Beta cell function: difference between revisions
Diff·revision 2 → 3·22:22, 1 Sep 2024
Difference between revision 2 and revision 3 of Beta cell function. 5 lines changed; the page grew by 604 bytes.
| Revision 2 — 06:49, 31 Aug 2024 Chromatokid (talk) serial comma per PP:MOS 1,687 bytes ±0 | Revision 3 — 22:22, 1 Sep 2024 Chromatokid (talk) add the species in which the knockout work was done 2,291 bytes +604 | ||
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| 10 | The central methodological difficulty is that secretion and sensitivity are not independent. A healthy beta cell compensates for insulin resistance by secreting more, so an absolute secretion figure that looks normal may represent substantial dysfunction in a very insulin-resistant person. Measures that do not adjust for sensitivity — including fasting insulin and HOMA-B — are therefore weak, and the disposition index, the product of a secretion measure and a sensitivity measure, was devised to address exactly this.{{r|bergman2002}} | 10 | The central methodological difficulty is that secretion and sensitivity are not independent. A healthy beta cell compensates for insulin resistance by secreting more, so an absolute secretion figure that looks normal may represent substantial dysfunction in a very insulin-resistant person. Measures that do not adjust for sensitivity — including fasting insulin and HOMA-B — are therefore weak, and the disposition index, the product of a secretion measure and a sensitivity measure, was devised to address exactly this.{{r|bergman2002}} |
| 11 | 11 | ||
| + | 12 | == What is being measured == | |
| + | 13 | Insulin secretion cannot be sampled at source. Peripheral venous insulin has already passed the liver, which extracts a variable 40–80% at first pass, so peripheral concentration understates secretion by an amount that itself varies between people and with pulsatility.{{r|rorsman2013}} | |
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| + | 15 | [[C-peptide]] avoids this. It is co-secreted with insulin in equimolar amounts, is not extracted by the liver, and has predictable kinetics, so a peripheral C-peptide profile can be deconvolved into a secretion rate. This is the basis of every rigorous measure of beta-cell function. | |
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| 12 | == References == | 17 | == References == |
| 13 | {{reflist}} | 18 | {{reflist}} |