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

Both adrenalectomy and chemically induced diabetes mellitus cause a marked decrease of pancreatic amylase activity in rats, but it is unknown whether these effects are the result of a direct or indirect mechanism. The synthesis of various pancreatic enzymes has been studied in isolated pancreatic acini from sham-operated, castrated, and adrenalectomized animals as well as in animals that have been both adrenalectomized and castrated. Protein synthesis was measured by pulse labeling of acini with [35S]methionine followed by either trichloroacetic acid precipitation of total protein and counting or by SDS-PAGE and autoradiography, and additionally by in vitro translation of extracted pancreatic RNA using rabbit reticulocytes. Adrenalectomy resulted in a 70% reduction of amylase activity per milligram of acinar protein as a result of a decrease in amylase synthesis. This reduction in amylase synthesis is a consequence of a decrease in the amount of mRNA coding for amylase. After adrenalectomy, plasma concentrations of the following were reduced compared to controls: corticosterone to 0.45%, insulin to 11%, and glucose to approximately 66%. Addition of glucose to the drinking water caused an increase in insulin and plasma glucose, but this was not followed by an increase in amylase activity. We postulate that corticosterone directly regulates amylase synthesis in the rat pancreas.
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PMID:Role of glucocorticosteroids in the regulation of pancreatic amylase synthesis. 247 63

Circulating insulin-like growth factor binding protein (IGF BP) activity is increased in animals with streptozotocin-induced diabetes. Separation of BPs by SDS/PAGE for ligand and immunoblot analysis revealed that a 32,000 molecular weight BP is present and increased in diabetic serum. This BP is immunologically distinct from the low molecular weight fetal rat BP (rBP2) and is related to the human amniotic fluid BP (hBP1) that is increased in patients with insulin dependent diabetes mellitus.
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PMID:Identification of a type 1 insulin-like growth factor binding protein (IGF BP) in serum from rats with diabetes mellitus. 247 84

In order to investigate the early renal damage in diabetes mellitus, 89 diabetics without proteinuria by dipsticks and 67 normal control subjects were examined by means of SDS-PAGE. The relationships between electrophoretic patterns of urinary protein and duration of diabetes, age of patients, metabolic controls and stages of retinopathy were examined. 1) The percentage of higher molecular weight (MW) proteins (67,000 less than or equal to MW) was larger in diabetics than that in controls. Especially the percentage of proteins with MW between 67,000 and 94,000, which include transferrin was 13.9 +/- 6.9% in diabetics, significantly higher than that in controls (10.3 +/- 5.1%) (P less than 0.01). On the contrary, the percentage of low MW proteins (MW less than 67,000) was relatively small in diabetics. 2) The excretion of higher MW proteins increased until 16 years of diabetic duration, however that decreased after 16 years. Especially in the group with duration longer than 20 years, excretion of low MW proteins increased. 3) Electrophoretic patterns of urinary proteins in patients with good metabolic control were similar to those in normal controls. 4) Excretion of higher MW proteins increased in patients with retinopathic complication suggesting the progression to microangiopathy. From the above results, we concluded that increased excretion of higher MW proteins in diabetics may be the results of GBM damages in protein selectivity. In patients with longer history of diabetes, predominant excretion of urinary low MW proteins may be the result of tubular dysfunction due to macroangiopathy.
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PMID:[A study of microproteinuria in patients with diabetes mellitus]. 259 18

We describe 3 patients affected by Pearson's syndrome, presenting anemia, exocrine pancreas failure, and skeletal abnormalities; insulin-dependent diabetes mellitus arose in two cases during the course of the disease. Bone marrow dysplasia and exocrine pancreas failure are also reported in Shwachman's syndrome; the two forms differ in bone marrow morphology. The clinical pattern of Pearson's syndrome can be so polymorphic as to increase the difficulties of differential diagnosis with Shwachman's syndrome.
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PMID:New clinical aspects of Pearson's syndrome. Report of three cases. 262 42

