外源性胰高血糖素对大鼠胰岛B细胞形态和功能的影响

探讨溃疡自愈过程中胰高血糖素对胰岛B细胞调节作用改变的可能机理，同时从形态学方面为IAPP和胰岛素相伴释放及其调节提供依据。给大鼠皮下注射胰岛高血糖素后，取胰腺用免疫组织化学、原位杂交和图像分析方法观察Ins-和I－APP-IR细胞及proIns mRNA表达的变化。结果显示；给予外源性胰高血糖素后，与对照组比较，Ins-IR细胞的场面积明显减少，而IAPP－IR细胞的场面积减少不明显，胰岛B细胞内proIns mRNA杂交信号的平均光密度明显减低。以上结果提示：（1）外源性胰高血糖素促进胰岛素和IAPP相伴释放；但促胰岛素释放作用更明显。（2）外源性胰高血糖素抑制proIns mRNA的表达。

EFFECTS OF EXOGENOUS GLUCAGON ON MORPHOLOGY AND FUNCTION OF ISLET B CELLS OF RATS

The study was designed to explore the mechanism by which Glu changed the regulation on islet B cells during the healing process of gastric ulcer, morphologically to provide evidence for the cosecretion of IAPP and insulin and their regulation. The rats were given Glu by subcutaneous injection and the pancreata were excised for observing the changes of expression of Ins and IAPP IR cells and proinsulin mRNA by immunohistochemical staining and in situ hybridization. The samples were processed by image analysis. The results showed that after giving Glu, the area of Ins IR cells obviously decreased, however, the decreasing of IAPP IR cell area was not significant as compared with control group. The MOD of hybridization signal of proinsulin mRNA declined markedly. The present study suggests:(1) exogenous Glu promotes the cosecretion of insulin and IAPP, but the action of insulin promoting secretion is more obvous; (2)exogenous Glu inhibits the expression of proinsulin mRNA.