Block of non-L-, non-N-type Ca2+ channels in rat insulinoma RINm5F cells by ?-agatoxin IVA and ?-conotoxin MVIIC

1995 ◽  
Vol 429 (6) ◽  
pp. 762-771 ◽  
Author(s):  
V. Magnelli ◽  
A. Pollo ◽  
E. Sher ◽  
E. Carbone
Keyword(s):  
Rinm5f Cells ◽  
Rat Insulinoma ◽  
Ca2 Channels

Down-regulation of voltage-gated Ca2+ channels in Ca2+ store-depleted rat insulinoma RINm5F cells

BioMedicine ◽  
2013 ◽  
Vol 3 (3) ◽  
pp. 130-139 ◽  
Author(s):  
Yuk M. Leung ◽  
Kar L. Wong ◽  
Shiao W. Chen ◽  
Dah Y. Lu ◽  
Chang S. Kuo ◽  
...  
Keyword(s):  
Rinm5f Cells ◽  
Down Regulation ◽  
Voltage Gated ◽  
Rat Insulinoma ◽  
Ca2 Channels

Down-regulation of non-L-, non-N-type (Q-like) Ca2+ channels by Lambert-Eaton myasthenic syndrome (LEMS) antibodies in rat insulinoma RINm5F cells

FEBS Letters ◽  
1996 ◽  
Vol 387 (1) ◽  
pp. 47-52 ◽  
Author(s):  
V. Magnelli ◽  
C. Grassi ◽  
E. Parlatore ◽  
E. Sher ◽  
E. Carbone
Keyword(s):  
Rinm5f Cells ◽  
Down Regulation ◽  
Myasthenic Syndrome ◽  
Rat Insulinoma ◽  
Ca2 Channels

Up-regulation of L- and non-L, non-N-type Ca2+ channels by basal and stimulated protein kinase C activation in insulin-secreting RINm5F cells

FEBS Letters ◽  
1996 ◽  
Vol 391 (1-2) ◽  
pp. 189-194 ◽  
Author(s):  
D. Platano ◽  
A. Pollo ◽  
E. Carbone ◽  
G. Aicardi
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Rinm5f Cells ◽  
Kinase C ◽  
Protein Kinase C Activation ◽  
Ca2 Channels

scholarly journals Inhibition of adenylate cyclase activity by galanin in rat insulinoma cells is mediated by the G-protein Gi3

1994 ◽  
Vol 303 (2) ◽  
pp. 369-375 ◽  
Author(s):  
P de Mazancourt ◽  
P K Goldsmith ◽  
L S Weinstein
Keyword(s):  
Adenylate Cyclase ◽  
G Protein ◽  
Pancreatic Beta Cells ◽  
Protein S ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Rinm5f Cells ◽  
Insulinoma Cells ◽  
Galanin Receptors ◽  
Rat Insulinoma

Galanin inhibits adenylate cyclase activity and insulin secretion and modulates ion channels in pancreatic beta-cells through pertussis-toxin-sensitive G-protein(s). Antibodies directed against the C-terminal region of specific G-protein alpha-subunits were used to determine which G-protein(s) couple galanin receptors to inhibition of adenylate cyclase in the rat insulinoma cell line RINm5F. Preincubation of membranes with EC antibody (anti-alpha i3) decreased the inhibition of forskolin-stimulated adenylate cyclase activity by galanin (100 nM) by 45% compared with control IgG (P < 0.05) whereas preincubation with AS (anti-alpha i1, alpha i2) or GO (anti-alpha o) antibodies had no significant effect. To confirm these results, RINm5F cells were exposed intermittently over a 4-day period to phosphorothioate oligodeoxynucleotides that were either sense or antisense to alpha i1, alpha i2, alpha i3 or alpha o. Oligodeoxynucleotides antisense to alpha i2, alpha i3 and alpha o specifically decreased the levels of the targeted alpha-subunit in membranes. alpha i1 was undetectable in these cells. Inhibition of adenylate cyclase activity by galanin was largely abolished in membranes from cells exposed to the oligodeoxynucleotide antisense to alpha i3, whereas all other oligodeoxynucleotides had no significant effect on this pathway. Indirect immunofluorescence and immunoblotting of specific membrane fractions with EC antibody show significant localization of alpha i3 to intracellular membrane compartments. These results suggest that Gi3 is the G protein that couples galanin receptors to inhibition of adenylate cyclase activity in RINm5F cells.