The specific activities of membrane-bound maltase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) in isolated brush border membranes (BBMs) of alloxan-induced diabetic, glucose-infused and maltose-infused rabbits were 30%, 140% and 160%, respectively, of those of control rabbits. Differences in the relative activities of trehalase (EC 3.2.1.28), another disaccharidase, in these groups were similar but less marked. However, the activities of two other marker enzymes of the brush border, alkaline-phosphatase and gamma-glutamyl transpeptidase, were similar in the 4 groups of rabbits. The decreases in the activities of the two disaccharidases were due to changes in the Vmax values of the enzymes without change in their Km values for maltose and trehalose. The maltase activities in the 4 groups showed similar dependences on Tris-HCl, KCl and NaCl. The electrophoretic profiles of the BBMs of the 4 groups on SDS-polyacrylamide gel showed slight differences. From these results, we conclude that diabetes, glucose infusion and maltose infusion probably change the concentrations of active enzymes in the BBM of the kidney in rabbits.
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PMID:Comparisons of maltase activities in kidney brush border membranes from normal, diabetic, glucose-infused and maltose-infused rabbits. 266 45

The discovery of a cold-labile cytosolic acetyl-CoA hydrolase of high activity in rat liver by Prass et al. [(1980) J. Biol. Chem. 255, 5215-5223] has questioned the importance of mitochondrial acetyl-CoA hydrolase for the formation of free acetate [Grigat et al. (1979) Biochem. J. 177, 71-79] under physiological conditions. Therefore this problem has been reevaluated by comparing various properties of the two enzymes. Cold-labile cytosolic acetyl-CoA hydrolase bands with an apparent Mr of 68000 during SDS/polyacrylamide gel electrophoresis, while the native enzyme elutes in two peaks with apparent Mr of 136000 and 245000 during gel chromatography in the presence of 2 mM ATP. The mitochondrial enzyme elutes under the same conditions with an apparent Mr of 157000. Under conditions where the cold-labile enzyme binds strongly to DEAE-Bio-Gel and ATP-agarose, the mitochondrial enzyme remains unbound. The cold-labile enzyme can be activated 14-fold by ATP, half-maximal activation occurring already at 40 microM ATP. AdoPP[NH]P, AdoPP[CH2]P and GTP have a similar though weaker effect. ADP as well as GDP can completely inhibit the cold-labile enzyme with 50% inhibition occurring for both nucleotides at about 1.45 microM. The binding of ATP and ADP is competitive. Acetyl phosphate and pyrophosphate have no effect on the activity of the cold-labile enzyme. The mitochondrial acetyl-CoA hydrolase is not affected by these nucleotides. CoASH is a strong product inhibitor (approximately equal to 80% inhibition at 40 microM CoASH) of the cold-labile enzyme, but only a weak inhibitor of the mitochondrial enzyme. Under in vivo conditions the activity of the cold-labile cytosolic acetyl-CoA hydrolase can be no more than 7% of the activity calculated for mitochondrial acetyl-CoA hydrolase under the same conditions. Accordingly the mitochondrial enzyme seems to be mainly responsible for the formation of free acetate by the intact liver, especially in view of the fact that the substrate specificity of the mitochondrial enzyme is much higher (activity ratios acetyl-CoA/butyryl-CoA 4.99 and 1.16 for the mitochondrial and the cold-labile enzyme respectively). Alloxan diabetes neither increased the activity of the cold-labile enzyme nor that of the mitochondrial enzyme. No experimental support has been found yet for the hypothesis that the acetyl-CoA hydrolase activity of the cold-labile enzyme represents the side-activity of an acetyl-transferase.
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PMID:On the regulation of cold-labile cytosolic and of mitochondrial acetyl-CoA hydrolase in rat liver. 285 46

