Persistent impairment of the insulin response to glucose both in vivo and in vitro after streptozotocin exposure: Studies with grafted pancreatic islets and islets maintained in culture

1989 ◽  
Vol 121 (6) ◽  
pp. 849-856 ◽  
Author(s):  
Décio L. Eizirik ◽  
Stellan Sandler ◽  
Olle Korsgren ◽  
Leif Jansson ◽  
Arne Andersson
Keyword(s):  
Pancreatic Islets ◽  
Insulin Release ◽  
Common Property ◽  
Insulin Response ◽  
Insulin Content ◽  
Functional Responses ◽  
Mouse Pancreatic Islets ◽  
Insulin Response To Glucose

Abstract. The functional responses of the pancreatic B-cells after cytotoxic damage are still largely unknown. Using in vitro models to clarify this issue, we have recently observed a preferential reduction of glucose-stimulated insulin production and release in mouse pancreatic islets maintained in culture after in vitro exposure to streptozotocin. In order to evaluate the relevance of these findings in vivo, two sets of experiments were performed. First, mouse pancreatic islets were exposed in vitro to 2.2 mmol/l streptozotocin or vehicle alone, cultured for 6 days, and finally grafted under the kidney capsule of normoglycemic nude mice. Two weeks after transplantation there was no difference in the total DNA and insulin content between the two groups of islet grafts, but the insulin concentration, as expressed per μg DNA, was decreased by 40% in the streptozotocin-treated islets. The insulin release of the grafts, during perfusion of the graft-bearing kidney in situ with 16.7 mmol/l glucose was diminished in the streptozotocin group, whilst perfusion with 16.7 mmol/l glucose plus 5 mmol/l theophylline was able partially to counteract the reduction in insulin release. In the second set of experiments, NMRI mice were injected iv with 160 mg/kg streptozotocin or vehicle alone, and their islets isolated 15 min after the injections. After 6 days in culture, there was no decrease in DNA, glucagon and somatostatin contents, but the insulin content was decreased by 40% in the streptozotocin exposed islets. These islets also showed a 60% decrease in the insulin response to glucose, which was partly counteracted by incubation with 16.7 mmol/1 glucose plus 5 mmol/l theophylline. These observations suggest that a defective response to glucose, in conjunction with a better response to non-nutrient secretagogues, may be a common property of pancreatic islets following toxin-induced disturbances.

Effects of starvation on oxidative metabolism and insulin release by isolated mouse pancreatic islets

1982 ◽  
Vol 101 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Michael Welsh ◽  
Arne Andersson
Keyword(s):  
Pancreatic Islets ◽  
Insulin Release ◽  
Oxidative Metabolism ◽  
Oxidation Rate ◽  
Insulin Response ◽  
Leucine Oxidation ◽  
Oxidation Rates ◽  
Impaired Insulin ◽  
Mouse Pancreatic Islets ◽  
Insulin Response To Glucose

Abstract. Pancreatic islets were isolated from either 60-h-starved or fed mice and subsequently incubated in order to determine the insulin release in response to various secretagogues, rates of glucose, leucine or glutamine oxidation or the acetoacetate production from leucine. It was found that in contrast to findings with islets isolated from fed mice 16.7 mm glucose, 10 mM leucine and 10 mm α-ketoisocaproic acid did not stimulate the insulin release of islets isolated from starved mice. Moreover, the insulin release in response to leucine plus glutamine or glucose plus glutamine was decreased after starvation although these values were higher than those obtained for glutamine addition alone. Theophylline, however, restored partly the impaired insulin response to glucose and completely that to leucine or α-ketoisocaproic acid. Starvation was found to inhibit the islet glucose oxidation rate but the addition of theophylline was without effect irrespective of whether the islets were prepared from fed or starved mice. On the contrary, islet leucine oxidation was increased after starvation and again theophylline did not affect the islet leucine oxidation rate. Likewise, the islet acetoacetate production was increased after starvation. The glutamine oxidation rates were not affected by starvation, either when tested alone or together with glucose or leucine. It is concluded that although the starvation-induced impairment of glucose-stimulated insulin release may well be explained by an influence on the oxidative metabolism other factors are also involved as regards leucine-stimulated insulin release.

