Protein Kinase C and Calcium Regulation of Adenylyl Cyclase in Isolated Rat Pancreatic Islets

Tian, Yingrao; Laychock, Suzanne G.

doi:10.2337/diabetes.50.11.2505

Cited by 41 publications

(36 citation statements)

References 73 publications

(70 reference statements)

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“…Although ACh is not usually recognized as a stimulator of cAMP production at low glucose concentrations by the normal islet (30 -32), a recent report suggests that such is the case (33). Using Wistar islets incubated at low glucose concentrations, we were unable to confirm this observation.…”

Section: Discussioncontrasting

confidence: 54%

Restitution of Defective Glucose-Stimulated Insulin Secretion in Diabetic GK Rat by Acetylcholine Uncovers Paradoxical Stimulatory Effect of β-Cell Muscarinic Receptor Activation on cAMP Production

et al. 2005

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Because acetylcholine (ACh) is a recognized potentiator of glucose-stimulated insulin release in the normal ␤-cell, we have studied ACh's effect on islets of the Goto-Kakizaki (GK) rat, a spontaneous model of type 2 diabetes. We first verified that ACh was able to restore the insulin secretory glucose competence of the GK ␤-cell. Then, we demonstrated that in GK islets 1) ACh elicited a first-phase insulin release at low glucose, whereas it had no effect in Wistar; 2) total phospholipase C activity, ACh-induced inositol phosphate production, and intracellular free calcium concentration (

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Section: Discussioncontrasting

confidence: 54%

Restitution of Defective Glucose-Stimulated Insulin Secretion in Diabetic GK Rat by Acetylcholine Uncovers Paradoxical Stimulatory Effect of β-Cell Muscarinic Receptor Activation on cAMP Production

et al. 2005

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“…Supportive of this notion was that the glucose-induced elevation of intracellular [cAMP] in ␤-cells could be completely blocked by verapamil, which inhibits the glucose-induced influx of extracellular Ca 2ϩ to raise ␤-cell cytosolic [Ca 2ϩ ] i (17,30,31). In this regard, it has been previously shown that increased /calmodulindependent adenylate cyclase (type 3) activity, thereby leading to an increase of cAMP level in pancreatic rat islets (32). Thus, according to these observations, we propose the following pathway where glucose-or glyburide-mediated Ca 2ϩ influx increases cytosolic Ca 2ϩ , which may activate the Ca 2ϩ /calmodulin-dependent AC type 3, leading to an increase of cAMP levels that activate PKA to then mediate Erk-1/2 phosphorylation.…”

Section: S6kmentioning

confidence: 58%

Differential Activation Mechanisms of Erk-1/2 and p70S6K by Glucose in Pancreatic β-Cells

et al. 2003

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“…Stimulation of this margination was lost after PKC downregulation, suggesting that PKC-α, βII or ε might be involved. In addition, cAMP concentrations in the beta cell are increased with PKC activation probably at the level of adenylyl cyclase phosphorylation and activation [158]. This suggests the existence of cross-talk between PKC signalling and the generation of cAMP, a well-known potentiator of GSIS [159].…”

Section: Modulation Of Secretory Granule Transport and Exocytosismentioning

confidence: 85%

Fatty acid metabolism and insulin secretion in pancreatic beta cells

2003

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Increases in glucose or fatty acids affect metabolism via changes in long-chain acyl-CoA formation and chronically elevated fatty acids increase total cellular CoA. Understanding the response of pancreatic beta cells to increased amounts of fuel and the role that altered insulin secretion plays in the development and maintenance of obesity and Type 2 diabetes is important. Data indicate that the activated form of fatty acids acts as an effector molecule in stimulus-secretion coupling. Glucose increases cytosolic long-chain acylCoA because it increases the "switch" compound malonyl-CoA that blocks mitochondrial β-oxidation, thus implementing a shift from fatty acid to glucose oxidation. We present arguments in support of the following: (i) A source of fatty acid either exogenous or endogenous (derived by lipolysis of triglyceride) is necessary to support normal insulin secretion; (ii) a rapid increase of fatty acids potentiates glucose-stimulated secretion by increasing fatty acyl-CoA or complex lipid concentrations that act distally by modulating key enzymes such as protein kinase C or the exocytotic machinery; (iii) a chronic increase of fatty acids enhances basal secretion by the same mechanism, but promotes obesity and a diminished response to stimulatory glucose; (iv) agents which raise cAMP act as incretins, at least in part, by stimulating lipolysis via beta-cell hormone-sensitive lipase activation. Furthermore, increased triglyceride stores can give higher rates of lipolysis and thus influence both basal and stimulated insulin secretion. These points highlight the important roles of NEFA, LC-CoA, and their esterified derivatives in affecting insulin secretion in both normal and pathological states. [Diabetologia (2003[Diabetologia ( ) 46:1297[Diabetologia ( -1312

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Protein Kinase C and Calcium Regulation of Adenylyl Cyclase in Isolated Rat Pancreatic Islets

Cited by 41 publications

References 73 publications

Restitution of Defective Glucose-Stimulated Insulin Secretion in Diabetic GK Rat by Acetylcholine Uncovers Paradoxical Stimulatory Effect of β-Cell Muscarinic Receptor Activation on cAMP Production

Restitution of Defective Glucose-Stimulated Insulin Secretion in Diabetic GK Rat by Acetylcholine Uncovers Paradoxical Stimulatory Effect of β-Cell Muscarinic Receptor Activation on cAMP Production

Differential Activation Mechanisms of Erk-1/2 and p70S6K by Glucose in Pancreatic β-Cells

Fatty acid metabolism and insulin secretion in pancreatic beta cells

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