Ligand-specificity of the rat GLP-I receptor recombinantly expressed in Chinese hamster ovary (CHO-) cells.
Glucagon-like peptide-I (GLP-I) is a potent incretin hormone and is considered as a new therapeutic tool in the treatment of diabetes mellitus. This study was designed to precisely characterize the binding behavior and activation of the recombinant GLP-I receptor against naturally occurring ligands of the glucagon/VIP/secretin peptide hormone family. CHO-cells were stably transfected with a plasmid containing a cDNA encoding for the rat GLP-I receptor. Northern blot analysis with this cDNA showed a single band of 2.7 kb in CHO cells, while in RINm5F cells, three bands of 2.7, 3.4, and 3.6 kb were specifically labelled. In receptor-binding studies 125I-GLP-I was displaced by GLP-I and weakly by PHI and oxyntomodulin but not by helodermin, helospectin I, helospectin II, secretin, VIP, and PACAP-38. Intracellular cAMP generation was stimulated by GLP-I, PHI, and oxyntomodulin. Helodermin, helospectin I, helospectin II, secretin, VIP, and PACAP-38 were not able to displace 125I-GLP-I from its receptor or to stimulate intracellular cAMP production. This data shows that the GLP-I receptor is characterized by a high ligand specificity.
Department of Medicine, Philipps-University of Marburg.
H C
HC
Fehmann
J
J
Jiang
J
J
Schweinfurth
K
K
Dörsch
M B
MB
Wheeler
A E
AE
Boyd
B
B
Göke
D000818:Animals; D015152:Blotting, Northern; D016466:CHO Cells; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D005934:Glucagon / Q000235:genetics*; D052216:Glucagon-Like Peptide 1; D000067757:Glucagon-Like Peptide-1 Receptor; D010446:Peptide Fragments / Q000235:genetics*; D011498:Protein Precursors / Q000235:genetics*; D051381:Rats; D011956:Receptors, Cell Surface / Q000235:genetics*; D018027:Receptors, Glucagon; D011994:Recombinant Proteins; D014162:Transfection / Q000235:genetics*
C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D010446:Peptide Fragments; D011498:Protein Precursors; D011956:Receptors, Cell Surface; D018027:Receptors, Glucagon; D011994:Recombinant Proteins; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D000242:Cyclic AMP