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)

Inhibition of glucose-stimulated insulin release by exogenous insulin has been demonstrated in pancreatic islets to be associated with a decrease of the NADPH/NADP ratio and the pentose-phosphate cycle activity. Batches of five islets were incubated for 15 and 90 minutes in 1 ml. of KRB buffer with 2 per cent albumin containing 3 mg./ml. glucose and 0, 200, 400, or 800 microU./ml. of rat insulin, and the glucose-6-phosphate (G6P) and 6-phosphogluconate (6PG) contents were determined by enzymatic cycling. In response to a rise in the concentration of insulin, the 6PG/G6P ratio decreased. A close relationship was observed between this decrease of 6PG/G6P ratio and the net insulin release, the absolute rate of glucose oxidation via the pentose phosphate cycle, and the NADPH/NADP ratios measured under similar conditions. The results suggest that exogenous insulin, directly or indirectly, regulates the pentose cycle activity in the pancreatic islets at the G6P dehydrogenase step.
Diabetes 1977 Sep
PMID:6-Phosphogluconate/glucose-6-phosphate ratio in rat pancreatic islets during inhibition of insulin release by exogenous insulin. 1 30

A histochemical evaluation of the activity of chosen oxido-reductive enzymes of the cardiac muscle connected with the citric acid cycle, glycolysis and pentose shunt in the early experimental alloxan diabetes period in white rats has been carried out. Dehydrogenases: succinate, isocitrate and glucose-6-phosphate indicated a decrease in the enzymatic activity while the lactate dehydrogenase activity did not undergo any change. An increase in the intensity of the histoenzymatic reaction only concerned glutamate dehydrogenase. The presented histoenzymatic evidence of changes in the enzymatic activities may speak for the possibility of an existence of a direct diabetes influence on the cardiac muscle metabolism.
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PMID:Some histochemical observations on the myocardial metabolism in experimental conditions. Part II. 9 52

The increased level of the glycosylated hemoglobin (hemoglobin A1c) in the diabetic patient has proved to be an interesting clue to understanding the biochemical basis of the sequelae of diabetes. This minor hemoglobin, which arises as nonenzymatic postsynthetic addition of glucose to hemoglobin A, acts as an indicator molecule for the glucose environment over a 3-5-wk period prior to measurement. Reasoning that a similar glycosylation reaction could be occurring with other body proteins, we have studied the ocular lens. The lens, like the erythrocyte, is not dependent on insulin for glucose concentration in the extracellular milieu that would be elevated in the diabetic state. These studies have revealed that a high glucose in vivo or an increased glucose or glucose-6-phosphate concentration in vitro leads to the glycosylation of epsilon-amino groups of lysine residues in bovine and rat lens crystallins. This glycosylation imparts an increased susceptibility of the crystallins to sulfhydryl oxidation. Disulfide crosslinks result in the formation of high molecular weight aggregates and an opalescence of the crystallin solutions.
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PMID:Role of nonenzymatic glycosylation in the development of the sequelae of diabetes mellitus. 12 96

The articular cartilage of normal rats, of rats made diabetic with streptozotocin, and of rats made diabetic with streptozotocin and subsequently transplanted with isologous pancreatic islets was examined for the activities of enzymes engaged in the synthesis and degradation of glycosaminoglycans (mucopolysaccharides). The activities assayed were those of the degrading enzymes B-glucuronidase, B-acetyglucosaminidase, B-acetylgalactosaminidase, B-galactosidase, and those active in synthesis: uridine diphosphate dehydrogenase, glucose-6-phosphate dehyrogenase, and phosphofructokinase. In the diabetic animals all enzyme activities were increased, thos of the degrading enzymes more than those of the others. Implantation of pancreatic islets reversed the changes produced by diabetes, enzyme activities returning to near-normal levels.
Diabetes 1977 Aug
PMID:Enzyme studies in the articular cartilage of diabetic rats and of rats bearing transplanted pancreatic islets. 14 34

Numerous general metabolic systems are disturbed in association with psoriasis: the frequency of diabetes mellitus and of hyperuricaemia, lipid disturbances and a decrease in folates as a result of their excessive consumption by the skin. Cutaneous metabolism is also altered. Numerous compounds are formed in excess from glucose: amino acids, fatty acids and sterols, lactic acid--the formation of which persists in the corneal layer, ribose and ribulose--synthesised as a result of glucose-6-phosphate-dehydrogenase hyperactivity (role of the increased catabolism of dehydro-epi-androsterone) and uronic acids. The accumulation of glycogen is probably due to excessive synthesis and impaired breakdown. These abnormalities may exist to a lesser extent in healthy skin. In the corneal layer there are lipid vacuoles visible under the electron microscope. Lipogenesis is increased. The same may apply to lipolysis (blood NEFA are increased). Esterification of cholesterol is decreased. The utilisation of ATP by cell membranes is probably diminished (low ATP ase activity). The absence of formation of keratohyaline is due to persistence of the repression which normally prevents it in the mucus body. Renewal of collagen appears increased. The synthesis of DNA is increased in the lesions and neighbouring areas. It is possible that these various abnormalities are dependent upon modifications in the regulator systems of cyclic AMP and GMP, variations in which are however discussed.
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PMID:[The biochemistry of psoriasis]. 18 76

