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

Glucosylated albumin of human serum isolated by dye-ligand chromatography on blue Sepharose, was not found to be completely reducible by sodium borohydride. The percentage reducible hexose as judged by phenol-sulphuric acid reaction was in the range of 49.7 +/- 12.8 in control subjects (n = 24) and 53.8 +/- 14.2 in diabetics (n = 50). Increase in the level of total hexose bound to albumin and reducible hexose were equally significant in diabetes (P less than 0.001). Sodium chloride gradient elution during chromatography on blue Sepharose showed that glucosylated albumin had lesser affinity than the native protein to the matrix. It is proposed that an addition product between hexose and albumin is formed during nonenzymatic reaction and this adduct is fairly stable and is not reducible by sodium borohydride.
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PMID:Studies on sodium-borohydride-reducible hexose in glucosyl-albumin. 662 88

The binding of the lectins concanavalin A (Con A) and wheat germ agglutinin (WGA) to the luminal surface of lung alveolar epithelial cells was compared in normal rats and rats with streptozotocin-induced diabetes and their offspring. Lung tissue was lavaged, then fixed in situ with 3% glutaraldehyde. Buffer-rinsed slices of lung were incubated in Con A, WGA, or various control media. Lectin binding sites were visualized by the use of the peroxidase method. Normal neonates and those that were the results of diabetic pregnancies showed a hexose-specific Con A and WGA binding pattern qualitatively similar to that of normal and diabetic adults, respectively. In the normal animals, Con A binding sites were masked by sialic acid residues and were removable with alpha-mannosidase after neuraminidase treatment. In the diabetic adults and their offspring, one the other hand, Con A binding sites were readily accessible and were totally removed only by sequential treatment with alpha-mannosidase and alpha-glucosidase. WGA binding was essentially eliminated with neuraminidase in all animals except in the neonates from diabetic pregnancies, where N-acetyl-glucosaminidase was also required. The effects of maternal diabetes were reversible and occurred about Day 7 postpartum in the neonate. The effects were also reversible following insulin replacement in the diabetic adult.
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PMID:Diabetic pregnancy. Changes in lectin binding to the surface of rat lung alveolar epithelial cells. 668 9

We used the Oldendorf brain uptake index method to study the blood-brain barrier transport of several metabolic substrates in diabetes. Glucose transport into the brain was decreased by 1/3 in rats with moderate diabetes induced by prior injection of streptozotocin (65 mg/kg of body weight). The transports of mannose and the poorly metabolized hexoses 2-deoxyglucose and 3-O-methylglucose were similarly reduced. Likewise, brain glucose transport was decreased in rats with alloxan-induced diabetes. These alterations in brain hexose influx appeared to be related to chronic (1-2 days) hyperglycemia rather than to insulin-lack per se. Thus, starvation of the diabetic rats for 48 hr restored both the plasma glucose concentration and brain hexose transport to normal. Conversely, the substitution of 10% sucrose for their drinking water both increased plasma glucose and decreased hexose transport in insulin-treated diabetic rats. The 45% decrease in maximal glucose transport rate observed and the uniformity of diminished hexose transport probably imply a decrease in the number of available high-affinity transport carriers at the blood-brain barrier. This defect was specific for hexoses in that the transports of neutral and basic amino acids and of beta-hydroxybutyrate were not similarly affected. These results suggest that chronic hyperglycemia decreases the number of hexose carrier molecules available at the blood-brain barrier. Such an adaptation could operate to decrease the net flux of glucose into the brain during sustained hyperglycemia. It also may explain the abnormal sensitivity to abrupt blood glucose lowering in patients with diabetes mellitus.
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PMID:Metabolic fuel and amino acid transport into the brain in experimental diabetes mellitus. 675 47