Investigations were carried out to clarify the role of autoimmune phenomena in the pathogenesis of cataract in the adult human lens. Studies were carried out to determine the presence of serum antibodies to lens protein in patients with senile cataract, in patients with diabetes mellitus with and without cataract, and in healthy adult controls using the interfacial test and the gel-diffusion technique. Non-specific antibodies were removed by adsorption of sera with homogenized rat liver. A high proportion of healthy adults was found to have anti-lens protein antibodies (44.4% by the gel-diffusion method). In contrast, patients with cataract and diabetic patients with no cataract demonstrated double this incidence (82% and 80%), while all diabetic patients with cataract showed the presence of antibodies (P = 0.0002). The possible causes for the development of lens antibodies in normal healthy humans are discussed. Also, the causes for the higher incidence of lens antibodies in patients with cataract and in diabetic subjects with no clinical evidence of cataract are considered in relation to cataract formation. Homogenates of cataractous lenses when investigated revealed the presence of both IgG and IgM immunoglobulins, the former probably to a greater extent. Fluorescent microscopy on cryosections of senile and diabetic cataractous lenses revealed the presence of immunoglobulins within the lens. The antigen in the immune complexes isolated from homogenized cataractous lenses was characterized by the SDS-polyacrylamide gel electrophoresis method. A single band was consistently obtained and the molecular weight of the protein was estimated to be between 35,000 and 40,000. The strong possibility of auto-antibodies to lens protein being of aetiological significance in the pathogenesis of cataract is discussed.
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PMID:The role of autoimmune phenomena in the pathogenesis of cataract. 311 83

Removal of insulin from the peritubular vessels involves binding of insulin to specific receptors in the basolateral membranes (BLM); this is followed by phosphorylation of the receptor which may mediate the actions of the hormone. In most tissues receptor number is regulated by plasma insulin levels and is increased in insulinopenic diabetics. To determine whether cortical BLM insulin receptors are similarly regulated, we studied insulin binding to receptors in BLM from normal control rats and rats with streptozotocin diabetes of varying severity. Specific binding of insulin did not differ between control and modestly insulinopenic diabetics but was increased significantly in the severely insulinopenic diabetics. Insulin treatment returned binding to normal. Scatchard analysis suggested an increase in the binding capacity of the severe diabetic BLM rather than an increase in affinity for insulin. This latter was confirmed by competitive experiments in which similar displacement curves were obtained with control and diabetic membranes. Insulin removed by glomerular filtration binds to specific receptors in the luminal membranes but unlike BLM receptors, phosphorylation of these luminal receptors has not been observed. To determine whether luminal and BLM receptors differ structurally, binding sites in both membranes were affinity labelled with 125I-insulin and the cross linking agent, disuccinimidyl suberate, and subjected to SDS-polyacrylamide gel electrophoresis in the presence of a reducing agent. Autoradiograms revealed that the major specifically labelled subunit in both membranes is a 135,000 Mr species which is more abundant in the BLM. We conclude that insulin receptors in cortical BLM respond to severe insulinopenic diabetes as do receptors in most other tissues.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of experimental diabetes on insulin binding by renal basolateral membranes. 353 45

The ratio of type-III to type-I collagen is measured in human conjunctival biopsies from control and diabetic subjects. The tissue is digested by CNBr and the resulting peptides are quantified by SDS polyacrylamide gel electrophoresis. The peptides used are alpha 1-(I)CB7 and alpha 1-(III)CB8. In control population, of type-III collagen slightly increases with age. In two diabetic populations, (juvenile onset diabetes and maturity onset diabetes), the percentage of type-III collagen is significantly higher than in age-matched control groups. These data plus those previously obtained on genetically diabetic mice indicate that diabetes mellitus affects the expression of interstitial collagen phenotype. Preliminary results on prediabetic subjects suggest the role of genetic factors in such alterations.
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PMID:Increased type-III/type-I collagen ratios in diabetic human conjunctival biopsies. 369 69

To identify the mechanisms responsible for the paucity of recently synthesized collagen in connective tissues during diabetes, in vitro procollagen metabolism was studied in non-diabetic (control) and diabetic rats. Achilles tendons from the two groups were incubated for 1-8 h (35 degrees C) in medium containing [14C]proline and the radiolabeled collagen in the tissue, and that released into the media, were examined by SDS-polyacrylamide gel electrophoresis and fluorography. The bulk of the radiolabeled collagen in tendon from the diabetics was recovered as degradation products; these, but also procollagen and collagen components, were prominent in the control tissues. Moreover, the collagenous components synthesized by the diabetic rat tendons were more readily digested in vitro by trypsin than those produced by control tissues. We conclude that diabetes reduces collagen accretion in connective tissues in part due to increased intracellular degradation of procollagen.
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PMID:Diabetes stimulates procollagen degradation in rat tendon in vitro. 394 86


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