Hormonal and non-hormonal protein biosynthesis in the pancreatic beta cell of the intact rat after prolonged hyperglycaemia

1984 ◽  
Vol 107 (3) ◽  
pp. 382-389 ◽  
Author(s):  
J. Logothetopoulos ◽  
Nancy Valiquette
Keyword(s):  
Beta Cell ◽  
Pancreatic Islets ◽  
Protein Biosynthesis ◽  
Pancreatic Beta Cell ◽  
Enzymatic Digestion ◽  
Insulin Biosynthesis ◽  
Isolated Pancreatic Islets ◽  
Pancreatic Cells

Abstract. We examined the relative changes in the rates of biosynthesis of (pro)insulin and of non-hormonal beta cell proteins in rats with pronounced hyperglycaemia for up to several days. Labelling of pancreatic cells in vivo eliminated certain pitfalls that we encountered when isolated pancreatic islets from these rats were labelled in vitro. Rats were infused with glucose or buffer solutions for 24 and 72 h. Glucose-infused rats had sustained hyperglycaemia throughout the infusion periods. l[4,5-3H]leucine or l[2,3-3H]tryptophan (an amino acid absent from proinsulin) was injected iv 30 min before the rats were killed. Pancreatic islets were isolated by enzymatic digestion of the pancreas. Pancreatic islets from the rats injected with [3H]leucine were processed for measurement of [3H]proinsulin and [3H]insulin by a double antibody immunoprecipitation procedure. Islets from rats injected with [3H]tryptophan were processed for autoradiography, in order to assess the incorporation of label into non-hormonal sedentary beta cell proteins. Incorporation of [3H]leucine into proinsulin and insulin per beta cell was estimated to be about 2–2.5 (24 h infusion) and 3.5–4 (72 h infusion) times greater in the hyperglycaemic than in normoglycaemic rats. Incorporation of [3H]tryptophan into non-hormonal beta cell proteins showed similar increments in the hyperglycaemic rats. Contrary to our expectation these results indicate that glucose does not exert a significant preferential effect on insulin biosynthesis even after sustained stimulation of the beta cells. Instead, glucose seems to increase equally the incorporation of labelled amino acids into proinsulin and into non-hormonal, beta cell proteins.

Comparative toxicity of alloxan, N-alkylalloxans and ninhydrin to isolated pancreatic islets in vitro

1997 ◽  
Vol 155 (2) ◽  
pp. 283-293 ◽  
Author(s):  
A Jorns ◽  
R Munday ◽  
M Tiedge ◽  
S Lenzen
Keyword(s):  
Beta Cell ◽  
Pancreatic Islets ◽  
Beta Cells ◽  
Pancreatic Beta Cells ◽  
Ultrastructural Changes ◽  
Cell Necrosis ◽  
High Concentrations ◽  
Beta Cell Necrosis

The in vitro toxicity of the diabetogenic agent alloxan as documented by the induction of beta cell necrosis was studied in isolated ob/ob mouse pancreatic islets. The effect of alloxan has been compared with that of a number of N-alkyl alloxan derivatives and with that of the structurally related compound, ninhydrin. Alloxan and its derivatives were selectively toxic to pancreatic beta cells, with other endocrine cells and exocrine parenchymal cells being well preserved, even at high concentration. In contrast, ninhydrin was selectively toxic to pancreatic beta cells only at comparatively low concentration, destroying all islet cell types at high concentrations. The ultrastructural changes induced by all the test compounds in pancreatic beta cells in vitro were very similar to those observed during the development of alloxan diabetes in vivo. The relative toxicity of the various compounds to pancreatic beta cells in vitro was not, however, related to their ability to cause diabetes in vivo. Indeed, the non-diabetogenic substances ninhydrin, N-butylalloxan and N-isobutylalloxan were very much more toxic to isolated islets than the diabetogenic compounds alloxan and N-methylalloxan. These results suggest that the differences in diabetogenicity among alloxan derivatives are not due to intrinsic differences in the susceptibility of the pancreatic beta cells to their toxicity, but may reflect differences in distribution or metabolism. High concentrations of glucose protected islets against the harmful effects of alloxan and its derivatives, but not those of ninhydrin. Low levels of glucose, and non-carbohydrate nutrients, afforded little protection, indicating that the effect of glucose is not due to the production of reducing equivalents within the cell, 3-O-Methylglucose, which protects against alloan diabetes in vivo, did not protect against alloxan toxicity in vitro. Since 3-O-methylglucose is known to prevent uptake of alloxan by pancreatic beta cells, it appears that uptake of alloxan by the cell is not a prerequisite for the induction of beta cell necrosis.

