scholarly journals Imidazoline antagonists of α2-adrenoceptors increase insulin release in vitro by inhibiting ATP-sensitive K+ channels in pancreatic β-cells

1992 ◽  
Vol 107 (1) ◽  
pp. 8-14 ◽  
Author(s):  
J.C. Jonas ◽  
T.D. Plant ◽  
J.C. Henquin
Keyword(s):  
Insulin Release ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
K Channels ◽  
Α2 Adrenoceptors ◽  
Release In Vitro

scholarly journals CK2 acts as a potent negative regulator of receptor-mediated insulin release in vitro and in vivo

2015 ◽  
Vol 112 (49) ◽  
pp. E6818-E6824 ◽  
Author(s):  
Mario Rossi ◽  
Inigo Ruiz de Azua ◽  
Luiz F. Barella ◽  
Wataru Sakamoto ◽  
Lu Zhu ◽  
...  
Keyword(s):  
Insulin Release ◽  
Cell Activity ◽  
Negative Regulator ◽  
Whole Body ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Release In Vitro

G protein-coupled receptors (GPCRs) regulate virtually all physiological functions including the release of insulin from pancreatic β-cells. β-Cell M3 muscarinic receptors (M3Rs) are known to play an essential role in facilitating insulin release and maintaining proper whole-body glucose homeostasis. As is the case with other GPCRs, M3R activity is regulated by phosphorylation by various kinases, including GPCR kinases and casein kinase 2 (CK2). At present, it remains unknown which of these various kinases are physiologically relevant for the regulation of β-cell activity. In the present study, we demonstrate that inhibition of CK2 in pancreatic β-cells, knockdown of CK2α expression, or genetic deletion of CK2α in β-cells of mutant mice selectively augmented M3R-stimulated insulin release in vitro and in vivo. In vitro studies showed that this effect was associated with an M3R-mediated increase in intracellular calcium levels. Treatment of mouse pancreatic islets with CX4945, a highly selective CK2 inhibitor, greatly reduced agonist-induced phosphorylation of β-cell M3Rs, indicative of CK2-mediated M3R phosphorylation. We also showed that inhibition of CK2 greatly enhanced M3R-stimulated insulin secretion in human islets. Finally, CX4945 treatment protected mice against diet-induced hyperglycemia and glucose intolerance in an M3R-dependent fashion. Our data demonstrate, for the first time to our knowledge, the physiological relevance of CK2 phosphorylation of a GPCR and suggest the novel concept that kinases acting on β-cell GPCRs may represent novel therapeutic targets.

scholarly journals RGS4 is a negative regulator of insulin release from pancreatic β-cells in vitro and in vivo

2010 ◽  
Vol 107 (17) ◽  
pp. 7999-8004 ◽  
Author(s):  
Inigo Ruiz de Azua ◽  
Marco Scarselli ◽  
Erica Rosemond ◽  
Dinesh Gautam ◽  
William Jou ◽  
...  
Keyword(s):  
Insulin Release ◽  
Negative Regulator ◽  
Β Cells ◽  
Pancreatic Β Cells

scholarly journals Regulation of voltage-gated K+channels by glucose metabolism in pancreatic β-cells

FEBS Letters ◽  
2009 ◽  
Vol 583 (13) ◽  
pp. 2225-2230 ◽  
Author(s):  
Masashi Yoshida ◽  
Katsuya Dezaki ◽  
Shiho Yamato ◽  
Atsushi Aoki ◽  
Hitoshi Sugawara ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
K Channels ◽  
Voltage Gated

scholarly journals Long-Term Exposure of Pancreatic β-Cells to Palmitate Results in SREBP-1C-Dependent Decreases in GLP-1 Receptor Signaling via CREB and AKT and Insulin Secretory Response

Endocrinology ◽  
2016 ◽  
Vol 157 (6) ◽  
pp. 2243-2258 ◽  
Author(s):  
Annalisa Natalicchio ◽  
Giuseppina Biondi ◽  
Nicola Marrano ◽  
Rossella Labarbuta ◽  
Federica Tortosa ◽  
...  
Keyword(s):  
Protein Expression ◽  
Insulin Release ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Camp Response Element ◽  
Element Binding Protein ◽  
Viral Oncogene Homolog ◽  
Erk Kinase

