Actions of GIP

Evolutionarily Conserved Residues at Glucagon-like Peptide-1 (GLP-1) Receptor Core Confer Ligand-induced Receptor Activation

“…Another incretin, glucose-dependent insulinotropic polypeptide (GIP) is a 42-amino acid hormone that is produced by enteroendocrine K-cells (4). Like GLP-1, GIP stimulates insulin secretion in a glucose-dependent manner (5). GIP regulates lipid metabolism through direct actions on adipose tissues and is involved in bone formation through stimulation of osteoblast proliferation and inhibition of apoptosis (6).…”

Human and porcine immunoreactive gastric inhibitory polypeptides (IR‐GIP) are not identical

“…GIP is a 42 amino acid polypeptide hormone which has been known as both gastric acid inhibitory polypeptide [l] and glucose-dependent insulinotropic polypeptide [2,3]. The polypeptide was initially isolated from porcine upper small intestine [4] where it has been localised to a discrete endocrine cell type called the K cell [S].…”

Glucose-dependent Insulinotropic Polypeptide (GIP): Development of DP IV-Resistant Analogues with Therapeutic Potential

“…A peptide corresponding to GIP was identified and it was suggested that enzymatic cleavage resulted in formation of the N-terminally truncated molecule 11 . GIP was shown to be non-insulinotropic in the perfused rat pancreas 10 and isolated islets. Mentlein et al 12 first reported that GIP 1-42 was a substrate for DPIV, with release of Tyr 1 -Ala 2 .…”

“…therapeutic use are that it is rapidly degraded in the bloodstream and that type 2 diabetic patients exhibit resistance to GIP action. The first indication that GIP was a target for DPIV degradation was obtained in HPLC studies on partially purified fractions from porcine intestinal extracts 10 . A peptide corresponding to GIP 3-42 was identified and it was suggested that enzymatic cleavage resulted in formation of the N-terminally truncated molecule 11 .…”

“…Recently, we obtained evidence for a bioactive domain of GIP residing in residues 1-14 20 . In binding studies, bioactivity of Nterminal GIP fragments was restricted to GIP [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and amidated forms of GIP [1][2][3][4][5][6][7][8][9][10][11][12][13] and GIP [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] . GIP 1-14NH2 exhibits low, but significant, insulinotropic activity.…”