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

scholarly journals In vivo and in vitro increased pancreatic beta-cell sensitivity to glucose in normal rats submitted to a 48-h hyperglycaemic period

Diabetologia ◽  
1993 ◽  
Vol 36 (7) ◽  
pp. 589-595 ◽  
Author(s):  
C. Thibault ◽  
C. Guettet ◽  
M. C. Laury ◽  
J. M. N'Guyen ◽  
M. A. Tormo ◽  
...  
Keyword(s):  
Beta Cell ◽  
Pancreatic Beta Cell ◽  
Cell Sensitivity

Culture Systems of Isolated Pancreatic Islets with Extracellular Matrix Biomimetics as Tissue-Engineered Constructs of the Pancreas

2021 ◽  
Author(s):  
Victor I Sevastianov ◽  
Natalia V Baranova ◽  
Lyudmila A Kirsanova ◽  
Anna S Ponomareva ◽  
Eugene A Nemets ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Pancreatic Islets ◽  
Human Pancreas ◽  
Isolated Pancreatic Islets ◽  
Tissue Specific ◽  
Culture Systems ◽  
Engineered Structures ◽  
The Creation

Abstract The creation of a tissue-engineered structure of the pancreas based on isolated pancreatic islets is hindered by problems associated with maintaining their viability and insulin-producing function. Both biopolymer and tissue-specific scaffolds can contribute to the preservation of the structure and function of pancreatic islets in vitro and in vivo. Comparative morphofunctional analysis in vitro of two different types of tissue-engineered structures of the pancreas, which represent culture systems of isolated islets with biomimetics of an extracellular matrix - a biopolymer collagen-containing scaffold and a tissue-specific scaffold obtained as a result of pancreatic decellularization, - was performed. The results showed that the use of scaffolds in the creation of a tissue-engineered design of the pancreas contributes not only to the preservation of the viability of the islets, but also to the prolongation of their insulin-producing functions, compared to the monoculture of the islets in vitro. A significant increase was found in the basal and stimulated (under glucose load) insulin concentrations in the tissue of engineered structures studied, at the same time the advantage of using a tissue-specific scaffold compared to a biopolymer collagen-containing scaffold was shown. We think that these studies will become a platform for creating a tissue-engineered design of the human pancreas for treatment of type 1 diabetes mellitus.

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 Gut-derived bacterial flagellin induces beta-cell inflammation and dysfunction

2021 ◽  
Author(s):  
Torsten P.M. Scheithauer ◽  
Hilde Herrema ◽  
Hongbing Yu ◽  
Guido J. Bakker ◽  
Maaike Winkelmeijer ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Beta Cell ◽  
Pancreatic Islets ◽  
Pancreatic Beta Cells ◽  
Cell Dysfunction ◽  
Insulin Gene Expression

AbstractObjectiveHyperglycemia and type 2 diabetes (T2D) are caused by failure of pancreatic beta cells. The role of the gut microbiota in T2D has been studied but causal links remain enigmatic.DesignObese individuals with or without T2D were included from two independent Dutch cohorts. Human data was translated in vitro and in vivo by using pancreatic islets from C57BL6/J mice and by injecting flagellin into obese mice.ResultsFlagellin is part of the bacterial locomotor appendage flagellum, present on gut bacteria including Enterobacteriaceae, which we show to be more abundant in the gut of individuals with T2D. Subsequently, flagellin induces a pro-inflammatory response in pancreatic islets mediated by the Toll-like receptor (TLR)-5 expressed on resident islet macrophages. This inflammatory response associated with beta-cell dysfunction, characterized by reduced insulin gene expression, impaired proinsulin processing and stress-induced insulin hypersecretion in vitro and in vivo in mice.ConclusionWe postulate that increased systemically disseminated flagellin in T2D is a contributing factor to beta cell failure in time and represents a novel therapeutic target.Graphical abstract

scholarly journals Morphological analysis of isolated rat pancreatic islets cultured under standard culture technique and with biopolymer microstructured collagen‑containing hydrogel