The effects of prolonged exposure of pancreatic β-cells to high saturated fatty acids on glucagon-like peptide-1 (GLP-1) action were investigated. Murine islets, human pancreatic 1.1B4 cells, and rat INS-1E cells were exposed to palmitate for 24 hours. mRNA and protein expression/phosphorylation were measured by real-time RT-PCR and immunoblotting, respectively. Specific short interfering RNAs were used to knockdown expression of the GLP-1 receptor (Glp1r) and Srebf1. Insulin release was assessed with a specific ELISA. Exposure of murine islets, as well as of human and INS-1E β-cells, to palmitate reduced the ability of exendin-4 to augment insulin mRNA levels, protein content, and release. In addition, palmitate blocked exendin-4-stimulated cAMP-response element-binding protein and v-akt murine thymoma viral oncogene homolog phosphorylation, whereas phosphorylation of MAPK-ERK kinase-1/2 and ERK-1/2 was not altered. Similarly, RNA interference-mediated suppression of Glp1r expression prevented exendin-4-induced cAMP-response element-binding protein and v-akt murine thymoma viral oncogene homolog phosphorylation, but did not impair exendin-4 stimulation of MAPK-ERK kinase-1/2 and ERK-1/2. Both islets from mice fed a high fat diet and human and INS-1E β-cells exposed to palmitate showed reduced GLP-1 receptor and pancreatic duodenal homeobox-1 (PDX-1) and increased sterol regulatory element-binding protein (SREBP-1C) mRNA and protein levels. Furthermore, suppression of SREBP-1C protein expression prevented the reduction of PDX-1 and GLP-1 receptor levels and restored exendin-4 signaling and action. Finally, treatment of INS-1E cells with metformin for 24 h resulted in inhibition of SREBP-1C expression, increased PDX-1 and GLP-1 receptor levels, consequently, enhancement of exendin-4-induced insulin release. Palmitate impairs exendin-4 effects on β-cells by reducing PDX-1 and GLP-1 receptor expression and signaling in a SREBP-1C-dependent manner. Metformin counteracts the impairment of GLP-1 receptor signaling induced by palmitate.

Monolayer Culture of Human Fetal and Adult Pancreas. Static and Dynamic Studies of Insulin Release In Vitro

1980 ◽  
Vol 12 (08) ◽  
pp. 354-360 ◽  
Author(s):  
S. Kawazu ◽  
Y. Kanazawa ◽  
M. Hayashi ◽  
M. Ikeuchi ◽  
T. Nakai ◽  
...  
Keyword(s):  
Insulin Release ◽  
Monolayer Culture ◽  
Dynamic Studies ◽  
Release In Vitro

scholarly journals Teucrium polium: Potential Drug Source for Type 2 Diabetes Mellitus

Biology ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 128
Author(s):  
Yaser Albadr ◽  
Andrew Crowe ◽  
Rima Caccetta
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Insulin Secretion ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Glucose Levels ◽  
Teucrium Polium

The prevalence of type 2 diabetes mellitus is rising globally and this disease is proposed to be the next pandemic after COVID-19. Although the cause of type 2 diabetes mellitus is unknown, it is believed to involve a complex array of genetic defects that affect metabolic pathways which eventually lead to hyperglycaemia. This hyperglycaemia arises from an inability of the insulin-sensitive cells to sufficiently respond to the secreted insulin, which eventually results in the inadequate secretion of insulin from pancreatic β-cells. Several treatments, utilising a variety of mechanisms, are available for type 2 diabetes mellitus. However, more medications are needed to assist with the optimal management of the different stages of the disease in patients of varying ages with the diverse combinations of other medications co-administered. Throughout modern history, some lead constituents from ancient medicinal plants have been investigated extensively and helped in developing synthetic antidiabetic drugs, such as metformin. Teucrium polium L. (Tp) is a herb that has a folk reputation for its antidiabetic potential. Previous studies indicate that Tp extracts significantly decrease blood glucose levels r and induce insulin secretion from pancreatic β-cells in vitro. Nonetheless, the constituent/s responsible for this action have not yet been elucidated. The effects appear to be, at least in part, attributable to the presence of selected flavonoids (apigenin, quercetin, and rutin). This review aims to examine the reported glucose-lowering effect of the herb, with a keen focus on insulin secretion, specifically related to type 2 diabetes mellitus. An analysis of the contribution of the key constituent flavonoids of Tp extracts will also be discussed.

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