Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The enzyme gamma-glutamyl transpeptidase is widely distributed throughout the body, notably kidney, seminal vesicles, pancreas, liver, spleen and brain. Being one of the enzymes of the gamma-glutamyl cycle, it is involved in aminoacid transport, catalysing a transpeptidation reaction between gamma-glutamyl peptides and most common amino acids. Methods of assay of the enzyme are based on its ability also to act on synthetic amides of glutamic acid; kinetic methods monitoring the release of p-nitroaniline from the substrate L-gamma-glutamyl p-nitroanilide are the most satisfactory. In diseases of the liver, the highest levels occur in association with cirrhosis, alcoholism, hepatic secondaries and cholestasis. As the enzyme is present in the endoplasmic reticulum of the hepatocyte, its activity is increased in situations leading to microsomal enzyme induction. Raised levels can also occur in pancreatitis, diabetes, myocardial infarction, congestive cardiac failure, chronic renal failure, cerebrovascular accidents, cerebral tumours and chronic obstructive pulmonary disease. Although the lack of specificity must be recognised, the estimation can be useful in the elucidation of some clearly defined problems arising during investigation of patients with suspected hepatic disease, especially where performed as part of a biochemical profile.
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PMID:Role of gamma-glutamyl transpeptidase activity in the diagnosis of hepatobiliary disease. 24 76

Amniotic fluid glucose (AF glu) was studied in 92 pregnancies complicated by maternal diabetes. An inverse relation between AF glu and gestational age was found: [AF glu (mg. per diciliter) = 160.9 -- 3.51 (weeks gestation); r = -0.47]. A direct relation between AF glu and severity of maternal diabetes was observed: mean AF glu (mg. per deciliter) = 24.6 +/- S.D. 12.3 in Class A, 41.2 +/- 25.5 in Class AD and 57.5 +/- 36.5 in Classes B-D. A positive correlation of AF glu with osmolality was observed [AF Osm (mOsm. per kilogram) = 250.7 + 0.22 AF glu; r = +0.50], but this relation was remarkable inconsistent in individual patients. Neither individual nor serial AF glu levels were of any prognostic value in predicting fetal condition or perinatal outcome.
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PMID:Amniotic fluid glucose in pregnancies complicated by diabetes. 83 81

The levels of gamma aminobutyric acid decreased, while glutamic acid and aspartic acid levels increased in the forebrain, and decreased in the mid and hind brain regions of frog, Rana cyanophlictis during alloxan diabetes. Since glutamic acid and GABA are intimately involved in the central nervous system (CNS) functions, the alterations occurring in their levels during alloxan diabetes may be significant in bringing about a correlation between the diabetic state and the altered functional dynamics of the CNS.
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PMID:Neurochemical correlates of alloxan diabetes: gamma amino butyric acid of amphibian brain. 89 69

Studies have been carried out on activities of lysosomal beta-N-acetylhexosaminidase (hex), beta-galactosidase (beta-gal), alpha-glucosidase (alpha-glu), and acid phosphatase (AP) in serum and urine from patients with juvenile diabetes and matched controls. There is a large increase in blood and urinary hex activity (the former presenting three distinct patterns of abnormality), a moderate increase in urinary beta-gal, and a small increase in urinary alpha-glu activity, but no elevation of blood or urinary AP in the diabetics. Urinary alpha-glu activity in the diabetics shows striking inhibition by glucose, and this may reflect a similar phenomenon in vivo. Although glycohydrolase activities are elevated in patients with no detectable microangiopathy, more striking changes may be observed in patients with severe small-vessel disease. These alterations may be associated with increased glycoprotein catabolism in the diabetic, an area in need of further studies in the human and experimental diabetic animal.
Diabetes 1976 May
PMID:Altered lysosomal glycohydrolase activities in juvenile diabetes mellitus. 126 40