Recent evidence has suggested a role for the polyol pathway in pathogenesis of cell damage in diabetes Glucose may be phosphorylated to glucose-6-phosphate via hexokinase and enter glycolysis or reduced to sorbitol via aldose reductase to enter the polyol pathway. The poorly diffusible sorbitol is converted via sorbitol dehydrogenase to fructose. Hexokinase, aldose reductase and sorbitol dehydrogenase activities were measured in glomeruli (G) and small arteries (SA) taken from normal and diabetic human kidneys, Hexokinase in diabetic G was 1688, which was significantly decreased from normal, 3147 mmoles/kg-1/h-1. Alodse reductase was significantly elevated in diabetic G,56-6, compared to normal G,10-8 mmoles/kg-1/h-1. In contrast, sorbitol dehydrogenase was significantly depressed in diabetic G, 3-7 VERSUs 10-9 mmoles/kg-1/h-1. The enzymatic changes observed in diabetic G would facilitate accumulation of sorbitol and therefore could contribute to the progression of glomerulosclerosis. The activity of hexokinase was also significantly reduced in SA, whereas aldose reductase and sorbitol dehydrogenase were unchanged.
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PMID:Quantitative histochemistry of the sorbitol pathway in glomeruli and small arteries of human diabetic kidney. 48 51

In the blood of patients (104) with diabetes mellitus of various severity some energy metabolic indices (lactate, pyruvate, nonesterified fatty acids, and in some patients also glycogen and glycogenolytic activity of the blood), tissue oxygen tension and immunoreactive insulin were studied simultaneously. The glycogen content, a and b phosphorylase activity were determined in the liver and the skeletal muscles, and lactate, glycogen, and pyruvate in the blood of animals with experimentally induced diabetes mellitus (alloxan and immune diabetes). Changes in the energy metabolism were revealed in all forms of diabetes mellitus: in hyperinsulinism accompanying early forms of diabetes mellitus there was activation of anaerobic processes and tissue hyperoxygenation, and at the late stages of the disease a tendency to tissue hypoxia. Experimental diabetes was accompanied by glycogen reduction in the skeletal muscles together with the growth of b phosphorylase activity. This could be due to the reduction of glucose-6-phosphate in the muscles and to a disturbed activity of the other systems regulating glycogen metabolism.
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PMID:[Various characteristics of energy metabolism in diabetes mellitus]. 52 35

The alpha and beta anomers of commercially available D-(5-3H) glucose were separated by miniaturized Hudson-Dale procedures based on precipitation with acetic acid. Reflectometric measurements of the reactivity with matrix-bound glucose oxidase showed that the preparations were about 90 per cent pure with respect to anomeric composition. Nonradioactive anomers separated by the same procedures were analyzed by optic polarimetry and gas chromatography. The preparations were about 90 per cent pure with respect to anomeric composition and produced no peaks but D-glucose on trimethylsilylation and chromatography. Microdissected pancreatic islets of noninbred ob/ob-mice exhibited a linear production of 3H2O for three to nine minutes when incubated with 6 mM alpha-D-(5-3H) glucose, beta-D-(5-3H) glucose, or D-(5-3H) glucose in anomeric equilibrium; the three glucose preparations did not differ in their rate of conversion to 3H2O. The rate of 3H2O production increased with glucose concentration (3-21 mM) during incubations for three minutes and, again, there was no evidence for the metabolic activity's being dependent on the anomeric composition of the labeled sugar. When microdissected islets were perifused without glucose and suddenly exposed to 5-6 mM alpha-D-glucose or beta-D-glucose, the concentration of glucose-6-phosphate rose within five minutes and did not differ significantly between experiments with alpha-D-glucose and beta-D-glucose. In the same perifusion experiments, only alpha-D-glucose caused a pronounced stimulation of insulin secretion, the difference from beta-D-glucose being significant. The results indicate that the recognition of glucose as an insulin secretagogue does not only involve metabolism by glucose-6-phosphate. The possible roles of the sorbitol pathway and of hypothetical regulatory sites for the glucose molecule ("receptors") are briefly discussed.
Diabetes 1976 May
PMID:Further studies on the metabolism of D-glucose anomers in pancreatic islets. 77 24

UDPG-glycogen transferase existed mainly as D-form, depending on glucose-6-phosphate, and in minority as E-form in leukocytes of exudate of rabbits with diabetes and of control animals. The total enzymatic activity as well as the activity of D-form were almost the same both in leukocytes under diabetes and in control. The E-form activity accounted for 18% of the total enzymatic activity in leukocytes of diabetic rabbits and for 14% in leukocytes of control animals. Preliminary incubation of leukocyte homogenates at 37 degrees for 30 min led to decrease in the relation between the enzyme forms both in control rabbits and in animals with diabetes.
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PMID:[2 forms of UDPG-glycogen transferase in leukocytes of rabbit exudate in diabetes]. 88 8

In human erythrocytes activities of glucose-6-phosphate and lactate dehydrogenases were decreased approximately 2-fold in moderately severe and critical forms of diabetes mellitus, as compared with normal state. The lactate dehydrogenase activity was more distinctly decreased than the glucose-6-phosphate dehydrogenase activity. General medical treatment increased the activity of the enzymes (which catalyzed the ATP formation in erythrocytes) and normalized their relation.
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PMID:[Lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity in the erythrocytes in diabetes mellitus]. 102 30


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