Glucagon-like peptide-1(7-36)-amide confers glucose sensitivity to previously glucose-incompetent beta-cells in diabetic rats: in vivo and in vitro studies

1997 ◽  
Vol 155 (2) ◽  
pp. 369-376 ◽  
Author(s):  
N Dachicourt ◽  
P Serradas ◽  
D Bailbe ◽  
M Kergoat ◽  
L Doare ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Beta Cells ◽  
Insulin Release ◽  
Insulin Response ◽  
Diabetic Rats ◽  
Insulin Response To Glucose ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

The effects of glucagon-like peptide-1(7-36)-amide (GLP-1) on cAMP content and insulin release were studied in islets isolated from diabetic rats (n0-STZ model) which exhibited impaired glucose-induced insulin release. We first examined the possibility of re-activating the insulin response to glucose in the beta-cells of the diabetic rats using GLP-1 in vitro. In static incubation experiments, GLP-1 amplified cAMP accumulation (by 170%) and glucose-induced insulin release (by 140%) in the diabetic islets to the same extent as in control islets. Using a perifusion procedure, GLP-1 amplified the insulin response to 16.7 mM glucose by diabetic islets and generated a clear biphasic pattern of insulin release. The incremental insulin response to glucose in the presence of GLP-1, although lower than corresponding control values (1.56 +/- 0.37 and 4.53 +/- 0.60 pg/min per ng islet DNA in diabetic and control islets respectively), became similar to that of control islets exposed to 16.7 mM glucose alone (1.09 +/- 0.15 pg/min per ng islet DNA). Since in vitro GLP-1 was found to exert positive effects on the glucose competence of the residual beta-cells in the n0-STZ model. we investigated the therapeutic effect of in vivo GLP-1 administration on glucose tolerance and glucose-induced insulin release by n0-STZ rats. An infusion of GLP-1 (10 ng/min per kg; i.v.) in n0-STZ rats enhanced significantly (P < 0.01) basal plasma insulin levels, and, when combined with an i.v. glucose tolerance and insulin secretion test, it was found to improve (P < 0.05) glucose tolerance and the insulinogenic index, as compared with the respective values of these parameters before GLP-1 treatment.

Rapid depletion of somatostatin in isolated mouse pancreatic islets after treatment with cysteamine

1985 ◽  
Vol 110 (2) ◽  
pp. 227-231 ◽  
Author(s):  
Birger Petersson ◽  
Claes Hellerström
Keyword(s):  
Pancreatic Islets ◽  
Insulin Release ◽  
Basal Insulin ◽  
Glucose Stimulation ◽  
Isolated Pancreatic Islets ◽  
Basal Release ◽  
Mouse Pancreatic Islets ◽  
Mouse Islets

Abstract. Cysteamine (CSH; β-mercaptoethylamine) is known to deplete pancreatic somatostatin without affecting the insulin or glucagon content. It may therefore be useful for studies of intra-islet regulation of hormone release. In the present study injection of CSH (60 mg/kg body weight) to mice decreased the somatostatin content of their isolated pancreatic islets to 50% in 1 h and 30% in 4 h as compared to islets of non-injected controls. Exposure of isolated mouse islets to CSH (100 μg/ml) for either 0.5 h followed by incubation in control medium for 3.5 h, or continuously for 4 h, decreased the somatostatin content to about 40% of the controls. There was no change in the islet content of insulin or glucagon. Islets pretreated with CSH (100 μg/ml) for 1 h in vitro showed a decreased glucose stimulation of both oxygen consumption and glucose oxidation. Measurements of insulin release after a similar preincubation of the islets indicated an increased basal release and an attenuated glucose stimulation. It is concluded that CSH rapidly decreases islet somatostatin both in vivo and in vitro. This depletion may lead to a loss of tonic inhibition by islet somatostatin on basal insulin release. It is, however, more plausible that the increased basal insulin release reflected a direct effect of CSH on the islet β-cells.

scholarly journals Disruption of the Dopamine D2 Receptor Impairs Insulin Secretion and Causes Glucose Intolerance

Endocrinology ◽  
2010 ◽  
Vol 151 (4) ◽  
pp. 1441-1450 ◽  
Author(s):  
Isabel García-Tornadú ◽  
Ana M. Ornstein ◽  
Astrid Chamson-Reig ◽  
Michael B. Wheeler ◽  
David J. Hill ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Intolerance ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
Insulin Response ◽  
Wild Type ◽  
Β Cell ◽  
Insulin Response To Glucose

