Glucose-dependent insulinotropic polypeptide: difference between revisions
Diff·revision 10 → 11·01:51, 1 Aug 2024
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| 10 | GIP is processed post-translationally from pro-GIP and circulates in two forms: the active GIP (1–42) and an N-terminally cleaved GIP (3–42) produced by dipeptidyl peptidase-4 cleavage. Both forms retain insulin-secretory activity, which is unusual among incretin peptides and is the basis for the ''glucose-dependent'' descriptor — GIP potentiates insulin secretion only when glucose is elevated.{{r|deacon1995}} | 10 | GIP is processed post-translationally from pro-GIP and circulates in two forms: the active GIP (1–42) and an N-terminally cleaved GIP (3–42) produced by dipeptidyl peptidase-4 cleavage. Both forms retain insulin-secretory activity, which is unusual among incretin peptides and is the basis for the ''glucose-dependent'' descriptor — GIP potentiates insulin secretion only when glucose is elevated.{{r|deacon1995}} |
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| + | 12 | The historical naming reflects its dual function: it inhibits gastric acid secretion (the basis of the original acronym, ''glucose-dependent insulinotropic peptide'') and amplifies postprandial insulin secretion. In type 2 diabetes, the insulinotropic arm of GIP is impaired, whereas the GLP-1 arm remains partly intact, which is why [[GLP-1 receptor agonist|GLP-1-directed therapies]] were developed first. The later discovery that dual GIP/GLP-1 receptor agonism produces greater clinical benefit than GLP-1 monotherapy has reestablished GIP as a therapeutic target.{{r|frias2021}} | |
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| 12 | == Biosynthesis and secretion == | 14 | == Biosynthesis and secretion == |
| 13 | GIP is encoded by the ''GIP'' gene and is processed from a 153-residue pro-GIP. Like GLP-1, it is subject to tissue-specific post-translational modification. In K cells, endopeptidases cleave pro-GIP to release the active hormone. The principal stimuli are glucose and long-chain fatty acids; amino acids are a weaker stimulus.{{r|nauck2019}} | 15 | GIP is encoded by the ''GIP'' gene and is processed from a 153-residue pro-GIP. Like GLP-1, it is subject to tissue-specific post-translational modification. In K cells, endopeptidases cleave pro-GIP to release the active hormone. The principal stimuli are glucose and long-chain fatty acids; amino acids are a weaker stimulus.{{r|nauck2019}} |
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| 19 | <ref name="nauck2019">Nauck MA. "Incretin hormones: Their role in health and disease." ''Diabetes, Obesity and Metabolism'' 20 Suppl 1:4–21 (2018). DOI:10.1111/dom.13129. PMID 29364588.</ref> | 21 | <ref name="nauck2019">Nauck MA. "Incretin hormones: Their role in health and disease." ''Diabetes, Obesity and Metabolism'' 20 Suppl 1:4–21 (2018). DOI:10.1111/dom.13129. PMID 29364588.</ref> |
| 20 | <ref name="deacon1995">Deacon CF, Johnsen AH, Holst JJ. "Degradation of glucose-dependent insulinotropic polypeptide by human plasma in vitro yields an N-terminally truncated peptide that is a major endogenous metabolite in vivo." ''Journal of Clinical Endocrinology and Metabolism'' 80(3):952–957 (1995). PMID 7883856.</ref> | 22 | <ref name="deacon1995">Deacon CF, Johnsen AH, Holst JJ. "Degradation of glucose-dependent insulinotropic polypeptide by human plasma in vitro yields an N-terminally truncated peptide that is a major endogenous metabolite in vivo." ''Journal of Clinical Endocrinology and Metabolism'' 80(3):952–957 (1995). PMID 7883856.</ref> |
| + | 23 | <ref name="frias2021">Frías JP, Davies MJ, Rosenstock J, et al. "Tirzepatide versus semaglutide oral in type 2 diabetes." ''New England Journal of Medicine'' 385(6):503–515 (2021). DOI:10.1056/NEJMoa2107519. PMID 34170647.</ref> | |
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| 22 | {{DEFAULTSORT:Glucose-dependent insulinotropic polypeptide}} | 25 | {{DEFAULTSORT:Glucose-dependent insulinotropic polypeptide}} |