scholarly journals The β-cell glibenclamide receptor is an ADP-binding protein

1990 ◽  
Vol 268 (3) ◽  
pp. 713-718 ◽  
Author(s):  
I Niki ◽  
J L Nicks ◽  
S J H Ashcroft
Keyword(s):  
Beta Cell ◽  
Insulin Release ◽  
Plasma Membranes ◽  
Pancreatic Beta Cell ◽  
Atp Depletion ◽  
K Channel ◽  
Whole Cells ◽  
Cell Plasma ◽  
Beta Cell Line ◽  
Extracellular Side

The effects of ADP on [3H]glibenclamide binding to membranes and whole cells, the activity of the ATP-sensitive K+ channel (K-ATP channel), intracellular Ca2+ concentration and insulin secretion were studied in a hamster pancreatic beta-cell line, HIT T15. ADP dose-dependently inhibited [3H]glibenclamide binding to membranes and to whole cells in a competitive manner. ADP-agarose also inhibited the binding to whole cells. The activity of the K-ATP channel was assayed by measuring 86Rb efflux from whole cells. ADP inhibited the 86Rb efflux elicited either by diazoxide or by ATP depletion. In the presence, but not in the absence, of extracellular Ca2+, ADP evoked a rapid and sustained increase in intracellular Ca2+ concentration as estimated with the fluorescent dye quin 2. Insulin release from HIT cells was also increased by 0.5-2 mM-ADP in the presence of 0.5 mM-glucose. These effects of ADP on glibenclamide binding, K-ATP channel activity and insulin release were specific for ADP, and were not reproduced by any other nucleotide so far tested. The present findings strongly suggest that ADP and sulphonylureas have common binding sites on the extracellular side of beta-cell plasma membranes, where they inhibit the activity of the K-ATP channel, resulting in an increase in intracellular Ca2+ concentration and insulin release.

ATP-sensitive K+ channel-independent glucose action in rat pancreatic beta-cell

1994 ◽  
Vol 266 (3) ◽  
pp. C622-C627 ◽  
Author(s):  
T. Aizawa ◽  
Y. Sato ◽  
F. Ishihara ◽  
N. Taguchi ◽  
M. Komatsu ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Beta Cell ◽  
Phospholipase C ◽  
Insulin Release ◽  
Islet Cells ◽  
Pancreatic Beta Cell ◽  
Cytosolic Calcium ◽  
Sweet Taste ◽  
K Channel ◽  
Glucose Molecule

The nature of ATP-sensitive K+ (K+ATP) channel-independent, insulinotropic action of glucose was investigated using non-glucose-primed pancreatic islets. When the beta-cell was depolarized with K+, glucose dose dependently stimulated insulin release despite inhibition of the K+ATP channel closure by diazoxide. K+ depolarization could be replaced with BAY K 8644, a calcium channel agonist. Prior fasting of rats and lowering ambient temperature greatly suppressed glucose oxidation and utilization by the islet cells and abolished insulin release in response to high glucose alone. However, under these conditions, the K+ATP channel-independent, glucose-induced insulin release was clearly demonstrable. p-Nitrophenyl-alpha-D-glucopyranoside (sweet taste inhibitor) but not its beta-isomer, neomycin (phospholipase C inhibitor) and staurosporine (C kinase blocker) inhibited the K+ATP channel-independent, insulinotropic action of glucose. For the K+ATP channel-independent glucose-induced insulin release 1) elevation of cytosolic calcium is required, 2) minute glucose metabolism is enough, if glucose metabolism is necessary, and 3) direct recognition of glucose molecule, phospholipase C, and protein kinase C appear to be involved.

scholarly journals Characterization of the solubilized glibenclamide receptor in a hamster pancreatic β-cell line, HIT T15

1991 ◽  
Vol 277 (3) ◽  
pp. 619-624 ◽  
Author(s):  
I Niki ◽  
M Welsh ◽  
P O Berggren ◽  
P Hubbard ◽  
S J H Ashcroft
Keyword(s):  
Beta Cell ◽  
Cell Line ◽  
Beta Cells ◽  
Specific Binding ◽  
Pancreatic Beta Cell ◽  
Active Form ◽  
K Channel ◽  
Scatchard Analysis ◽  
Beta Cell Line ◽  
20 Nm

