Department of Clinical Sciences Lund, Lund University, 22185 Lund, Sweden.
Biomolecules. 2022 Jul 12;12(7):976. doi: 10.3390/biom12070976.
This study explored the relationship between the glucose dose and insulin response from beta cells in vivo and in vitro in mice. Glucose was administered intravenously at different dose levels (from 0 to 0.75 g/kg) in anesthetized C57BL/6J mice, and the glucose and insulin concentrations were determined in samples taken after 50 min. Furthermore, freshly isolated mouse islets were incubated for 60 min in the presence of different concentrations of glucose (from 2.8 to 22.2 mmol/L) and insulin levels were analyzed in the medium. It was found that insulin levels increased after an intravenous injection of glucose with the maximal increase seen after 0.35 g/kg with no further increase after 0.5 or 0.75 g/kg. The acute increase in insulin levels (during the first 5 min) and the maximum glucose level (achieved after 1 min) showed a curvilinear relation with the half-maximal increase in insulin levels achieved at 11.4 mmol/L glucose and the maximal increase in insulin levels at 22.0 mmol/L glucose. In vitro, there was also a curvilinear relation between glucose concentrations and insulin secretion. Half maximal increase in insulin concentrations was achieved at 12.5 mmol/L glucose and the maximal increase in insulin concentrations was achieved at 21.5 mmol/L. Based on these data, we concluded that the glucose-insulin relation was curvilinear both in vivo and in vitro in mice with similar characteristics in relation to which glucose levels that achieve half-maximal and maximal increases in insulin secretion. Besides the new knowledge of knowing these relations, the results have consequences on how to design studies on insulin secretion to obtain the most information.
这项研究旨在探索体内和体外小鼠β细胞的葡萄糖剂量与胰岛素反应之间的关系。在麻醉的 C57BL/6J 小鼠中静脉内给予不同剂量水平的葡萄糖（0 至 0.75 g/kg），并在 50 分钟后取样本测定葡萄糖和胰岛素浓度。此外，将新鲜分离的胰岛在不同浓度的葡萄糖（2.8 至 22.2 mmol/L）存在下孵育 60 分钟，并分析培养基中的胰岛素水平。结果发现，静脉注射葡萄糖后胰岛素水平升高，在 0.35 g/kg 时达到最大增加，在 0.5 或 0.75 g/kg 时不再增加。胰岛素水平的急性增加（在最初的 5 分钟内）和最大葡萄糖水平（在 1 分钟后达到）与胰岛素水平的半最大增加呈曲线关系，半最大增加发生在 11.4 mmol/L 葡萄糖时，胰岛素水平的最大增加发生在 22.0 mmol/L 葡萄糖时。在体外，葡萄糖浓度与胰岛素分泌之间也存在曲线关系。胰岛素浓度的半最大增加发生在 12.5 mmol/L 葡萄糖时，胰岛素浓度的最大增加发生在 21.5 mmol/L 葡萄糖时。基于这些数据，我们得出结论，在体内和体外，小鼠的葡萄糖-胰岛素关系呈曲线关系，与体内达到胰岛素分泌半最大和最大增加的葡萄糖水平具有相似的特征。除了了解这些关系的新知识外，这些结果还对如何设计胰岛素分泌研究以获得最多信息产生了影响。