High ascorbic acid (AA) levels in the aqueous humor and intraocular tissues, including the lens, are thought to protect against the harmful effects of photochemical and ambient oxidation reactions involving oxygen and its radicals. In addition, AA may have various metabolic functions, including structural collagen formation in intraocular tissues. Recent work showed that, in the guinea pig, reduced AA was concentrated in the aqueous and lens epithelium. These in vivo studies were extended to streptozotocin-induced diabetic rats and guinea pigs to explore the state of AA transport and passive L-glucose movement in the diabetic lens. A bolus dose of radiolabeled test molecules, including 14C-AA, 3H-L-glucose (L-glu), and 14C-3-O-methyl-D-glucose, was injected into the blood at time zero, and the time-dependent concentrations of these labeled molecules were determined as they move into the aqueous humor, lens epithelium and capsule, and interior compartments. These kinetic studies provided a unique measurement of the functioning state of passive and carrier transport mechanisms in situ in normal and diabetic animals. Diabetic animals (blood glucose, greater than 300 mg/dl) were categorized in terms of the length of time of uniform monitored drug-induced diabetes as short term (10-20 days); midterm (40-60 days), and long term (100+ days). In the rat lens epithelium, significant decrease occurred in the active movement of AA (control KEi, 0.693 +/- 0.062 [n = 12]; midterm drug-induced diabetes Ki, 0.192 +/- 0.054 [n = 10]; t-test P less than 0.001). The passive L-glu entry rate increased (control KEi, 0.0268 +/- 0.0053 [n = 12]; midterm drug-induced diabetes KEi, 0.0421 +/- 0.075 [n = 10]; t-test P less than 0.005). Thus, it was suggested that the drug-induced diabetic rat lens epithelium had lost some of its ability to concentrate AA to high levels and achieved epithelial levels only one- to twofold those of aqueous; control animals concentrated AA to levels of five- to eightfold those of aqueous within 20 min. By contrast, the rate of movement of L-glu from epithelium to stroma increased minimally (control KSi, 0.0116 +/- 0.021 [n = 12]; midterm drug-induced diabetes KSi, 0.0136 +/- 0.034 [n = 10]; t-test P less than 0.05). In addition, AA entry rate into lens cortex increased fourfold (control KSi, = 0.0018 +/- 0.0003 [n = 12]; midterm drug-induced diabetes KSi, 0.0081 +/- 0.024 [n = 10]; t-test P less than 0.001).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Alterations in ascorbic acid transport into the lens of streptozotocin-induced diabetic rats and guinea pigs. 138 45

High L-ascorbic acid (AA) levels in aqueous humor and intraocular tissues including lens and cornea are thought to protect against the harmful effects of the photochemical and ambient oxidation reactions involving oxygen and its radicals. Our pulse-chase studies follow a bolus of radiolabeled test molecules including [14C]L-ascorbic acid and [3H]L-glucose (L-glu) introduced into the blood at time t = 0, and determine the time-dependent concentrations of these labeled molecules as they move into aqueous humor, corneal endothelium and stroma tissues. Calculated entry and exit rate constants provide a representative measure of the functional state of passive and carrier mediated transport mechanisms in situ in normal and diabetic animals. Diabetic rats were categorized in terms of length of time exposed to a uniform, monitored streptozotocin (stz) diabetes as: short term (10-20 days); mid-term (40-60 days); and long term (100+ days). In the rat, we observed little change in entry rate of L-glu (a passive marker) into aqueous humor [control Ki = 0.0216 +/- 0.0021 (n = 14)/mid-term stz-diabetes Ki = 0.0202 +/- 0.0027 (n = 10)] and a modest decrease in the entry rate of AA into aqueous humor [control KAi = 0.0231 +/- 0.0022 (n = 14)/mid-term stz-diabetes KAi = 0.0201 +/- 0.0034 (n = 10)]. At corneal endothelium, we noted a significant decrease in the active movement of AA [control KE = 0.614 +/- 0.053 (n = 14)/mid-term stz-diabetes KE = 0.220 +/- 0.026 (n = 9)] while the passive L-glu entry rate remained essentially unchanged.+
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PMID:Decreased ascorbic acid entry into cornea of streptozotocin-diabetic rats and guinea-pigs. 142 66

We measured net uptake and release of amino acids in the brain of 7 nondiabetic and six diabetic subjects. Duration of insulin-dependent diabetes (IDDM) was 19.4 +/- 2.1 years. Arteriojugular vein measurements were performed before and after 120 minutes of insulin infusion and ensuing Biostator-regulated normoglycemia. Cerebral blood flow was measured during normoglycemia by 11-CH3-F and positron emission tomography. During hyperglycemia in the IDDM subjects, arterial concentrations of valine and leucine were higher, and those of glutamic acid and arginine lower, than in nondiabetic subjects. Insulin infusion lowered levels of most amino acids in both groups. Insulin treatment did not significantly affect the uptake or release of amino acids. Significant net uptake of branched-chain amino acids was noted in both groups, as well as uptake of lysine and phenylalanine in the IDDM subjects. The sum of measured differences was not different from zero in either group. Nitrogen balance depended on impressive release of glutamine from the brain (-963 +/- 147 and -960 +/- 303 nmol/100 g/min), which amounted to 73% and 69% of net release in nondiabetic and IDDM subjects, respectively. We conclude that balance between uptake and release of amino acids is similar in nondiabetic and in long-term IDDM subjects.
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PMID:Brain uptake and release of amino acids in nondiabetic and insulin-dependent diabetic subjects: important role of glutamine release for nitrogen balance. 153 41

