| First Author | Fujita Y | Year | 2010 |
| Journal | Am J Physiol Gastrointest Liver Physiol | Volume | 298 |
| Issue | 5 | Pages | G608-14 |
| PubMed ID | 20185691 | Mgi Jnum | J:159247 |
| Mgi Id | MGI:4442125 | Doi | 10.1152/ajpgi.00024.2010 |
| Citation | Fujita Y, et al. (2010) Differential processing of pro-glucose-dependent insulinotropic polypeptide in gut. Am J Physiol Gastrointest Liver Physiol 298(5):G608-14 |
| abstractText | Glucose-dependent insulinotropic polypeptide (GIP) is a hormone released from enteroendocrine K cells in response to meals. Posttranslational processing of the precursor protein pro-GIP at residue 65 by proprotein convertase subtilisin/kexin type 1 (PC1/3) in gut K cells gives rise to the established 42-amino-acid form of GIP (GIP(1-42)). However, the pro-GIP peptide sequence contains a consensus cleavage site for PC2 at residues 52-55 and we identified PC2 immunoreactivity in a subset of K cells, suggesting the potential existence of a COOH-terminal truncated GIP isoform, GIP(1-30). Indeed a subset of mouse and human K cells display GIP immunoreactivity with GIP antibodies directed to the mid portion of the peptide, but not with a COOH-terminal-directed GIP antibody, indicative of the presence of a truncated form of GIP. This population of cells represents approximately 5-15% of the total GIP-immunoreactive cells in mice, depending on the region of intestine, and is virtually absent in mice lacking PC2. Amidated GIP(1-30) and GIP(1-42) have comparable potency at stimulating somatostatin release in the perfused mouse stomach. Therefore, GIP(1-30) represents a naturally occurring, biologically active form of GIP. |
