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

A technique for pancreatectomy was described for the American eel. In this fish, the operation was not followed by the typical signs of diabetes mellitus. Histodensitometric determination of liver glycogen showed no major differences between operated controls and pancreatectomized eels. The absence of a specific hyperglycemia, previously reported with the hexokinase method, was confirmed with the glucose oxidase technique; however, the more specific hexokinase method gave consistently lower values. Breakdown of adipose tissue and hyperlipemia were absent.
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PMID:Pancreatectomy in a teleost fish, Anguilla rostrata (American eel). 85 Mar 78

Decrease in the activity of hexokinase was found in soluble fraction of stomach smooth muscles of rabbits with alloxane diabetes. Administration of insulin into intact rabbits led to distinct decrease in the activity of lactate and malate dehydrogenases in cells of the stomach fundal part. In smooth muscles of rabbits with alloxane diabetes pyruvate was formed from lactate at a higher rate (increase in content of LDH1 and LDH2) and after administration of insulin into the animals--lactate was formed from pyruvate at an increased rate.
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PMID:[Effect of insulin and insulin deficiency on the activity of hexokinase, malate dehydrogenase, lactate dehydrogenase and its isoenzyme composition in the smooth muscle of the rabbit stomach]. 91 76

Studies of adipocyte metabolism were performed in twelve male subjects with normal plasma lipids and eleven male patients with Type IV or Type V hyperlipoproteinemia. Patients with obesity or diabetes mellitus were excluded from the study. Although all patients had normal glucose tolerance tests, the blood glucose levels during these tests were higher in the hyperlipoproteinemic patients than in the normal control subjects and the plasma insulin responses were even more strikingly elevated in the hyperlipemic group. Adipocytes isolated from hypertriglyceridemic subjects were larger than those obtained from normal individuals and exhibited increased activities of both Type I and Type II hexokinase and increased rates of glucose oxidation and lipogenesis from glucose. Cell size, hexokinase isoenzyme activities and rates of lipogenesis from glucose were all strongly correlated with each other, but none of these measurements were correlated with glucose oxidation. It is not known how the adipocyte abnormalities are related to the lipid transport disorder.
Diabetes 1975 Feb
PMID:Hyperinsulinemia and enlarged adipocytes in patients with endogenous hyperlipoproteinemia without obesity or diabetes mellitus. 112 8

Sodium fluoride was inadvertently added as a preservative to the urine of an eight-year-old boy with diabetes mellitus before urinary glucose was measured. On preliminary screening of the urine, the test by glucose oxidase paper reagent strip gave a negative reading for glucose, whereas quantitative urinary glucose assay by the coupled enzyme reaction (hexokinase-glucose 6-phosphate dehydrogenase) gave a glucose concentration of 81.5 g/liter. Inadvertent use of sodium fluoride as a urine preservative may cause a falsely negative result with the glucose tests involving oxidase.
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PMID:Inhibitory effect of fluoride on glucose tests with glucose oxidase strips. 113 42

Enzyme activities operative in glucose degradation and citrate cleavage pathway were studied in the adipose tissue of twenty-four patients with adult-onset diabetes and normal body weight, aged 59+/-9 years, and twenty-four matched controls. In normal tissue, type II (heat-inactivated) hexokinase moderately predominated over type I (heat-resistant). 6-Phosphofructokinase had an extremely low activity, which was by far the lowest among the ten glycolytic enzyme activities investigated, and which therefore might greatly limit the glycolytic rate. The level of glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase (decarboxylating) was elevated above that occurring in other tissues. This, especially if considered together with the low 6-phosphofructokinase activity, would suggest a major role of pentose cycle in glucose degradation. Of the citrate cleavage pathway enzymes, ATP citrate-lyase, although having a lower activity than malate dehydrogenase and malate dehydrogenase (decarboxylating) (NADP), was readily measurable, which contrasts with previous data by others. This finding is consistent with the occurrence of lipogenetic capacity in human adipose tissue. In diabetic tissue, there was a decreased activity, both on a protein and on a wet-weight basis, of enzymes concerned with the glucose entry into metabolic pathways, namely hexokinase (both type I and, especially, type II) and pentose cycle dehydrogenases, as well as of pyruvate kinase. This could be connected with the defective glucose utilization by adipose tissue in diabetes. Beside the above-mentioned dehydrogenases, malate dehydrogenase (decarboxylating) (NADP) was also diminished. The reduction of these NADPH-forming enzymes, which supply reducing equivalents for fatty acid synthesis, would suggest a depressed lipogenesis.
Diabetes 1975 Oct
PMID:Enzymes of glucose metabolism and of the citrate cleavage pathway in adipose tissue of normal and diabetic subjects. 118 27