To determine if inherent cellular differences in insulin sensitivity account for the insulin resistance of non-insulin-dependent diabetes, the effect of insulin on several aspects of cell glucose metabolism was compared in fibroblasts from diabetics and matched nondiabetic controls. The response of total cell glucose metabolism to insulin was assessed by measurement of 14C-glucose uptake. Insulin stimulated cell glucose incorporation in nondiabetic cells up to twofold with half-maximal stimulation at approximately 3 X 10(-9) M insulin. This was similar to that observed in diabetic cells. Insulin stimulation of I glycogen synthase activity was also compared in the cells from diabetics and nondiabetics. Both groups demonstrated a threefold increase in %I activity in the presence of insulin with half-maximal stimulation at approximately 2 X 10(-9) M. There were no differences between diabetics and nondiabetics in either magnitude of response or insulin concentration for half-maximal stimulation. Finally, insulin stimulation of hexose transport was compared in the two cell types using 2-deoxyglucose. In both groups hexose transport was elevated approximately 40% over baseline in the fibroblast in the presence of insulin, with half-maximal stimulation at approximately 2 X 10(-9) M insulin. No differences were found in insulin action on glucose metabolism in fibroblasts form diabetics and nondiabetics; these results may indicate that there are no inherent differences in cell sensitivity to insulin's glucoregulatory action in non-insulin-dependent diabetics.
Diabetes 1981 Jul
PMID:Type II diabetes and insulin resistance. Evidence of lack of inherent cellular defects in insulin sensitivity. 678 31

Glycosylated hemoglobins are minor components of human red cell hemoglobin, Structurally, they are closely related to adult hemoglobin and are formed nonenzymatically by condensation of glucose or other reducing sugars with hemoglobin A. Biosynthesis, structure and function of these modified hemoglobin molecules as well as their clinical implications have been the subject of extensive investigations recently. Glycosylated hemoglobins, which are increased two-to three fold in the red cells of diabetic patients, are becoming an accepted quantitative indicator for assessing the control of diabetes mellitus. Possible correlations of glycosylated hemoglobins with secondary complications and sequelae of the disease are also being investigated. Although the major site of the linkage of the hexose molecule to hemoglobin is at N-terminus of the beta-chains, it has recently been proposed that glycosylation of both alpha and beta-chains can take place at multiple sites including at the N-terminus of alpha chain can take place at multiple sites including at the N-terminus of a alpha chain and epsilon-amino group of several lysine residues on both alpha and beta chains. Glycosylation of hemoglobin is a nonspecific, nonenzymatic, posttranslational protein modification and has been used as a model for similar modifications in other macromolecules such as plasma and lens crystalline proteins, and even insulin. This review considers current investigations on the biochemistry, biosynthesis and clinical implications of glycosylated hemoglobins and other proteins.
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PMID:Glycosylated hemoglobins. 679 3

Methodologies for T and B lymphocyte quantitation, lymphocyte blast transformation (LBT) and carbohydrate (CHO) metabolism are important for assessing host lymphocyte response in the clinical laboratory. Modifications of methods for each of these techniques are presented. Results from studies of normal ambulatory adults, patients with diabetes mellitus, sickle cell disease and hyperlipidemia are reported. LBT of normal lymphocytes before and after ethanol exposure are examined. LBT during pregnancy is evaluated. T cell populations are abnormally high in black diabetics and decreased in patients with sickle cell anemia. B cell subpopulations are increased in patients with sickle cell anemia. LBT responses are decreased in maturity onset diabetes, during pregnancy and in patients with sickle cell disease. Ethanol in amounts attainable during human consumption results in significantly decreased LBT response. CHO metabolism (especially hexose monophosphate shunt [HMPS] and HMPS by pentose sugar recycling) is abnormal in diabetic lymphocytes. The low HMPS activity is partially reversible by treatment with prostaglandin synthetase inhibitors. Information related to lymphocytes in normal states remains to be collected by further clinical application of these techniques of quantitation and in vitro function.
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PMID:B and T lymphocytes: quantitation, function, and clinical applicability. 696 70

The influence of insulin on the intracellular free sodium and potassium ion concentrations ([Na+]i, [K+]i) and resting membrane potential of rat epididymal adipocytes was examined to determine its potential for mediating insulin's action on other cellular processes. Direct intracellular measurements of [Na+]i, [K+]i, and the resting membrane potential were made using ion-selective and conventional microelectrodes. The use of these microelectrodes enabled us to continuously monitor these parameters in the same cell before, during, and after periods of insulin stimulation of up to 20-min duration. The electrical potentials measured in these experiments remained unchanged when the cells were stimulated with insulin (0.01, 0.1, or 1.0 mU/ml). Varying the extracellular glucose concentration had no effect on these results. Our results provide the first direct measurement of [Na+]i and [K+]i in adipose tissue and clearly demonstrate that the response to insulin's association with its receptors on the cell surface and subsequent action on hexose transport and cellular metabolism does not involve a change in membrane potential or intracellular sodium and potassium ions.
Diabetes 1980 Dec
PMID:Insulin does not act by causing a change in membrane potential or intracellular free sodium and potassium concentration of adipocytes. 700 70