Dexamethasone pretreatment of rat insulinoma cells decreases binding of glucagon-like peptide-1(7–36)amide

1990 ◽  
Vol 126 (3) ◽  
pp. 445-450 ◽  
Author(s):  
G. Richter ◽  
R. Göke ◽  
B. Göke ◽  
R. Arnold
Keyword(s):  
Biological Action ◽  
Inhibitory Effects ◽  
Rinm5f Cells ◽  
Receptor Number ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Insulinoma Cells ◽  
Camp Formation ◽  
Rat Insulinoma ◽  
Stimulation Of

ABSTRACT The effect of dexamethasone on binding of glucagonlike peptide-1(7–36)amide (GLP-1(7–36)amide) to rat insulinoma-derived cells (RINm5F) was investigated. Preincubation of RINm5F cells with dexamethasone (100 nmol/l) for 24 h resulted in a decrease of GLP1(7-36)amide binding to 55·0±8·16% (mean ± s.e.m.), incubation for 48 h to 39·1±1·76%, and for 72 h to 15·5±4·35% of maximal binding. The GLP-1(7–36)amide-induced stimulation of cyclic AMP (cAMP) production was significantly decreased to 61·03±7·4% of maximum production in cells pretreated with dexamethasone (100 nmol/l) for 48 h. The decreased binding was due to a reduction of the receptor number while the receptor affinity remained unchanged. These inhibitory effects on binding and cAMP formation induced by dexamethasone were completely abolished when the antiglucocorticoid RU 38486 (100 nmol/l) was added during preincubation with dexamethasone. RU 38486 alone had no effects. Our data suggest that the biological action of GLP-1(7–36) amide at the B-cell may be modified by glucocorticoids. Journal of Endocrinology (1990) 126, 445–450

scholarly journals Increased glucose oxidation and contents of insulin and ATP in polyamine-depleted rat insulinoma cells (RINm5F)

1991 ◽  
Vol 277 (2) ◽  
pp. 533-540 ◽  
Author(s):  
A Sjöholm ◽  
N Welsh ◽  
V Hoftiezer ◽  
P W Bankston ◽  
C Hellerström
Keyword(s):  
Total Protein ◽  
Glucose Oxidation ◽  
Total Protein Content ◽  
Cell Nuclei ◽  
Rinm5f Cells ◽  
Electron Microscopic ◽  
Insulin Synthesis ◽  
Insulinoma Cells ◽  
The Impact ◽  
Rat Insulinoma

In order to elucidate the role of polyamines in the replication and insulin production of insulin-secreting cells, we have investigated the impact of partial polyamine depletion on the proliferation, metabolism, insulin synthesis and ultrastructure of clonal rat insulinoma cells (RINm5F). For this purpose RINm5F cells were exposed for 4 days to the specific ornithine decarboxylase (ODC) inhibitor difluoromethylornithine (DFMO). This resulted in a profound decrease in ODC activity and cytoplasmic polyamine contents. The polyamine content of cell nuclei was, however, not altered by DFMO. Addition of small amounts of putrescine during culture elevated the intracellular content of this diamine and suppressed ODC activity. The decrease in polyamine contents was accompanied by a pronounced inhibition of the cellular proliferative activity. The rates of glucose utilization, oxygen uptake and activity of the pentose cycle were decreased in DFMO-treated cells, whereas the glucose oxidation rate, oxidation/utilization ratio, ATP content and ATP/ADP ratio were increased. Insulin mRNA content and synthesis of proinsulin, insulin and total protein were not altered by DFMO. In contrast, there was a sizeable increase in the cellular insulin content, despite a lowered total protein content. Electron-microscopic analysis revealed an accumulation of insulin-secretion granules in the DFMO-treated cells. In addition, short-term insulin release was increased after DFMO exposure, but was not rendered glucose-sensitive. It is concluded that polyamines are necessary for the maintenance of rapid insulinoma-cell replication and that DFMO-treated RINm5F cells acquire an enhanced substrate oxidation and increased content of insulin and ATP.