The glibenclamide receptor, a putative ATP-sensitive K+ channel in the hamster pancreatic beta-cell line HIT T15, was solubilized by using the zwitterionic detergent CHAPS. [3H]Glibenclamide binding was dependent on the incubation time and on the concentration of soluble membrane protein. Over 80% of [3H]glibenclamide bound could be displaced with 1 microM non-labelled glibenclamide. The curve relating specific binding to the concentration of [3H]glibenclamide (1-20 nM) showed saturation kinetics. Scatchard analysis suggested a single class of non-interacting binding sites with a Kd of 3.3 nM and a Bmax. of 90 fmol/mg of protein. [3H]Glibenclamide binding to solubilized membranes was inhibited by glibenclamide, tolbutamide and meglitinide. The relative potency of these agents on binding of [3H]glibenclamide to solubilized membranes was similar to that observed with microsomal preparations and paralleled their effects on K-ATP channel activity, measured as 86Rb efflux. These data show that the sulphonylurea receptor in the pancreatic beta-cell can be solubilized in an active form retaining specificity for sulphonylureas. ADP, which inhibits [3H]glibenclamide binding to microsomal preparations or intact HIT beta-cells, did not inhibit binding to the solubilized receptor. Incubation of intact HIT beta-cells with 125I-glibenclamide derivative followed by exposure to u.v. light resulted in covalent labelling of a peptide of 65 kDa on SDS/PAGE. The extent of labelling increased with 125I-glibenclamide derivative concentration (1-20 nM) and was inhibited in the presence of excess unlabelled glibenclamide.

Electrical activity, cAMP concentration, and insulin release in mouse islets of Langerhans

1985 ◽  
Vol 248 (1) ◽  
pp. C145-C153 ◽  
Author(s):  
G. T. Eddlestone ◽  
S. B. Oldham ◽  
L. G. Lipson ◽  
F. H. Premdas ◽  
P. M. Beigelman
Keyword(s):  
Beta Cell ◽  
Electrical Activity ◽  
Insulin Release ◽  
Electrical Response ◽  
Pancreatic Beta Cell ◽  
Fold Increase ◽  
Camp Concentration ◽  
Camp Content ◽  
Cell Plasma ◽  
Dependent Protein

The influence of forskolin and 3-iso-butyl-1-methylxanthine (IBMX) on mouse pancreatic beta-cell electrical activity, whole islet cAMP content, and insulin release were investigated. The two drugs potentiated to a similar extent both glucose-stimulated electrical activity and insulin release. In terms of the electrical response, both drugs potentiated the silent depolarization of the membrane in response to low (substimulatory) glucose concentrations, whereas at higher (stimulatory) glucose concentrations they caused an increase in the plateau fraction, with a response similar to the effect of increasing the glucose concentration. Both phases of insulin release were increased by each of the drugs. Ten micromolar forskolin and 100 microM IBMX caused an increase in intraislet adenosine 3',5'-cyclic monophosphate (cAMP) in the presence of 11.1 mM glucose, the former a 17-fold and the latter a 2-fold increase over the cAMP concentration in the presence of glucose alone. Because the two drugs lead to an increase in islet cAMP content, it is proposed that protein phosphorylation resulting from an activation of beta-cell cAMP-dependent protein kinases is responsible for the potentiation of the glucose-induced insulin release and beta-cell electrical activity. The observed effects on electrical activity are compatible with the hypothesis that cAMP-dependent phosphorylation induces alteration of the kinetics of the calcium-sensitive potassium permeability of the beta-cell plasma membrane. The increase in calcium entry into the beta-cell that would result from these alterations may be responsible for the cAMP-dependent potentiation of insulin release.

The betaHC-9 pancreatic beta-cell line preserves the characteristics of progenitor mouse islets

Diabetes ◽  
1996 ◽  
Vol 45 (12) ◽  
pp. 1766-1773 ◽  
Author(s):  
M. Noda ◽  
M. Komatsu ◽  
G. W. Sharp
Keyword(s):  
Beta Cell ◽  
Cell Line ◽  
Pancreatic Beta Cell ◽  
Beta Cell Line ◽  
Mouse Islets

scholarly journals Regulated expression and function of the GABAB receptor in human pancreatic beta cell line and islets

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Latif Rachdi ◽  
Alicia Maugein ◽  
Severine Pechberty ◽  
Mathieu Armanet ◽  
Juliette Hamroune ◽  
...  
Keyword(s):  
Beta Cell ◽  
Cell Line ◽  
Gabab Receptor ◽  
Pancreatic Beta Cell ◽  
Beta Cell Line ◽  
Regulated Expression ◽  
And Function

scholarly journals Polarization of chlorotetracycline fluorescence in pancreatic islet cells and its response to calcium ions and D-glucose

1979 ◽  
Vol 178 (1) ◽  
pp. 187-193 ◽  
Author(s):  
I B Täljedal
Keyword(s):  
Beta Cell ◽  
Fluorescence Intensity ◽  
Calcium Ions ◽  
Pancreatic Beta Cells ◽  
Plasma Membranes ◽  
Islet Cells ◽  
Pancreatic Islet Cells ◽  
Cell Plasma ◽  
Polarization Of Fluorescence ◽  
Parametric Testing

