Potency and specificity of GRA1 in vitro.

GCGR = glucagon receptor.GIPR = glucose-dependent insulinotropic peptide receptor.GLP-1R = GLP-1 receptor.PAC1R = pituitary adenylate cyclase-activating polypeptide receptor type 1.VPAC2R = vasoactive adenylate cyclase-activating polypeptide receptor type 2.aInhibition of binding between 125I-glucagon and the hGCGR was measured in membranes prepared from CHO cells expressing hGCGR. Inhibition of cAMP production was measured in intact CHO cells stably expressing human GCGR, GIPR, GLP-1R, PAC1R, and VPAC2R and stimulated by their respective agonists, glucagon, GIP, GLP-1, PAC1, and VPAC2.