Voluntary wheel running induces an increase in the concentration of the regulatable glucose transporter (GLUT4) in rat plantaris muscle but not in soleus muscle (K. J. Rodnick, J. O. Holloszy, C. E. Mondon, and D. E. James. Diabetes 39: 1425-1429, 1990). Wheel running also causes hypertrophy of the soleus in rats. This study was undertaken to ascertain whether endurance training that induces enzymatic adaptations but no hypertrophy results in an increase in the concentration of GLUT4 protein in rat soleus (slow-twitch red) muscle and, if it does, to determine whether there is a concomitant increase in maximal glucose transport activity. Female rats were trained by treadmill running at 25 m/min up a 15% grade, 90 min/day, 6 days/wk for 3 wk. This training program induced increases of 52% in citrate synthase activity, 66% in hexokinase activity, and 47% in immunoreactive GLUT4 protein concentration in soleus muscles without causing hypertrophy. Glucose transport activity stimulated maximally with insulin plus contractile activity was increased to roughly the same extent (44%) as GLUT4 protein content in soleus muscle by the treadmill exercise training. In a second set of experiments, we examined whether a swim-training program increases glucose transport activity in the soleus in the presence of a maximally effective concentration of insulin. The swimming program induced a 44% increase in immunoreactive GLUT4 protein concentration. Glucose transport activity maximally stimulated with insulin was 62% greater in soleus muscle of the swimmers than in untrained controls. Training did not alter the basal rate of 2-deoxyglucose uptake.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glucose transporters and maximal transport are increased in endurance-trained rat soleus. 139 70

Erythrocytes from young type I diabetic patients (n = 11), incubated in their plasma in anaerobic conditions, exhibited higher glucose consumption than cells from controls (n = 11). This increased metabolic activity is believed to reflect erythrocyte alterations dependent on the degree of metabolic control, as glucose consumption was significantly correlated to glycosylated haemoglobin (HbA1) and to glucose levels (P < 0.05 and P < 0.01 respectively). Red cell hexokinase (HK) and pyruvate kinase (PK) activities were similar in both groups whereas phosphofructokinase (PFK) activity was slightly higher in patients' cells (P < 0.05). No difference was found between patients and controls for red cell ATP and 2.3 diphosphoglycerate (2.3 DPG) levels. However, the concentrations of these glycolytic products seem also closely related to the glucose homeostasis in diabetes. Indeed, within the diabetic group, ATP levels showed a negative relationship with glucose level (P < 0.05) and 2.3 DPG a positive relationship with HbA1 (P < 0.05). In conclusion, higher glycolytic activity is present in young diabetic red cells. This activity as well as ATP and 2.3 DPG levels are related to the degree of short- or long-term diabetic control. These findings stress the importance of a careful metabolic control to avoid haematological disturbances.
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PMID:Erythrocyte metabolic alterations in type I diabetes: relationship to metabolic control. 144 91

It has been proposed that endogenous hexokinases of the pancreatic beta cell control the rate of glucose-stimulated insulin secretion and that genetic defects that reduce beta-cell hexokinase activity may lead to diabetes. To test these hypotheses, we have produced transgenic mice that have a 2-fold increase in hexokinase activity specific to the pancreatic beta cell. This increase was sufficient to significantly augment glucose-stimulated insulin secretion of isolated pancreatic islets, increase serum insulin levels in vivo, and lower the blood glucose levels of transgenic mice by 20-50% below control levels. Elevation of hexokinase activity also significantly reduced blood glucose levels of diabetic mice. These results confirm the role of beta-cell hexokinase activity in the regulation of insulin secretion and glucose homeostasis. They also provide strong support for the proposal that reductions in beta-cell hexokinase activity can produce diabetes.
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PMID:Expression of yeast hexokinase in pancreatic beta cells of transgenic mice reduces blood glucose, enhances insulin secretion, and decreases diabetes. 146 37

The present study examined the effect of vanadate on the activity of key enzymes of glycolysis and the level of fructose 2,6-bisphosphate (F-2, 6-P2) in the hearts of diabetic rats. A 20% decrease in the total hexokinase activity and 66% decrease in the type II isoenzyme was found in diabetic rat hearts. Vanadate treatment doubled the activity of type II hexokinase. Pyruvate kinase and phosphofructokinase 1 activity was reduced by 20% in diabetes, vanadate treatment restored the activity of the enzymes to normal. A 43% decrease in the cardiac F-2, 6-P2 level was found in diabetes of four weeks duration. A significant inverse correlation between blood glucose of experimental animals and the level of heart F-2, 6-P2 was observed. Vanadate treatment doubled the amount of F-2, 6-P2 in diabetic rat hearts.
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PMID:Vanadate treatment increases the activity of glycolytic enzymes and raises fructose 2,6-bisphosphate concentration in hearts from diabetic rats. 148 92

DNA polymorphisms in the glucokinase gene have recently been shown to be tightly linked to early-onset non-insulin-dependent diabetes mellitus in approximately 80% of French families with this form of diabetes. We previously identified a nonsense mutation in exon 7 in one of these families and showed that it was the likely cause of glucose intolerance in this dominantly inherited disorder. Here we report the isolation and partial sequence of the human glucokinase gene and the identification of two missense mutations in exon 7, Thr-228----Met and Gly-261----Arg, that cosegregate with early-onset non-insulin-dependent diabetes mellitus. To assess the molecular mechanism by which mutations at these two sites may affect glucokinase activity, the crystal structure of the related yeast hexokinase B was used as a simple model for human beta-cell glucokinase. Computer-assisted modeling suggests that mutation of Thr-228 affects affinity for ATP and mutation of Gly-261 may alter glucose binding. The identification of mutations in glucokinase, a protein that plays an important role in hepatic and beta-cell glucose metabolism, indicates that early-onset non-insulin-dependent diabetes mellitus may be primarily a disorder of carbohydrate metabolism.
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PMID:Human glucokinase gene: isolation, characterization, and identification of two missense mutations linked to early-onset non-insulin-dependent (type 2) diabetes mellitus. 150 86


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