Suspensions rich in pancreatic beta-cells were prepared from non-inbred ob/ob-mice, incubated with 10 micrometer-chlorotetracycline, and analysed for fluorescence polarization in a microscope. Throughout the temperature range 16–38 degrees C, fluorescence was enhanced by 5 mM-Ca2+ in the incubation medium; 20 mM-D-glucose decreased the fluorescence measured in the presence of Ca2+. Fluorescence showed a curvilinear negative regression on temperature. The curves were rectified to a virtually ideal degree by Arrhenius transformations of data. Non-parametric testing of differences between linearized regression lines forms the basis for the following conclusions. The temperature-dependence of fluorescence intensity appeared to be smaller for Ca2+-specific signals than for the background fluorescence of chlorotetracycline in Ca2+-deficient cells. D-Glucose significantly diminished the polarization of fluorescence in cells incubated with Ca2+. It is suggested that D-glucose increases the mobility of Ca2+ in beta-cell plasma membranes; this mobility increase may help to explain previously reported effects of D-glucose on 45Ca2+ fluxes and membrane electric potential.

Functional analysis of a conditionally transformed pancreatic beta-cell line

Diabetes ◽  
1998 ◽  
Vol 47 (9) ◽  
pp. 1419-1425 ◽  
Author(s):  
N. Fleischer ◽  
C. Chen ◽  
M. Surana ◽  
M. Leiser ◽  
L. Rossetti ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Beta Cell ◽  
Cell Line ◽  
Pancreatic Beta Cell ◽  
Beta Cell Line

scholarly journals High dose of histone deacetylase inhibitors affects insulin secretory mechanism of pancreatic beta cell line

2018 ◽  
Vol 52 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Eiji Yamato
Keyword(s):  
Insulin Secretion ◽  
Beta Cell ◽  
Cell Line ◽  
Beta Cells ◽  
Pancreatic Beta Cells ◽  
Pancreatic Beta Cell ◽  
High Dose ◽  
Min6 Cells ◽  
Beta Cell Line ◽  
High Doses

Abstract Objective. Histone deacytylase inhibitors (HDACis) inhibit the deacetylation of the lysine residue of proteins, including histones, and regulate the transcription of a variety of genes. Recently, HDACis have been used clinically as anti-cancer drugs and possible anti-diabetic drugs. Even though HDACis have been proven to protect the cytokine-induced damage of pancreatic beta cells, evidence also shows that high doses of HDACis are cytotoxic. In the present study, we, therefore, investigated the eff ect of HDACis on insulin secretion in a pancreatic beta cell line. Methods. Pancreatic beta cells MIN6 were treated with selected HDACis (trichostatin A, TSA; valproic acid, VPA; and sodium butyrate, NaB) in medium supplemented with 25 mM glucose and 13% heat-inactivated fetal bovine serum (FBS) for indicated time intervals. Protein expression of Pdx1 and Mafa in MIN6 cells was demonstrated by immunohistochemistry and immunocytochemistry, expression of Pdx1 and Mafa genes was measured by quantitative RT-PCR method. Insulin release from MIN6 cells and insulin cell content were estimated by ELISA kit. Superoxide production in MIN6 cells was measured using a Total ROS/Superoxide Detection System. Results. TSA, VPA, and NaB inhibited the expression of Pdx1 and Mafa genes and their products. TSA treatment led to beta cell malfunction, characterized by enhanced insulin secretion at 3 and 9 mM glucose, but impaired insulin secretion at 15 and 25 mM glucose. Th us, TSA induced dysregulation of the insulin secretion mechanism. TSA also enhanced reactive oxygen species production in pancreatic beta cells. Conclusions. Our results showed that HDACis caused failure to suppress insulin secretion at low glucose concentrations and enhance insulin secretion at high glucose concentrations. In other words, when these HDACis are used clinically, high doses of HDACis may cause hypoglycemia in the fasting state and hyperglycemia in the fed state. When using HDACis, physicians should, therefore, be aware of the capacity of these drugs to modulate the insulin secretory capacity of pancreatic beta cells.

scholarly journals Identification of genes regulated by glucose in a pancreatic beta-cell line by a new method for subtraction of mRNA

Diabetologia ◽  
1996 ◽  
Vol 39 (11) ◽  
pp. 1293-1298 ◽  
Author(s):  
E. Yamato ◽  
H. Ikegami ◽  
J.-I. Miyazaki ◽  
T. Ogihara
Keyword(s):  
Beta Cell ◽  
Cell Line ◽  
Pancreatic Beta Cell ◽  
New Method ◽  
Beta Cell Line
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