The relationship between antidopaminergic drugs and glucose has not been extensively studied, even though chronic neuroleptic treatment causes hyperinsulinemia in normal subjects or is associated with diabetes in psychiatric patients. We sought to evaluate dopamine D2 receptor (D2R) participation in pancreatic function. Glucose homeostasis was studied in D2R knockout mice (Drd2−/−) mice and in isolated islets from wild-type and Drd2−/− mice, using different pharmacological tools. Pancreas immunohistochemistry was performed. Drd2−/− male mice exhibited an impairment of insulin response to glucose and high fasting glucose levels and were glucose intolerant. Glucose intolerance resulted from a blunted insulin secretory response, rather than insulin resistance, as shown by glucose-stimulated insulin secretion tests (GSIS) in vivo and in vitro and by a conserved insulin tolerance test in vivo. On the other hand, short-term treatment with cabergoline, a dopamine agonist, resulted in glucose intolerance and decreased insulin response to glucose in wild-type but not in Drd2−/− mice; this effect was partially prevented by haloperidol, a D2R antagonist. In vitro results indicated that GSIS was impaired in islets from Drd2−/− mice and that only in wild-type islets did dopamine inhibit GSIS, an effect that was blocked by a D2R but not a D1R antagonist. Finally, immunohistochemistry showed a diminished pancreatic β-cell mass in Drd2−/− mice and decreased β-cell replication in 2-month-old Drd2−/− mice. Pancreatic D2Rs inhibit glucose-stimulated insulin release. Lack of dopaminergic inhibition throughout development may exert a gradual deteriorating effect on insulin homeostasis, so that eventually glucose intolerance develops.

scholarly journals Islet constitutive nitric oxide synthase and glucose regulation of insulin release in mice

1999 ◽  
Vol 163 (1) ◽  
pp. 39-48 ◽  
Author(s):  
B Akesson ◽  
R Henningsson ◽  
A Salehi ◽  
I Lundquist
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Insulin Release ◽  
Ex Vivo ◽  
Insulin Response ◽  
Glucose Regulation ◽  
Nos Inhibitor ◽  
Oxide Synthase

We have studied, by a combined in vitro and in vivo approach, the relation between the inhibitory action of N(G)-nitro-l-arginine methyl ester (L-NAME), a selective inhibitor of nitric oxide synthase (NOS), on the activity of islet constitutive NOS (cNOS) and glucose regulation of islet hormone release in mice. The cNOS activity in islets incubated in vitro at 20 mM glucose was not appreciably affected by 0.05 or 0.5 mM L-NAME, but was greatly suppressed (-60%) by 5 mM L-NAME. Similarly, glucose-stimulated insulin release was unaffected by the lower concentrations of L-NAME but greatly enhanced in the presence of 5 mM of the NOS inhibitor. In incubated islets inhibition of cNOS activity resulted in a modestly enhanced insulin release in the absence of glucose, did not display any effect at physiological or subphysiological glucose concentrations, but resulted in a markedly potentiated insulin release at hyperglycaemic glucose concentrations. In the absence of glucose, glucagon secretion was suppressed by L-NAME. The dynamics of glucose-induced insulin release and (45)Ca(2+) efflux from perifused islets revealed that L-NAME caused an immediate potentiation of insulin release, and a slight increase in (45)Ca(2+) efflux. In islets depolarized with 30 mM K(+) in the presence of the K(+)(ATP) channel opener, diazoxide, L-NAME still greatly potentiated glucose-induced insulin release. Finally, an i.v. injection of glucose to mice pretreated with L-NAME was followed by a markedly potentiated insulin response, and an improved glucose tolerance. In accordance, islets isolated directly ex vivo after L-NAME injection displayed a markedly reduced cNOS activity. In conclusion, we have shown here, for the first time, that biochemically verified suppression of islet cNOS activity, induced by the NOS inhibitor L-NAME, is accompanied by a marked potentiation of glucose-stimulated insulin release both in vitro and in vivo. The major action of NO to inhibit glucose-induced insulin release is probably not primarily linked to changes in Ca(2+) fluxes and is exerted mainly independently of membrane depolarization events.

scholarly journals Die ultrastrukturele, morfometriese evaluering van die mikrotubulere stelsel in gestimuleerde B-selle van die pankreas

1992 ◽  
Vol 11 (4) ◽  
pp. 127-135
Author(s):  
A. Crous ◽  
A. M. De Beer ◽  
E. J. Visser
Keyword(s):  
B Cells ◽  
Insulin Release ◽  
Insulin Response ◽  
High Magnification ◽  
Tissue Samples ◽  
Islet Tissue ◽  
Pancreatic B Cells ◽  
Complete Cell

The intracellular distribution of microtubules in pancreatic B-cells was studied morphometrically to elucidate the positive correlation between microtubular content and the rate of insulin release found by biochemical investigations. Rat islet tissue was glucose stimulated under in vivo and in vitro (isolated islets) conditions and tissue samples taken to represent both phases of the phasic insulin response. Electron micrographs (x40 000) of individual B-cells were assembled into montages to obtain complete cell profiles at high magnification.