Binding sites for peptide-histidine-isoleucine (PHI) on rat insulinoma-derived RINm5F cells

1988 ◽  
Vol 60 (2-3) ◽  
pp. 211-215 ◽  
Author(s):  
Rüdiger Göke ◽  
J.Michael Conlon
Keyword(s):  
Binding Sites ◽  
Rinm5f Cells ◽  
Rat Insulinoma

KCl-induced insulin secretion from RINm5F cells is mediated through Ca2+ influx along L-type Ca2+ channels

1992 ◽  
Vol 346 (5) ◽  
Author(s):  
M. Roenfeldt ◽  
H. Safayhi ◽  
H.P.T. Ammon
Keyword(s):  
Insulin Secretion ◽  
Rinm5f Cells ◽  
Ca2 Channels

The imidazoline derivative calmidazolium inhibits voltage-gated Ca2+-channels and insulin release but has no effect on the phospholipase C system in insulin producing RINm5F-cells

1994 ◽  
Vol 14 (3) ◽  
pp. 145-158 ◽  
Author(s):  
Henrik Kindmark ◽  
Martin Köhler ◽  
Pär Gerwins ◽  
Olof Larsson ◽  
Akhtar Khan ◽  
...  
Keyword(s):  
Insulin Release ◽  
Hormone Secretion ◽  
Rinm5f Cells ◽  
Calmodulin Antagonist ◽  
Voltage Gated ◽  
Mechanism Of Inhibition ◽  
Dependent Protein ◽  
Direct Binding ◽  
Ca2 Channels ◽  
Imidazoline Derivative

The present study shows that the calmodulin antagonist calmidazolium inhibited influx of Ca2+ through voltage-gated Ca2+-channels in clonal insulin producing RINm5F-cells. The mechanism of inhibition may involve both Ca2+-calmodulin-dependent protein kinases and direct binding of calmidazolium to the Ca2+-channel. Calmidazolium did not affect uptake of Ca2+ into intracellular Ca2+-pools, inositol 1,4,5-trisphosphate (InsP3) formation or action on intracellular Ca2+-pools. The calmodulin inhibitor also did not affect glucose utilization or oxidation in RINm5F-cells, speaking against an unspecific toxic effect of the compound. KCl-and ATP-stimulated insulin release from RINm5F-cells was attenuated by calmidazolium, whereas basal hormone secretion was unaffected.

Glucagon-like peptide-1(7–36)amide: characterization of the domain responsible for binding to its receptor on rat insulinoma RINm5F cells

1990 ◽  
Vol 5 (1) ◽  
pp. 33-39 ◽  
Author(s):  
B. Gallwitz ◽  
W. E. Schmidt ◽  
J. M. Conlon ◽  
W. Creutzfeldt
Keyword(s):  
Cyclic Amp ◽  
Rinm5f Cells ◽  
Binding Studies ◽  
Rinm5f Cell ◽  
Radiation Induced ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Dose Dependent ◽  
Rat Insulinoma

ABSTRACT Glucagon-like peptide-1(7–36)amide (GLP-1(7–36)amide) is a potent stimulator of insulin secretion. Receptors for this hormone have been found on different insulinoma-derived cell lines, e.g. the RINm5F cell line which is derived from a radiation-induced rat insulinoma. To characterize the part of the GLP-1(7–36)amide molecule that is responsible for binding to its receptor on RINm5F cells, binding studies with synthetic C-terminal (GLP-1(21–36)amide) and synthetic N-terminal (GLP-1(7–25)) GLP-1 fragments were carried out. GLP-1(21–36)amide showed dose-dependent binding to the GLP-1(7–36)amide receptor but was approximately 1500 times less potent in inhibiting binding of 125I-labelled GLP-1(7–36)amide than the intact hormone. GLP-1(7–25) at concentrations up to 10 μmol/l did not inhibit binding of label. Neither fragment changed intracellular cyclic AMP concentrations, in contrast to GLP-1(7–36)amide which increased intracellular cyclic AMP. GLP-1(21–36)amide, however, acted as a weak partial antagonist of GLP-1(7–36)amide with respect to GLP-1(7–36)amide-dependent stimulation of cyclic AMP production.

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