Glucose-dependent insulinotropic polypeptide: difference between revisions
Diff·revision 6 → 7·13:32, 28 Aug 2024
Difference between revision 6 and revision 7 of Glucose-dependent insulinotropic polypeptide. 5 lines changed; the page grew by 829 bytes.
| Revision 6 — 10:46, 11 Aug 2024 LCellLeif (talk) the numbers in the lead disagreed with the body; body was right 3,517 bytes +149 | Revision 7 — 13:32, 28 Aug 2024 ReceptorRhoda (talk) attribute the gastric-emptying effect to the study that measured it 4,346 bytes +829 | ||
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| 21 | K cells are found predominantly in the duodenum and jejunum, extending into the ileum in smaller numbers. They are open-type epithelial cells with an apical surface exposed to the lumen, allowing direct contact with nutrient-induced secretagogues. Secretion is biphasic: an early phase within 15 minutes of ingestion, followed by a later more sustained phase as nutrients pass through the intestine.{{r|nauck2019}} | 21 | K cells are found predominantly in the duodenum and jejunum, extending into the ileum in smaller numbers. They are open-type epithelial cells with an apical surface exposed to the lumen, allowing direct contact with nutrient-induced secretagogues. Secretion is biphasic: an early phase within 15 minutes of ingestion, followed by a later more sustained phase as nutrients pass through the intestine.{{r|nauck2019}} |
| 22 | 22 | ||
| + | 23 | Fasting concentrations of total GIP in healthy adults are typically 40–60 pmol/L, rising 5–10-fold postprandially. The response to glucose is monophasic, reaching a peak around 30–60 minutes after a meal. This distinct timing profile — earlier than GLP-1 and independent of the distal small intestine — means GIP is the first incretin to encounter the portal circulation. | |
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| + | 25 | == Receptor signalling and cellular actions == | |
| + | 26 | GIP acts through the GIP receptor (GIPR), a class B G-protein-coupled receptor structurally related to [[GLP-1 receptor|the GLP-1 receptor]]. Like GLP-1, GIP coupling is glucose-dependent at the beta cell: the same concentration of GIP that stimulates insulin secretion at 8 mM glucose is ineffective at 2 mM, the physiological basis for avoiding hypoglycaemia in the fasting state.{{r|frias2021}} | |
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| 23 | == References == | 28 | == References == |
| 24 | {{reflist}} | 29 | {{reflist}} |