Insulin secretion: difference between revisions
Diff·revision 4 → 5·05:15, 15 Sep 2024
Difference between revision 4 and revision 5 of Insulin secretion. 2 lines changed; the page grew by 352 bytes.
| Revision 4 — 00:03, 29 Aug 2024 SatietySunniva (talk) move the trial material out of §Physiology into the compound articles 2,360 bytes ±0 | Revision 5 — 05:15, 15 Sep 2024 DeadSpaceDot (talk) the numbers in the lead disagreed with the body; body was right 2,712 bytes +352 | ||
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| 10 | The distinction between triggering and amplifying pathways is the single most important idea for understanding why [[GLP-1 receptor agonist|GLP-1 receptor agonists]] rarely cause [[Hypoglycaemia|hypoglycaemia]] while sulfonylureas frequently do. Sulfonylureas act on the triggering pathway and initiate secretion regardless of glucose; incretins act on the amplifying pathway and can only enlarge a response that glucose has already begun.{{r|drucker2018}} | 10 | The distinction between triggering and amplifying pathways is the single most important idea for understanding why [[GLP-1 receptor agonist|GLP-1 receptor agonists]] rarely cause [[Hypoglycaemia|hypoglycaemia]] while sulfonylureas frequently do. Sulfonylureas act on the triggering pathway and initiate secretion regardless of glucose; incretins act on the amplifying pathway and can only enlarge a response that glucose has already begun.{{r|drucker2018}} |
| 11 | 11 | ||
| + | 12 | Secretion is biphasic. A first phase lasting some ten minutes reflects release of a small pool of vesicles already docked at the membrane; a sustained second phase reflects recruitment and priming of further vesicles. Loss of first-phase secretion is among the earliest detectable abnormalities in the progression to type 2 diabetes.{{r|rorsman2013}} | |
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| 12 | == The triggering pathway == | 14 | == The triggering pathway == |
| 13 | Glucose enters the beta cell through GLUT1 and GLUT3 transporters and is phosphorylated by glucokinase, whose kinetics — a high {{math|K_m}} near 8 mM and no product inhibition — make it the rate-limiting step and the cell's effective glucose sensor. Subsequent glycolysis and mitochondrial oxidation raise the cytosolic ATP:ADP ratio.{{r|rorsman2013}} | 15 | Glucose enters the beta cell through GLUT1 and GLUT3 transporters and is phosphorylated by glucokinase, whose kinetics — a high {{math|K_m}} near 8 mM and no product inhibition — make it the rate-limiting step and the cell's effective glucose sensor. Subsequent glycolysis and mitochondrial oxidation raise the cytosolic ATP:ADP ratio.{{r|rorsman2013}} |