Curry D L, Reaven G, Reaven E
Am J Physiol. 1984 Sep;247(3 Pt 1):E385-8. doi: 10.1152/ajpendo.1984.247.3.E385.
Previous studies have shown that cells from older Sprague-Dawley rats secrete insulin less efficiently in response to a maximal glucose challenge than do beta-cells from young animals. In the current study we have asked whether this change in beta-cell response occurs in another strain of rat, and, if so, whether the secretory defect occurs at submaximal as well as maximal glucose stimulatory levels. Pancreas perfusions were carried out on 2- and 12-mo-old Fischer 344 rats at perfusate glucose concentrations of 150 and 300 mg/dl. The secretory data for each pancreas was subsequently corrected for differences in islet cell mass and expressed as insulin secretion per unit islet cell. The results show that 12-mo-old Fischer rats release more insulin per total pancreas than do 2-mo-old animals at both glucose concentrations. However when corrected for islet cell mass, the amount of insulin secretion per islet cell is actually reduced in the older Fischer rat. These data are comparable to those seen previously in the 12-mo-old Sprague-Dawley rat and indicate that the insulin secretory defect seen as rats grow older is not species specific.
先前的研究表明，与幼年动物的β细胞相比，老年斯普拉格-道利大鼠的细胞在最大葡萄糖刺激下分泌胰岛素的效率较低。在本研究中，我们探究了这种β细胞反应的变化是否也发生在另一品系的大鼠中，如果是，分泌缺陷是否在次最大和最大葡萄糖刺激水平下均会出现。对2月龄和12月龄的费希尔344大鼠进行胰腺灌注，灌注液葡萄糖浓度分别为150和300mg/dl。随后，对每个胰腺的分泌数据进行校正，以消除胰岛细胞数量的差异，并表示为每单位胰岛细胞的胰岛素分泌量。结果显示，在两种葡萄糖浓度下，12月龄的费希尔大鼠每个胰腺释放的胰岛素均多于2月龄的动物。然而，校正胰岛细胞数量后，老年费希尔大鼠每个胰岛细胞的胰岛素分泌量实际上减少了。这些数据与先前在12月龄斯普拉格-道利大鼠中观察到的数据相当，表明随着大鼠年龄增长出现的胰岛素分泌缺陷并非物种特异性的。