Insulin receptor tyrosine kinase activity solubilized from hind limb muscle of control and streptozocin-induced diabetic (STZ-D) rats (2-3 wk) was studied with the substrates histone H2B and poly glutamic acid-tyrosine (glu-tyr) (4:1). Basal and insulin-stimulated kinase activities were inhibited when high concentrations of either substrate were added before initiation of phosphorylation with ATP. Under these conditions, insulin-stimulated activities of diabetic- and control-derived receptor kinase toward H2B were similar at 0.008 mg/ml H2B. However, higher concentrations of H2B (0.04-1 mg/ml) progressively reduced the ratios of diabetic-derived to control-derived receptor kinase activities to approximately 0.5. When inhibition of receptor kinase activities was prevented by allowing maximal autophosphorylation of insulin receptors before addition of H2B, kinase activity of diabetic- and control-derived receptors was similar at all H2B concentrations. Diabetic-derived insulin-receptor tyrosine kinase activity toward poly glu-tyr (4:1) was not significantly different from that of control rats. Under conditions of substrate inhibition (0.4 mg/ml H2B), insulin receptor H2B kinase activity from muscles of rats with severe diabetes (85 mg/kg STZ, 7 days) was significantly decreased, whereas the same activity from rats with moderate diabetes (50 mg/kg STZ, 7 days) was not significantly different from control rats. Insulin receptor alpha,beta dimers were not detectable in muscle preparations from control or diabetic rats. The data suggest that the impairment of muscle-derived insulin-receptor tyrosine kinase activity associated with insulinopenic diabetes reflects, in part, enhanced inhibition by some substrates. If solubilized insulin receptors and the exogenous substrates studied model in vivo events, impaired signaling of the muscle insulin receptor in insulinopenic diabetes may depend on the type and concentration of intracellular tyrosine kinase substrates and the severity of the metabolic derangements.
Diabetes 1991 Dec
PMID:Skeletal muscle insulin-receptor kinase. Effects of substrate inhibition and diabetes. 166 94

Plasma and urinary concentrations of different amino acids were investigated during diabetic ketoacidosis (DKA) and 12, 24, 72 hours after initiation of therapy. In DKA, plasma concentration of glutamic acid, aspartic acid, valine, leucine and isoleucine significantly increased while that of asparagine and glutamine decreased compared to levels in well-controlled diabetic patients. The urinary excretion of branched-chain amino acids, histidine, serine and threonine was elevated while those of glutamic acid, glutamine, glycine and taurine were reduced. Among the different amino acids, histidine excretion had the highest variability. A strong correlation was found between the urinary excretion of several amino acids and that of the beta-2-microglobulin characterizing tubular dysfunction. Changes in the excretion of different amino acids reflect the altered metabolic state and renal function due to DKA.
Diabetes Res Clin Pract 1991 May
PMID:Changes in plasma and urinary amino acid levels during diabetic ketoacidosis in children. 190 67

Glutamic acid decarboxylase (GAD; glutamate decarboxylase, L-glutamate 1-carboxy-lyase, EC 4.1.1.15), which catalyzes formation of gamma-aminobutyric acid from L-glutamic acid, is detectable in different isoforms with distinct electrophoretic and kinetic characteristics. GAD has also been implicated as an autoantigen in the vastly differing autoimmune disease stiff-man syndrome and insulin-dependent diabetes mellitus. Despite the differing GAD isoforms, only one type of GAD cDNA (GAD-1), localized to a syntenic region of chromosome 2, has been isolated from rat, mouse, and cat. Using sequence information from GAD-1 to screen a human pancreatic islet cDNA library, we describe the isolation of an additional GAD cDNA (GAD-2), which was mapped to the short arm of human chromosome 10. Genomic Southern blotting with GAD-2 demonstrated a hybridization pattern different from that detected by GAD-1. GAD-2 recognizes a 5.6-kilobase transcript in both islets and brain, in contrast to GAD-1, which detects a 3.7-kilobase transcript in brain only. The deduced 585-amino acid sequence coded for by GAD-2 shows less than 65% identity to previously published, highly conserved GAD-1 brain sequences, which show greater than 96% deduced amino acid sequence homology among the three species. The function of this additional islet GAD isoform and its importance as an autoantigen in insulin-dependent diabetes remain to be determined.
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PMID:Cloning and primary structure of a human islet isoform of glutamic acid decarboxylase from chromosome 10. 192 93


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