Sustained exposure of toxically damaged mouse pancreatic islets to high glucose does not increase β-cell dysfunction

1989 ◽  
Vol 123 (1) ◽  
pp. 47-51 ◽  
Author(s):  
D. L. Eizirik ◽  
S. Sandler
Keyword(s):  
Pancreatic Islets ◽  
Insulin Release ◽  
High Glucose ◽  
Β Cells ◽  
Β Cell ◽  
Glucose Stimulation ◽  
Cell Dysfunction ◽  
Mouse Pancreatic Islets ◽  
Insulin Secretory Response

ABSTRACT The aim of this study was to clarify whether prolonged in-vitro exposure of either normal or damaged β cells to a high glucose environment can be toxic to these cells. For this purpose NMRI mice were injected intravenously with a diabetogenic dose of streptozotocin (SZ; 160 mg/kg) or vehicle alone (controls). Their islets were isolated 15 min after the injection and subsequently maintained in culture for 21 days in the presence of 11·1 or 28 mmol glucose/l. After this period, during acute glucose stimulation, the control islets showed a marked increase in their insulin release in response to a high glucose stimulus. In the SZ-exposed islets there was a decrease in DNA and insulin contents, and a deficient insulin secretory response to glucose. However, in the SZ-damaged islets as well as in the control islets, culture with 28 mmol glucose/l compared with 11·1 mmol glucose/l did not impair islet retrieval after culture, islet DNA content or glucose-induced insulin release. Thus, the degree of damage was similar in the SZ-treated islets cultured at the two concentrations of glucose. These results suggest that glucose is not toxic to normal or damaged mouse pancreatic islets over a prolonged period in tissue culture. Journal of Endocrinology (1989) 123, 47–51

Glucocorticoid increases glucose cycling and inhibits insulin release in pancreatic islets of ob/ob mice

1992 ◽  
Vol 263 (4) ◽  
pp. E663-E666 ◽  
Author(s):  
A. Khan ◽  
C. G. Ostenson ◽  
P. O. Berggren ◽  
S. Efendic
Keyword(s):  
Pancreatic Islets ◽  
Insulin Release ◽  
Glucose Oxidation ◽  
Insulin Response ◽  
Dexamethasone Treatment ◽  
Short Term ◽  
Glucose Flux ◽  
Glucose Incorporation ◽  
Insulin Response To Glucose ◽  
Insulin Responsiveness

Normoglycemic ob/ob mice were treated for 24 or 48 h with either 25 micrograms/day of dexamethasone or saline. After an overnight fast, the animals were killed and pancreatic islets were incubated with 3H2O or [U-14C]glucose or [5-3H]glucose at 5.5 and 16.7 mM glucose. Incorporation of 3H from 3H2O into carbon 2 of medium glucose and the yield of 14CO2 from [U-14C]glucose and 3H2O from [5-3H]glucose were measured. Dexamethasone treatment for 48 h significantly increased the rate of dephosphorylation of glucose in islets both at 5.5 mM (24 vs. 16%) and 16.7 mM (56 vs. 36%) glucose, whereas glucose oxidation and utilization were unaffected. Dexamethasone treatment also inhibited insulin release by approximately 60% at 5.5 and 16.7 mM glucose, either in the presence or absence of 10 mM arginine, but had no effect when insulin release was stimulated by 1 mM 3-isobutyl-1-methylxanthine. Moreover, 24-h treatment with dexamethasone significantly increased glucose cycling at low and high glucose concentrations in the medium and inhibited insulin responsiveness to glucose and arginine. In conclusion, short-term dexamethasone treatment increases glucose flux through glucose-6-phosphatase in islets from ob/ob mice. This effect may contribute to the decreased insulin response to glucose and arginine found in animals treated with dexamethasone.

scholarly journals The pentose cycle and insulin release in mouse pancreatic islets

1972 ◽  
Vol 126 (3) ◽  
pp. 525-532 ◽  
Author(s):  
S. J. H. Ashcroft ◽  
L. C. C. Weerasinghe ◽  
J. M. Bassett ◽  
P. J. Randle
Keyword(s):  
Glucose Metabolism ◽  
Pancreatic Islets ◽  
Insulin Release ◽  
Glucose Concentration ◽  
Glucose Utilization ◽  
Fold Increase ◽  
Primary Role ◽  
Mouse Pancreatic Islets ◽  
Oxidation Of Glucose