2017 ◽  
Vol 19 (2) ◽  
pp. 90-97
Author(s):  
L. A. Kirsanova ◽  
N. V. Baranova ◽  
G. N. Bubentsova ◽  
V. I. Sevastianov
Keyword(s):  
Pancreatic Islets ◽  
Structural Integrity ◽  
Culture Technique ◽  
Isolated Pancreatic Islets ◽  
Rat Islets ◽  
Standard Culture ◽  
Islet Survival ◽  
Isolated Rat

Introduction. Extracellular matrix play an essential role in providing structural integrity and physiological support to Langerhans islets in pancreas. Imitation of the native microenvironment can be useful for viability of isolated pancreatic islets in vitro and in vivo. Aim. The purpose of this study was to characterize and compare the effect of biopolymer microstructured collagen-containing hydrogel (BMCH) on isolated rat islets survival. Materials and methods. Islets were isolated by classic collagenase techniques with some modifications. There were used hystological, immunofluorescence and immunohystochemistry methods. Results. Rat islets cultured with collagen-based gel don’t revealed destructive changes of structure and remained viabile 7 days incubation. Conclusion. Positive effect of BMCH to rat islet survival was revealed.

scholarly journals Morphofunctional characteristic of endocrine part of pancreas under affecting of γ-HCH

2020 ◽  
Vol 80 (4) ◽  
pp. 152-160
Author(s):  
G. Tusupbekova ◽  
◽  
G. Meiramov ◽  
Keyword(s):  
Blood Serum ◽  
Pancreatic Islets ◽  
Organic Pollutant ◽  
Immunoreactive Insulin ◽  
Specific Method ◽  
Β Cells ◽  
Isolated Pancreatic Islets ◽  
Experimental Animals

In the last decades of the twentieth century, in the national economy of many countries, organochlorine pesticides were most widely used, characterized by stability in the external environment, the ability to cumulate in various tissues of organisms. Lindane (the gamma isomer of hexachlorocyclohexane) is listed as a restricted persistent organic pollutant and is an ecotoxic substance with severe and chronic effects on the human body. The study of the effect of lindane on carbohydrate metabolism at the present stage is still insufficient. This fact led to the study of the effect of γ-HCH on the insulinogenic function of the pancreas in in vivo and in vitro experiments. In experiments in vivo, the animals of the experimental groups were once orally administered γ-HCH at a dose equal to 1/5 DL50. Isolated pancreatic islets, precipitated in vitro and fixed on mica plates, were exposed to γ-HCH in amounts equivalent to 1/5 to 1/4 DL50. Paraffin sections of pancreatic tissue from experimental and control animals were stained with aldehyde fuchsin according to Gomori, and tissue preparations were also examined by a highly specific method for detecting insulin in β-cells using diethylpseudoisocyanin staining, followed by examination of the preparations in the ultraviolet light of a luminescent microscope. The samemethods were used to study preparations of isolated pancreatic islet tissue on the 4th day of cultivation. The influence of orally administered γ-HCH on the level of immunoreactive insulin in the blood of experimental animals was also studied. The insulin level was determined by the enzymatic-immunological method. The concentration of IRI was established before the start of the experiment and 4-4.5 hours after acute inoculation. Results and their significance. In the study of stained preparations of the pancreas of experimental animals, numerous islets of ordinary sizes were revealed, the cytoplasm of which was filled with aldehyde-fuccin granularity in quantities indistinguishable from those observed by microscopy of preparations of control animals. The value of the fluorescence coefficient in the histofluorimetric study of the control and experimental preparations did not differ significantly. However, the content of IRI in the blood serum showed a distinct decrease in the first hours after priming. In experiments in vitro, when studying the effect of γ-HCH on cultured tissue, introduced into the nutrient medium on the second day, in the field of view of the microscope, single, small pancreatic islets were revealed. Their number on a constant area of the plates was significantly lower than the value of the same indicator in the study of control preparations. Thus it has been shown that γ-HCH does not affect the histostructure of the endocrine pancreas, but causes a significant decrease in IRI in the blood serum, as well as a change in the histochemical characteristics of cultured β-cells.

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