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  • 1995-1999  (5)
  • Non-insulin-dependent diabetes mellitus  (2)
  • epidemiology  (2)
  • islets  (2)
  • 1
    ISSN: 1432-0428
    Schlagwort(e): Key words Non-insulin-dependent diabetes mellitus ; insulin ; sulphonylurea receptors ; islets ; glibenclamide ; secretory granule.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Sulphonylureas stimulate insulin secretion by binding to a receptor in the pancreatic beta-cell plasma membrane resulting in inhibition of ATP-sensitive K+ channels, membrane depolarization and thus influx of Ca2+ through voltage-dependent Ca2+ channels. Sulphonylureas can also induce hormone release at fixed membrane potentials without Ca2+ entry suggesting that these drugs may have other modes of action. We have determined whether different forms of sulphonylurea-binding proteins are present in insulin-secreting cells and their subcellular localization by density gradient centrifugation. Binding studies using [3H]-glibenclamide showed that islet and insulinoma membranes contained a single high affinity sulphonylurea binding site (Kd = 1 nmol/l). Photo-crosslinking of the drug to the membranes resulted in labelling of two proteins with apparent molecular weights of 170 and 140 kDa. The same analyses of insulinoma subcellular fractions showed that the majority ( 〉 90 %) of binding proteins were localized to intracellular membranes with only minor levels ( 〈 10 %) on plasma membranes. The 170 kDa sulphonylurea binding protein was present in both plasma and granule membrane fractions whereas the 140 kDa form was not present in the plasma membrane fraction. The differences in the molecular forms and subcellular distribution of the receptor are consistent with sulphonylureas having multiple sites of action in the pancreatic beta cell. [Diabetologia (1995) 38: 277–282]
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1432-0428
    Schlagwort(e): Non-insulin-dependent diabetes mellitus ; insulin ; sulphonylurea receptors ; islets ; glibenclamide ; secretory granule
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Sulphonylureas stimulate insulin secretion by binding to a receptor in the pancreatic beta-cell plasma membrane resulting in inhibition of ATP-sensitive K+ channels, membrane depolarization and thus influx of Ca2+ through voltage-dependent Ca2+ channels. Sulphonylureas can also induce hormone release at fixed membrane potentials without Ca2+ entry suggesting that these drugs may have other modes of action. We have determined whether different forms of sulphonylurea-binding proteins are present in insulin-secreting cells and their subcellular localization by density gradient centrifugation. Binding studies using [3H]-glibenclamide showed that islet and insulinoma membranes contained a single high affinity sulphonylurea binding site (Kd = 1 nmol/l). Photo-crosslinking of the drug to the membranes resulted in labelling of two proteins with apparent molecular weights of 170 and 140 kDa. The same analyses of insulinoma subcellular fractions showed that the majority (〉90%) of binding proteins were localized to intracellular membranes with only minor levels (〈10%) on plasma membranes. The 170 kDa sulphonylurea binding protein was present in both plasma and granule membrane fractions whereas the 140 kDa form was not present in the plasma membrane fraction. The differences in the molecular forms and subcellular distribution of the receptor are consistent with sulphonylureas having multiple sites of action in the pancreatic beta cell.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1432-0428
    Schlagwort(e): Key words Proinsulin ; insulin ; insulin secretion ; non-insulin-dependent diabetes mellitus ; epidemiology ; follow-up study.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Insulin resistance and impaired insulin secretion are thought to be the primary defects in the pathogenesis of non-insulin-dependent diabetes mellitus (NIDDM). Disproportionately increased proinsulin relative to insulin levels are suggested to be an early indicator of a failing pancreas. We examined the relationship of fasting specific insulin, proinsulin, and 32, 33 split proinsulin concentrations, and the proinsulin: insulin ratio to the risk of developing NIDDM 3.5 years later in 65–74-year-old non-diabetic Finnish subjects participating in a population-based study (n = 892) on diabetes and heart disease. Altogether 69 subjects developed NIDDM over a 3.5-year follow-up (cases). The cases were compared to randomly-selected gender-matched control subjects (n = 69) and control subjects matched for gender, glucose tolerance status (normal or impaired), and body mass index (n = 69). There were no differences in insulin concentrations between cases and random or matched control subjects [median and interquartile range; 123 (77–154), 108 (74–143), 118 (83–145) pmol/l, p = 0.271]. Random control subjects had lower proinsulin and 32,33 split proinsulin concentrations and split proinsulin: insulin ratios compared to cases [5.7 (3.8–9.0) vs 7.3 (4.8–10.0) pmol/l, p = 0.005; 7.3 (4.5–13.0) vs 10.4 (7.1–18.0) pmol/l, p = 0.002; 0.073 (0.057–0.110) vs 0.097 (0.060–0.135), p = 0.003]. Matched control subjects had lower proinsulin concentrations and proinsulin: insulin ratios compared to cases [5.9 (4.0–7.7) vs 7.3 (4.8–10.0) pmol/l, p = 0.019; 0.048 (0.035–0.071) vs 0.064 (0.045–0.100), p = 0.008]. When cases were compared to matched control subjects a 1 SD increase in baseline proinsulin: insulin ratio was associated with a 1.37-fold risk (p = 0.020) of developing diabetes. Moreover, this association was independent of fasting glucose concentration at baseline. Thus, in elderly prediabetic subjects disproportionately increased proinsulin concentration, an indicator of defective insulin secretion, is associated with conversion to diabetes over a short time period. [Diabetologia (1995) 38: 1176–1182]
