The incretin hormone glucose-dependent insulinotropic polypeptide (GIP) is rapidly degraded in the circulation by dipeptidyl peptidase IV forming the N-terminally truncated peptide GIP(3-42). The present study examined the biological activity of this abundant circulating fragment peptide to establish its possible role in GIP action. Human GIP and GIP(3-42) were synthesised by Fmoc solid-phase peptide synthesis, purified by HPLC and characterised by electrospray ionisation-mass spectrometry. In GIP receptor-transfected Chinese hamster lung fibroblasts, GIP(3-42) dose dependently inhibited GIP-stimulated (10(-7) M) cAMP production (up to 75.4 +/-5.4%; P
|Journal||Journal of Endrocrinology|
|Publication status||Published - Nov 2002|
Gault, V., Parker, JC., Harriott, P., Flatt, P., & O'Harte, F. (2002). Evidence that the major degradation product of glucose-dependent insulinotropic polypeptide, GIP(3-42), is a GIP receptor antagonist in vivo. Journal of Endrocrinology, 175(2), 525-533.