Diabetes, Vol 36, Issue 11 1336-1340, Copyright © 1987 by American Diabetes Association

ARTICLES

Evidence of functional gastric inhibitory polypeptide (GIP) receptors in human insulinoma. Binding of synthetic human GIP 1-31 and activation of adenylate cyclase

M Maletti, JJ Altman, DH Hoa, M Carlquist and G Rosselin
Fondation de Recherche en Hormonologie, Fresnes, France.

Specific gastric inhibitory polypeptide (GIP) receptors were characterized in human benign insulinoma plasma membranes employing [mono-[125I]iodo-Tyr10]-GIP (125I-GIP) as the radioligand. GIP 1-42 inhibited 125I-GIP binding with an IC50 value of 10(-9) M. Scatchard analysis showed two classes of binding sites: a high-affinity site (Kd = 2.23 x 10(-10) M; Bmax = 24 fmol/mg protein) and a low-affinity site (Kd = 8.39 x 10(-9) M; Bmax = 118 fmol/mg protein). A synthetic replicate of human GIP 1-31 inhibited 125I-GIP binding with an IC50 value of 10(-8) M. The GIP binding sites of human insulinoma were coupled to adenylate cyclase stimulation. GIP 1-31 regulated the adenylate cyclase activity to the same extent as GIP 1-42. The concentrations of GIP required for maximal activity ranged from 10(-9) to 10(-8) M for either GIP 1-42 or GIP 1-31. The existence of functional GIP receptors in human insulinoma substantiates our recent reports demonstrating the presence of GIP binding sites in transplantable hamster insulinoma and indicates that GIP could exert a direct control of the beta-cell function in humans through a purely endocrine pathway.
CiteULike    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. Zhou, M. F. A. Livak, M. Bernier, D. C. Muller, O. D. Carlson, D. Elahi, S. Maudsley, and J. M. Egan Ubiquitination is involved in glucose-mediated downregulation of GIP receptors in islets Am J Physiol Endocrinol Metab, August 1, 2007; 293(2): E538 - E547. [Abstract] [Full Text] [PDF]

				C. F. Deacon, A. Plamboeck, M. M. Rosenkilde, J. de Heer, and J. J. Holst GIP-(3-42) does not antagonize insulinotropic effects of GIP at physiological concentrations Am J Physiol Endocrinol Metab, September 1, 2006; 291(3): E468 - E475. [Abstract] [Full Text] [PDF]

				L Marenah, P R Flatt, D F Orr, C Shaw, and Y H A Abdel-Wahab Skin secretions of Rana saharica frogs reveal antimicrobial peptides esculentins-1 and -1B and brevinins-1E and -2EC with novel insulin releasing activity J. Endocrinol., January 1, 2006; 188(1): 1 - 9. [Abstract] [Full Text] [PDF]

				M. B. Wheeler, R. W. Gelling, S. A. Hinke, B. Tu, R. A. Pederson, F. Lynn, J. Ehses, and C. H. S. McIntosh Characterization of the Carboxyl-terminal Domain of the Rat Glucose-dependent Insulinotropic Polypeptide (GIP) Receptor. A ROLE FOR SERINES 426 AND 427 IN REGULATING THE RATE OF INTERNALIZATION J. Biol. Chem., August 27, 1999; 274(35): 24593 - 24601. [Abstract] [Full Text] [PDF]

				N. N’Diaye, J. Tremblay, P. Hamet, W. W. De Herder, and A. Lacroix Adrenocortical Overexpression of Gastric Inhibitory Polypeptide Receptor Underlies Food-Dependent Cushing's Syndrome J. Clin. Endocrinol. Metab., August 1, 1998; 83(8): 2781 - 2785. [Abstract] [Full Text]