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1432-0428
    Schlagwort(e): Proinsulin ; insulin ; insulin secretion ; non-insulin-dependent diabetes mellitus ; epidemiology ; follow-up study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Insulin resistance and impaired insulin secretion are thought to be the primary defects in the pathogenesis of non-insulin-dependent diabetes mellitus (NIDDM). Disproportionately increased proinsulin relative to insulin levels are suggested to be an early indicator of a failing pancreas. We examined the relationship of fasting specific insulin, proinsulin, and 32, 33 split proinsulin concentrations, and the proinsulin: insulin ratio to the risk of developing NIDDM 3.5 years later in 65–74-year-old non-diabetic Finnish subjects participating in a populationbased study (n=892) on diabetes and heart disease. Altogether 69 subjects developed NIDDM over a 3.5-year follow-up (cases). The cases were compared to randomly-selected gender-matched control subjects (n=69) and control subjects matched for gender, glucose tolerance status (normal or impaired), and body mass index (n=69). There were no differences in insulin concentrations between cases and random or matched control subjects [median and interquartile range; 123 (77–154), 108 (74–143), 118 (83–145) pmol/l, p=0.271]. Random control subjects had lower proinsulin and 32,33 split proinsulin concentrations and split proinsulin: insulin ratios compared to cases [5.7 (3.8–9.0) vs 7.3 (4.8–10.0) pmol/l, p=0.005; 7.3 (4.5–13.0) vs 10.4 (7.1–18.0) pmol/l, p=0.002; 0.073 (0.057–0.110) vs 0.097 (0.060–0.135), p=0.003]. Matched control subjects had lower proinsulin concentrations and proinsulin: insulin ratios compared to cases [5.9 (4.0–7.7) vs 7.3 (4.8–10.0) pmol/l, p=0.019; 0.048 (0.035–0.071) vs 0.064 (0.045–0.100), p=0.008]. When cases were compared to matched control subjects a 1 SD increase in baseline proinsulin: insulin ratio was associated with a 1.37-fold risk (p=0.020) of developing diabetes. Moreover, this association was independent of fasting glucose concentration at baseline. Thus, in elderly prediabetic subjects disproportionately increased proinsulin concentration, an indicator of defective insulin secretion, is associated with conversion to diabetes over a short time period.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1432-0428
    Schlagwort(e): Non-insulin-dependent diabetes mellitus ; vitamin D ; vitamin D deficiency ; total insulin ; specific insulin ; proinsulin ; 32,33 split proinsulin ; C-peptide ; glucose intolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Vitamin D deficiency reduces insulin secretion and still occurs in East London Asians in whom the prevalence of diabetes mellitus is at least four times that of Caucasians. Vitamin D status was assessed in 44 of 65 non-diabetic subjects ‘at risk’ of diabetes (spot blood glucose level 〉6.0 mmol/l 〈2 h post cibum, or 〉4.6 mmol/l 〉2 h post cibum on two separate occasions) and in 15 of 60 age and sex-matched ‘low-risk’ control subjects who attended for oral glucose tolerance test (OGTT) after screening of 877 omnivorous subjects not known to have diabetes. It was found that 95% of at-risk and 80% of low-risk subjects were vitamin D deficient (serum 25-hydroxy-vitamin D 〈11 ng/ml). Diabetes was present in 16, impaired glucose tolerance in 12 and normoglycaemia in 19 at-risk subjects, impaired glucose tolerance in 2, and normoglycaemia in 13 low-risk subjects. Correlations of 30-min OGTT blood glucose, specific insulin and C-peptide levels with 25-hydroxy-vitamin D concentrations in 44 at-risk subjects were −0.31 (p=0.04), 0.59 (p=0.0001) and 0.44 (p=0.006). In 15 ‘not-at-risk’ subjects 30-min OGTT specific insulin and C-peptide levels correlated with 25-hydroxy-vitamin D, r=0.39 (p=0.04) and 0.16 (p=0.43), respectively. Serum alkaline phosphatase concentration was higher in at-risk than not-at-risk subjects (59.6 vs 46.5 IU/l, p=0.012); corrected calcium concentrations were comparable (2.38 vs 2.39 mmol/l, p=0.7). Following treatment with 100,000 IU vitamin D by i.m. injection, specific insulin, C-peptide [30 min on OGTT] and 25-hydroxy-vitamin D concentrations had risen 8–12 weeks later [means±SD] from 57±62 to 96.2±82.4 mU/l [p=0.0017], 1.0±0.4 to 1.7±0.8 pmol/ml [p=0.0001] and 3.6±1.8 to 13.5±7.4 ng/ml [p=0.0001], (but not to low-risk group values of 179±89 mU/l, 2.7±1.14 pmol/ml and 8.16±6.4 ng/ml), respectively. Both total serum alkaline phosphatase and corrected calcium concentrations rose following vitamin D treatment in the at-risk subjects by 11.1±8.22 (from 44 to 55 IU/l) and 0.15±0.18, (2.43 to 2.57 mmol/l), respectively (p=0.004). Abnormal glucose tolerance was unchanged by vitamin D treatment. The value of early and sustained repletion with vitamin D in diabetes prophylaxis should be examined in communities where vitamin D depletion is common.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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