胰淀素对大鼠胰岛素分泌的影响及其机理的探讨

Effect of amylin on insulin secretion in rat pancreatic islets and its mechanism

目的 为研究胰淀素（ Ａｍｙｌｉｎ） 对大鼠胰岛细胞分泌胰岛素的影响和机理。方法 用放免和荧光方法分别检测经不同浓度胰淀素温育的大鼠胰岛细胞的胰岛素分泌量、细胞内 Ｃａ 《及ｃ Ａ Ｍ Ｐ 含量。结果 在胰淀素１０μｍｏｌ／ Ｌ 组中高糖刺激下的胰岛素含量、细胞内 Ｃａ 《含量，细胞内ｃ Ａ Ｍ Ｐ 含量分别为０ ．８９ ±０ ．２１ｎｇ／ ｍｌ、６３ ±１０ｎｍｏｌ／ Ｌ、２９ ．３ ±３ ．３ｐｍｏｌ／１ ×１０６ 细胞与对照组（１ ．７５ ±０ ．４２ｎｇ／ｍｌ、１３５ ±１０ｎ ｍｏｌ／ Ｌ、３６ ．３ ±７ ．４ｐｍｏｌ／ Ｌ） 比较，其中胰岛素分泌量、细胞内 Ｃａ 《含量均明显降低， Ｐ＜ ０ ．０１ ，细胞内ｃ Ａ Ｍ Ｐ 含量有减少趋势。结论 高浓度的胰淀素抑制了胰岛细胞内 Ｃａ 《升高和／ 或细胞内ｃ Ａ Ｍ Ｐ 形成，可能是胰岛素分泌减少的原因之一。

Objective To study the effect of Amylin on insulin secretion in rat pancreatic islet cells and its mechanism. Methods Radio immunological and fluorescence methods were used to determine the amount of insulin secretion as well as content of intracellular Ca and cAMP by the rat islet cells incubated with amylin in different concentrations. Results In the 10μM/L amylin group, the glucose stimulated insulin release volume, intracellular Ca and cAMP content were 0.89±0.21ng/ml, 63±10nmol/L and 29.3±3.3pmol/1×10 6 cell respectively as compared with the control group (1.75±0.41ng/ml, 135±10nmol/L and 36.3±7.4 pmol/1×10 6 cells respectively). The insulin release volume and intracellular Ca decreased remarkably (P<0.01), while cAMP content had a tendency to decrease. Conclusion High concentration of amylin is responsible for the prevention of rise of Ca inside the islet B cells and /or the decrease of cAMP content which is one of the causes that bring about the decreased release of insulin.