TY - JOUR
T1 - Identification of a bioactive domain in the amino-terminus of glucose-dependent insulinotropic polypeptide (GIP)
AU - Hinke, Simon A.
AU - Manhart, Susanne
AU - Pamir, Nathalie
AU - Demuth, Hans Ulrich
AU - W. Gelling, Richard
AU - Pederson, Raymond A.
AU - McIntosh, Christopher H.S.
N1 - Funding Information:
This work was funded in part by the Department of Science and Technology of Sachsen Anhalt (H.U.D. and S.M., Grant number 9704/00116) and by the Medical Research Council of Canada (C.H.S.M. and R.A.P., Grant number 590007) and the Canadian Diabetes Association. S.A.H. is funded by the Medical Research Council of Canada and the Killam Trusts. We are grateful for the technical assistance of Cuilan Nian and Irene Bremsak.
PY - 2001/5/5
Y1 - 2001/5/5
N2 - The incretins are a class of hormones released from the small bowel that act on the endocrine pancreas to potentiate insulin secretion in a glucose-dependent manner. Due to the requirement for an elevated glucose concentration for activity, the incretins, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1, have potential in the treatment of non-insulin-dependent diabetes mellitus. A series of synthetic peptide GIP fragments was generated for the purpose of elucidating the bioactive domain of the molecule. Peptides were screened for stimulation of cyclic AMP (cAMP) accumulation in Chinese hamster ovary cells transfected with the rat islet GIP receptor. Of the GIP fragments tested, GIP1-14 and GIP19-30 demonstrated the greatest cAMP-stimulating ability over the range of concentrations tested (up to 20 μM). In contrast, GIP fragments corresponding to amino acids 15-42, 15-30, 16-30 and 17-30 all demonstrated weak antagonism of GIP1-42 activity. Competitive-binding displacement studies indicated that these peptides were low-affinity ligands for the GIP receptor. To examine biological activity in vivo, a bioassay was developed in the anesthetized rat. Intravenous infusion of GIP1-42 (1 pmol/min/100 g) with a concurrent intraperitoneal glucose load (1 g/kg) significantly reduced circulating blood glucose excursions through stimulation of insulin release. Higher doses of GIP1-14 and GIP19-30 (100 pmol/min/100 g) also reduced blood glucose excursions.
AB - The incretins are a class of hormones released from the small bowel that act on the endocrine pancreas to potentiate insulin secretion in a glucose-dependent manner. Due to the requirement for an elevated glucose concentration for activity, the incretins, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1, have potential in the treatment of non-insulin-dependent diabetes mellitus. A series of synthetic peptide GIP fragments was generated for the purpose of elucidating the bioactive domain of the molecule. Peptides were screened for stimulation of cyclic AMP (cAMP) accumulation in Chinese hamster ovary cells transfected with the rat islet GIP receptor. Of the GIP fragments tested, GIP1-14 and GIP19-30 demonstrated the greatest cAMP-stimulating ability over the range of concentrations tested (up to 20 μM). In contrast, GIP fragments corresponding to amino acids 15-42, 15-30, 16-30 and 17-30 all demonstrated weak antagonism of GIP1-42 activity. Competitive-binding displacement studies indicated that these peptides were low-affinity ligands for the GIP receptor. To examine biological activity in vivo, a bioassay was developed in the anesthetized rat. Intravenous infusion of GIP1-42 (1 pmol/min/100 g) with a concurrent intraperitoneal glucose load (1 g/kg) significantly reduced circulating blood glucose excursions through stimulation of insulin release. Higher doses of GIP1-14 and GIP19-30 (100 pmol/min/100 g) also reduced blood glucose excursions.
KW - Adenylyl cyclase
KW - Bioassay
KW - Competitive binding
KW - Cyclic adenosine monophosphate
KW - Enteroinsular axis
KW - Perfused pancreas
KW - Structure-activity relationship
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U2 - 10.1016/S0167-4838(01)00181-9
DO - 10.1016/S0167-4838(01)00181-9
M3 - Article
C2 - 11343800
AN - SCOPUS:0035810678
SN - 0167-4838
VL - 1547
SP - 143
EP - 155
JO - Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
JF - Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
IS - 1
ER -