogen (BUN) levels were observed from the 3rd week after a single administration of STZ. The serum insulin level significantly decreased at 3 weeks after treatment of STZ. In this time, maltase activity in the serum rapidly increased, while the enzyme activity in the kidney decreased considerably. On the other hand, the changes in NAG activities in the serum, urine and kidney after administering STZ were almost similar to those in maltase activities. 3) There were positive relationships between maltase and NAG activities in the serum and urine in diabetic rats, respectively. 4) When lente insulin (2U) was subcutaneously injected once daily for 20 days from 24 hr after administration of STZ, NAG activities in the serum and kidney approached to the control levels. However, maltase activities in the group treated with insulin were significantly higher in the serum and kidney than those in the control group.
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PMID:[Effects of insulin on maltase and N-acetyl-beta-D-glucosaminidase (NAG) activities of serum and kidney in experimental diabetic rats]. 253 Jan 41

Urinary excretions of beta 2-microglobulin (beta 2M), N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase, beta-glucuronidase, acid and neutral alpha-glucosidase as indicators of proximal tubular dysfunction were measured in patients with acute upper and lower urinary tract infection (UTI) and fever of non-renal origin. The sensitivity of beta 2M was 67% and of NAG 49% as assessed in more than 100 episodes of acute pyelonephritis. Combined use of beta 2M and NAG increased the sensitivity to 75%. The degree of beta 2-microglobulinuria and enzymuria was comparable in patients with acute pyelonephritis and fever due to non-renal infections. The excretion of beta 2M and the various enzymes was too variable and unpredictable in individual cases to be useful as diagnostic indicator. In localizing an acute UTI, tests for proximal tubular dysfunction seem to be of no more clinical value than properly measured body temperature.
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PMID:Diagnostic potential of urinary enzymes and beta 2-microglobulin in acute urinary tract infection. 287 89

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.
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PMID:Islet hormone secretion and islet lysosomal enzyme activities in the mouse: effects of chloroquine. 307 44


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