Reference
Caumo, A., & Luzi, L. (2004). First-phase insulin secretion: Does it exist in real life? Considerations on shape and function. American Journal of Physiology-Endocrinology and Metabolism, 287(3), E371–E385. https://doi.org/10.1152/ajpendo.00139.2003
Info
FirstAuthor:: Caumo, Andrea
Author:: Luzi, Livio
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Title:: First-phase insulin secretion: does it exist in real life? Considerations on shape and function
Year:: 2004
Citekey:: CaumoLuzi_2004_FirstphaseInsulinSecretion
itemType:: journalArticle
Journal:: American Journal of Physiology-Endocrinology and Metabolism
Volume:: 287
Issue:: 3
Pages:: E371-E385
DOI:: 10.1152/ajpendo.00139.2003
Link
Abstract
To fulfill its preeminent function of regulating glucose metabolism, insulin secretion must not only be quantitatively appropriate but also have qualitative, dynamic properties that optimize insulin action on target tissues. This review focuses on the importance of the first-phase insulin secretion to glucose metabolism and attempts to illustrate the relationships between the first-phase insulin response to an intravenous glucose challenge and the early insulin response following glucose ingestion. A clear-cut first phase occurs only when the β-cell is exposed to a rapidly changing glucose stimulus, like the one induced by a brisk intravenous glucose administration. In contrast, peripheral insulin concentration following glucose ingestion does not bear any clear sign of biphasic shape. Coupling data from the literature with the results of a β-cell model simulation, a close relationship between the first-phase insulin response to intravenous glucose and the early insulin response to glucose ingestion emerges. It appears that the same ability of the β-cell to produce a pronounced first phase in response to an intravenous glucose challenge can generate a rapidly increasing early phase in response to the blood glucose profile following glucose ingestion. This early insulin response to glucose is enhanced by the concomitant action of incretins and neural responses to nutrient ingestion. Thus, under physiological circumstances, the key feature of the early insulin response seems to be the ability to generate a rapidly increasing insulin profile. This notion is corroborated by recent experimental evidence that the early insulin response, when assessed at the portal level with a frequent sampling, displays a pulsatile nature. Thus, even though the classical first phase does not exist under physiological conditions, the oscillatory behavior identified at the portal level does serve the purpose of rapidly exposing the liver to elevated insulin levels that, also in virtue of their up-and-down pattern, are particularly effective in restraining hepatic glucose production.
Blue: Important conclusions
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under physiological circumstances, the key feature of the early insulin response seems to be the ability to generate a rapidly increasing insulin profile
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even though the classical first phase does not exist under physiological conditions, the oscillatory behavior identified at the portal level does serve the purpose of rapidly exposing the liver to elevated insulin levels that, also in virtue of their up-and-down pattern, are particularly effective in restraining hepatic glucose production
Yellow: Interesting
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A clear-cut first phase occurs only when the -cell is exposed to a rapidly changing glucose stimulus, like the one induced by a brisk intravenous glucose administration. In contrast, peripheral insulin concentration following glucose ingestion does not bear any clear sign of biphasic shape
Highlight ( Page )
the same ability of the -cell to produce a pronounced first phase in response to an intravenous glucose challenge can generate a rapidly increasing early phase in response to the blood glucose profile following glucose ingestion. This early insulin response to glucose is enhanced by the concomitant action of incretins and neural responses to nutrient ingestion