Receptors for glucagon-like peptide-1(7–36) amide on rat insulinoma-derived cells

Abstract

Specific binding of 125I-labelled glucagon-like peptide-1(7-36)amide (GLP-1(7-36)amide) to rat insulinoma-derived RINm5F cells was dependent upon time and temperature and was proportional to cell concentration. Binding of radioactivity was inhibited in a concentration-dependent manner by GLP-1(7-36) amide consistent with the presence of a single class of binding site with a dissociation constant (Kd) of 204 +/- 8 pmol/l (mean +/- S.E.M.). Binding of the peptide resulted in a dose-dependent increase in cyclic AMP concentrations (half maximal response at 250 +/- 20 pmol/l). GLP-1(1-36)amide was approximately 200 times less potent than GLP-1(7-36)amide in inhibiting the binding of 125I-labelled GLP-1(7-36)amide to the cells (Kd of 45 +/- 6 nmol/l). Binding sites for GLP-1 (7-36)amide were not present on dispersed enterocytes from porcine small intestine.

Molecular cloning, functional expression, and signal transduction of the GIP‐receptor cloned from a human insulinoma

“…'25I-labeled GIP-1-30 was prepared as earlier described [8]. The specific activity of the tracer was approx.…”

International Union of Pharmacology. XXXV. The Glucagon Receptor Family

“…Analysis of data obtained from binding experiments with RINm5F cells revealed that GLP-1 binds to a single class of binding sites (Goke and Conlon, 1988). Crosslinking studies with 125 I-GLP-1 demonstrate a single band with an apparent molecular mass of 63,000 (Goke et al, 1989a(Goke et al, , 1992.…”

“…GLP-1 receptors were first identified by a combination of radioligand binding experiments and measurements of cyclic AMP accumulation using rat insulinoma-derived RIN1046-38 cells (Drucker et al, 1987;Goke and Conlon, 1988) followed by localization on additional rodent insulinoma cell lines (Fehmann et al, 1995a) as well as on rat (Moens et al, 1996) and human (Fehmann et al, 1995b) pancreatic islet ␤-cells and somatostatinsecreting cells (Fehmann and Habener, 1991;Gros et al, 1992). GLP-1 binding sites have also been identified on isolated rat gastric parietal cells (Uttenthal and Blazquez, 1990;Schmidtler et al, 1994), human gastric cancer cells (HGT-1) (Hansen et al, 1988), solubilized membranes of rat epididymal adipose tissue (Valverde et al, 1993), 3T3-L1 adipocytes (Montrose-Rafizadeh et al, 1997), membranes from the rodent thyrotrope cell line ␣-TSH , and in rat lung (Richter et al, 1990(Richter et al, , 1991 and brain (Shimizu et al, 1987;Uttenthal and Blazquez, 1990;Goke et al, 1995;Wei and Mojsov, 1995).…”

“…Radioligand assays were used to characterize binding at the endogenous receptor expressed in rat insulinoma cell lines (Goke and Conlon, 1988;Fehmann et al, 1995a), recombinant receptors expressed in transfected COS cells (Thorens, 1992;Thorens et al, 1993) or transfected Chinese hamster lung fibroblast (rCHL) cells (Van Eyll et al, 1994). Homologous desensitization and internalization of the GLP-1 receptor is strictly dependent on the phosphorylation of three serine doublets within the cytoplasmic tail (Widmann et al, 1997).…”

Identification and characterization of glucagon‐like peptide‐1 7–36 amide‐binding sites in the rat brain and lung

“…GLP-1 7-36 NH2 occurs naturally, and is a potent stimulator of insulin secretion in the isolated rat pancreas [7], a rat ~-cell line [3], and the most potent insulinotropic hormone known in man [6]. The existence of GLP-1 7-36 NHz receptors in rat [8,9]. Recently we have reported the presence of GLP-1 7-36 NH2 in the brain [10].…”