GLP-1 receptors in golden Syrian hamster islets: identification and functional characterization.
This study aims at the identification and functional characterization of glucagon-like peptide 1 (7-36) amide (GLP-1) receptor in islets from Golden Syrian hamsters. Using a polyclonal antibody against rat GLP-1 receptors, Western blotting of the islet proteins revealed two major bands of 44 and 70 kDa, similar to those found in rat islets, RINm5F cells, and HIT-T15 cells. In Northern blots, transcripts of 2.7, 3.6 and 3.7 kb were observed in rat islets and RINm5F cells after hybridization with rat GLP-1 receptor cDNA probes of either 21 9 bp or 1.5 kb. Such was not the case in either hamster islets or HIT-T15 cells. However, a single 3.6-kb transcript was observed in the latter two cases when a human GLP-1 receptor cDNA probe of 1.6 kb was used for hybridization. In the isolated perfused pancreas of Golden Syrian hamsters, a rise in D-glucose concentration from 3.3 to 8.3 mM caused a biphasic stimulation of insulin release, which was further increased by either GLP-1 or glucagon (10(-9)M each). The enhancing action of GLP-1 on glucose-stimulated insulin secretion was much more marked than that of glucagon. The rise in D-glucose concentration decreased by 46+/-4% the release of glucagon, but GLP-1 failed to exert any obvious effect on glucagon secretion in the presence of 8.3 mM D-glucose. These results indicate that GLP-1 receptors are expressed in islets of Golden Syrian hamsters with an extracellular part possessing the same immunoreactivity as the rat islet GLP-1 receptors. The expression of the mRNA for the GLP-1 receptor differs, however, from that found in rat or human islets.
Rosselin
G
G
Unité de Recherches sur les Peptides Neurodigestifs et le Diabète, Institut National de la Santé et de la Recherche Médicale U55, Centre de Recherches Paris-Saint-Antoine, Paris, France.
Leclercq-Meyer
V
V
Boissart
C
C
Pessah
M
M
Malaisse
W J
WJ
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D006224:Cricetinae; D005260:Female; D005934:Glucagon / Q000378:metabolism / Q000494:pharmacology; D052216:Glucagon-Like Peptide 1; D000067757:Glucagon-Like Peptide-1 Receptor; D004763:Glucagon-Like Peptides; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008647:Mesocricetus; D010446:Peptide Fragments; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D018027:Receptors, Glucagon / Q000378:metabolism*
C000593833:GLP1R protein, human; C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D007328:Insulin; D010446:Peptide Fragments; D010455:Peptides; D018027:Receptors, Glucagon; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; C051322:glucagon-like peptide 1 (7-37)