Li Jiaxu, Kuang Yang, Mason Clinton C
Department of Mathematics and Statistics, Arizona State University, Tempe, AZ 85287-1804, USA.
J Theor Biol. 2006 Oct 7;242(3):722-35. doi: 10.1016/j.jtbi.2006.04.002. Epub 2006 May 18.
In the glucose-insulin regulatory system, ultradian insulin secretory oscillations are observed to have a period of 50-150 min. After pioneering work traced back to the 1960s, several mathematical models have been proposed during the last decade to model these ultradian oscillations as well as the metabolic system producing them. These currently existing models still lack some of the key physiological aspects of the glucose-insulin system. Applying the mass conservation law, we introduce two explicit time delays and propose a more robust alternative model for better understanding the glucose-insulin endocrine metabolic regulatory system and the ultradian insulin secretory oscillations for the cases of continuous enteral nutrition and constant glucose infusion. We compare the simulation profiles obtained from this two time delay model with those from the other existing models. As a result, we notice many unique features of this two delay model. Based on our intensive simulations, we suspect that one of the possibly many causes of ultradian insulin secretion oscillations is the time delay of the insulin secretion stimulated by the elevated glucose concentration.
在葡萄糖-胰岛素调节系统中，观察到超日胰岛素分泌振荡的周期为50 - 150分钟。自20世纪60年代的开创性工作以来，在过去十年中已经提出了几个数学模型，用于模拟这些超日振荡以及产生它们的代谢系统。这些现有的模型仍然缺乏葡萄糖-胰岛素系统的一些关键生理方面。应用质量守恒定律，我们引入了两个明确的时间延迟，并提出了一个更稳健的替代模型，以便更好地理解葡萄糖-胰岛素内分泌代谢调节系统以及连续肠内营养和恒定葡萄糖输注情况下的超日胰岛素分泌振荡。我们将从这个双时间延迟模型获得的模拟曲线与其他现有模型的模拟曲线进行比较。结果，我们注意到这个双延迟模型的许多独特特征。基于我们的密集模拟，我们怀疑超日胰岛素分泌振荡可能的众多原因之一是葡萄糖浓度升高刺激胰岛素分泌的时间延迟。
