Internalization of glucagon-like peptide-1(7–36)amide in rat insulinoma cells

1989 ◽  
Vol 189 (4) ◽  
pp. 257-264 ◽  
Author(s):  
R. Göke ◽  
G. Richter ◽  
B. Göke ◽  
M. Trautmann ◽  
R. Arnold
Keyword(s):  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Insulinoma Cells ◽  
Rat Insulinoma

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

Effects of Glucagon-Like Peptide-1 (GLP-1) in RINm5F Insulinoma Cells

2009 ◽  
Vol 103 (S 02) ◽  
pp. 31-36 ◽  
Author(s):  
P. M. Jehle ◽  
D. Jehle ◽  
R. D. Fußgänger ◽  
G. Adler
Keyword(s):  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Insulinoma Cells

scholarly journals Agonist-induced internalization and recycling of the glucagon-like peptide-1 receptor in transfected fibroblasts and in insulinomas

1995 ◽  
Vol 310 (1) ◽  
pp. 203-214 ◽  
Author(s):  
C Widmann ◽  
W Dolci ◽  
B Thorens
Keyword(s):  
Plasma Membrane ◽  
Pancreatic Beta Cell ◽  
Chinese Hamster ◽  
Lung Fibroblasts ◽  
Continuous Exposure ◽  
Agonist Binding ◽  
Receptor Endocytosis ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Insulinoma Cells

Glucagon-like peptide-1 (GLP-1) is the most potent stimulator of glucose-induced insulin secretion and its pancreatic beta-cell receptor is a member of a new subfamily of G-protein-coupled receptors which includes the receptors for vasoactive intestinal polypeptide, secretin and glucagon. Here we studied agonist-induced GLP-1 receptor internalization in receptor-transfected Chinese hamster lung fibroblasts using three different approaches. First, iodinated GLP-1 bound at 4 degrees C to transfected cells was internalized with a t 1/2 of 2-3 min following warming up of the cells to 37 degrees C. Secondly, exposure to GLP-1 induced a shift in the distribution of the receptors from plasma membrane-enriched to endosomes-enriched membrane fractions, as assessed by Western blot detection of the receptors using specific antibodies. Thirdly, continuous exposure of GLP-1 receptor-expressing cells to iodinated GLP-1 led to a linear accumulation of peptide degradation products in the medium following a lag time of 20-30 min, indicating a continuous cycling of the receptor between the plasma membrane and endosomal compartments. Potassium depletion and hypertonicity inhibited transferrin endocytosis, a process known to occur via coated pit formation, as well as GLP-1 receptor endocytosis. In contrast to GLP-1, the antagonist exendin-(9-39) did not lead to receptor endocytosis. Surface re-expression following one round of GLP-1 receptor endocytosis occurred with a half-time of about 15 min. The difference in internalization and surface re-expression rates led to a progressive redistribution of the receptor in intracellular compartments upon continuous exposure to GLP-1. Finally, endogenous GLP-1 receptors expressed by insulinoma cells were also found to be internalized upon agonist binding. Together our data demonstrate that the GLP-1 receptor is internalized upon agonist binding by a route similar to that taken by single transmembrane segment receptors. The characterization of the pathway and kinetics of GLP-1-induced receptor endocytosis will be helpful towards understanding the role of internalization and recycling in the control of signal transduction by this receptor.

Characterization of the receptor for glucagon-like peptide-1(7–36)amide on plasma membranes from rat insulinoma-derived cells by covalent cross-linking

1989 ◽  
Vol 2 (2) ◽  
pp. 93-98 ◽  
Author(s):  
R. Göke ◽  
T. Cole ◽  
J. M. Conlon
Keyword(s):  
Ligand Binding ◽  
Protein Complex ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Binding Protein ◽  
Single Class ◽  
Intact Cells ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Rat Insulinoma

ABSTRACT 125I-Labelled glucagon-like peptide-1(7–36)amide was cross-linked to a specific binding protein in plasma membranes prepared from RINm5F rat insulinoma-derived cells using disuccinimidyl suberate. Consistent with the presence of a single class of binding site on the surface of intact cells, only a single radiolabelled band at Mr 63 000 was identified by SDS-PAGE after solubilization of the ligand—binding protein complex. The band was not observed when 10 nm glucagon-like peptide-1(7–36)amide was included in the binding assay, but 1 μm concentrations of glucagon-like peptide1(1–36)amide, glucagon-like peptide-2 and glucagon did not decrease the intensity of labelling. No change in the mobility of the band was observed under reducing conditions, suggesting that the binding protein in the receptor is not attached to other subunits via disulphide bonds. In control incubations using plasma membranes from pig intestinal epithelial cells, which do not contain specific binding sites for glucagon-like peptide-1(7–36)amide, no cross-linked ligand-binding protein complex was observed.

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