Glucogen synthesis in rat liver in vivo was measured by the incorporation of 3H from 3H2O into glycogen. In meal-fed rats incorporation and the incorporation of 3H into glycogen was linear up to 100 min. Before feeding glycogen concentration and the incorporation of 3H were both low; and both rose on feeding to give maximal values after 2-3h. The glycogen concentration was maintained for a further 5h but the incorporation of 3H rapidly declined to pre-feeding values. This shows that glycogen turnover was low in the post-prandial rat. Streptozotocin diabetes decreased the rise in glycogen concentration on feeding and had a similar effect on 3H2O incorporation. Both effects were reversed by insulin administration. The number of 3H atoms incorporated per glycogen glucose moiety formed in biosynthetic experiments (2.84 +/- 0.47) was relatively constant and allowed absolute biosynthetic rates to be calculated. Degradation of glucose from glycogen labelled by 3H2O showed that most of the 3H was located at C-2 and C-5. The incorporation would arise by rapid equilibration of hexose phosphates through phosphoglucose isomerase, transaldolase and triose phosphate isomerase.
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PMID:The use of tritiated water to measure absolute rates of hepatic glycogen synthesis. 730 13

Recently, a minor component of normal adult hemoglobin has been discovered. This hemoglobin is referred to as glycohemoglobin or Hgb AI, and it is made up of subgroups A-E (Hgb AIA-AIE). As the name implies, these hemoglobins are simply Hgb A with a hexose residue attached to each of the beta chains. The most important of the subgroups is Hgb AIC wich has a glucose molecule attached to the beta chains. The degree of glycosylation of Hgb A is directly dependent upon the concentration of blood glucose. Hgb AIC and total glycohemoglobin levels have been found to be two to three times greater in diabetics than in nondiabetics. It has also been determined that Hgb AIC and glycohemoglobin levels are reduced to near normal values when the blood glucose is well controlled. Since glycosylated hemoglobin levels represent a time-averaged blood glucose level, it is considered to be a better indicator of control than individual blood glucose levels. The glycohemoglobins are eluted quite easily before the major Hgb A component on ion exchange columns. Although Hgb AIC can be isolated by column exchange, most methods separate total glycohemoglobins, not just Hgb AIC. Thus, glycohemoblobin levels by ion exchange column separation may become the test of choice in monitoring treatment of diabetes mellitus.
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PMID:Glycosylated Hemoglobin: a literature review. 741 94

Insulin-like growth factor-I (IGF-I) has been inversely associated with low-density lipoprotein (LDL) cholesterol in normal women with slightly elevated cholesterol levels and hypothyroid women. More than 95% of IGF-I circulates bound to binding proteins (IGFBPs); of these IGFBP-1 is of particular interest as it is inversely regulated by insulin and is thought to inhibit the action of IGF-I and IGF-II. We examined the relationship between IGFBP-1 and LDL cholesterol in 41 healthy adult subjects. LDL cholesterol correlated with the body mass index (r = 0.40, P < 0.01), sex (r = 0.51, P < 0.001) and IGFBP-1 levels (r = 0.36, P < 0.02). LDL cholesterol did not correlate with age (r = 0.25, P = not significant) or IGF-I (r = 0.06, P = not significant). Upon multivariate regression analysis, sex, body mass index and IGFBP-1 were all independent predictors of LDL cholesterol (all P < 0.05). Elevated IGFBP-1 levels have been associated with an inhibition of serum IGF-I bioactivity in children with insulin-dependent diabetes. IGFBP-1 also appears to inhibit IGF-I hexose-stimulated uptake. IGFBP-1 may also be inhibiting the effect of IGFs on the cellular metabolism of LDL cholesterol.
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PMID:Insulin-like growth factor-binding protein-1 is correlated with low density lipoprotein cholesterol in normal subjects. 751 6


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