1. Rates of insulin release, glucose utilization (measured as [3H]water formation from [5-3H]glucose) and glucose oxidation (measured as14CO2 formation from [1-14C]- or [6-14C]-glucose) were determined in mouse pancreatic islets incubated in vitro, and were used to estimate the rate of oxidation of glucose by the pentose cycle pathway under various conditions. Rates of oxidation of [U-14C]ribose and [U-14C]xylitol were also measured. 2. Insulin secretion was stimulated fivefold when the medium glucose concentration was raised from 3.3 to 16.7mm in the absence of caffeine; in the presence of caffeine (5mm) a similar increase in glucose concentration evoked a much larger (30-fold) increase in insulin release. Glucose utilization was also increased severalfold as the intracellular glucose concentration was raised over this range, particularly between 5 and 11mm, but the rate of oxidation of glucose via the pentose cycle was not increased. 3. Glucosamine (20mm) inhibited glucose-stimulated insulin release and glucose utilization but not glucose metabolism via the pentose cycle. No evidence was obtained for any selective effect on the metabolism of glucose via the pentose cycle of tolbutamide, glibenclamide, dibutyryl 3′:5′-cyclic AMP, glucagon, caffeine, theophylline, ouabain, adrenaline, colchicine, mannoheptulose or iodoacetamide. Phenazine methosulphate (5μm) increased pentose-cycle flux but inhibited glucose-stimulated insulin release. 4. No formation of14CO2 from [U-14C]ribose could be detected: [U-14C]xylitol gave rise to small amounts of14CO2. Ribose and xylitol had no effect on the rate of oxidation of glucose; ribitol and xylitol had no effect on the rate of glucose utilization. Ribose, ribitol and xylitol did not stimulate insulin release under conditions in which glucose produced a large stimulation. 5. It is concluded that in normal mouse islets glucose metabolism via the pentose cycle does not play a primary role in insulin-secretory responses.

Lack of long-term β-cell glucotoxicity in vitro in pancreatic islets isolated from two mouse strains (C57BL/6J; C57BL/KsJ) with different sensitivities of the β-cells to hyperglycaemia in vivo

1993 ◽  
Vol 136 (2) ◽  
pp. 289-296 ◽  
Author(s):  
C. Svensson ◽  
S. Sandler ◽  
C. Hellerström
Keyword(s):  
Insulin Secretion ◽  
Glucose Metabolism ◽  
Pancreatic Islets ◽  
Insulin Release ◽  
Insulin Biosynthesis ◽  
Mouse Strains ◽  
Β Cells ◽  
Insulin Mrna

ABSTRACT Previous studies have shown that 4 weeks after syngeneic transplantation of a suboptimal number of islets into either C57BL/6J (BL/6J) or C57BL/KsJ (BL/KsJ) diabetic mice there is an impaired insulin secretion by the perfused grafts. After normalization of the blood glucose level with a second islet graft, the BL/6J strain showed restored insulin secretion whilst that of the BL/KsJ strain remained impaired. The aim of the present work was to study the effects of glucose on the in-vitro function of islet β-cells from these two mouse strains, with different sensitivities of their β-cells to glucose in vivo. Isolated pancreatic islets from each strain were kept for 1 week in tissue culture at 5·6, 11, 28 or 56 mmol glucose/l and were subsequently analysed with regard to insulin release, (pro)-insulin and total protein biosynthesis, insulin, DNA and insulin mRNA contents and glucose metabolism. Islets from both strains cultured at 28 or 56 mmol glucose/l showed an increased accumulation of insulin in the culture medium and an enhanced glucose-stimulated insulin release compared with corresponding control islets cultured at 11 mmol glucose/l. After culture at either 5·6 or 56 mmol/l, rates of (pro)insulin biosynthesis were decreased in BL/KsJ islets in short-term incubations at 17 mmol glucose/l, whereas islets cultured at 56 mmol glucose/l showed a marked increase at 1·7 mmol glucose/l. In BL/6J islets, the (pro)insulin biosynthesis rates were similar to those of the BL/KsJ islets with one exception, namely that no decrease was observed at 56 mmol glucose/l. Islets of both strains showed a decreased insulin content after culture with 56 mmol glucose/l. Insulin mRNA content was increased in islets cultured in 28 or 56 mmol glucose/l from both mouse strains. Glucose metabolism showed no differences in the rates of glucose oxidation, however, in islets cultured in 56 mmol glucose/l the utilization of glucose was increased in both BL/6J and BL/KsJ animals. There were no differences in DNA content in islets cultured at different glucose concentrations, suggesting no enhancement of cell death. The present study indicates that, irrespective of genetic background, murine β-cells can adapt to very high glucose concentrations in vitro without any obvious signs of so-called glucotoxicity. Previously observed signs of glucotoxicity in vivo in BL/KsJ islets appear not to be related only to glucose but rather to an additional factor in the diabetic environment. Journal of Endocrinology (1993) 136, 289–296

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