可乐定置换物对正常小鼠离体胰岛功能的影响

Effects of clonidine-displacing substance on the function of isolated islets from normal mice

目的 探讨可乐定置换物 (CDS)对胰岛功能的影响。方法 胶原酶和DNA酶联合消化法分离NMRI小鼠胰岛 ,RPMI1 640组织培养液过夜培养 ,采用MilliporeMultiscreen系统观察CDS对胰岛功能的影响。放免法测定孵育液中胰岛素及胰高糖素的浓度。结果 (1 )离体胰岛胰高糖素的分泌明显受葡萄糖浓度的抑制 ,CDS显著抑制胰高糖素的分泌 ,且抑制强度明显依赖于CDS的浓度。 (2 )离体胰岛胰岛素的分泌依赖于孵育液中的葡萄糖浓度 ,CDS明显刺激胰岛素的释放。Ca2 + 通道阻滞剂硝苯吡啶 (2 5μmol·L- 1 )及K+ 通道开放剂二氮嗪(1 0 0 μmol·L- 1 )可显著抑制胰岛素释放 ,但其作用可被CDS废除。结论 作为咪唑啉受体的内源性配体 ,CDS可刺激离体胰岛胰岛素的释放 。

Objective To research the effects of the clonidine-displacing substance (CDS) on the function of the islets. Methods The islets of NMRI mice were isolated by digestion combined with collagenase and DNase, incubated in RPMI 1640 tissue culture medium overnight. The experiments were completed with Millipore Multiscreen Assay System. The level of insulin and glucagon were measured by RIA. Results (1) Glucagon secretion of the isolated islets in incubation medium was inhibited by glucose. CDS could also inhibit glucagon secretion of the islets significantly, and the inhibitory effects was concentration-dependent. (2) Insulin secretion of the isolated islets in incubation medium was glucose concentration-dependent positively.The CDS could stimulate insulin secretion of the islets significantly. Nifedipine (Ca 2+ channel blocker) and diazoxide (K + channel opener) could inhibit the insulin release, but their effects could be abolished by CDS.Conclusion As an endogenous ligand of imidazoline receptors, CDS could stimulate insulin secretion, and inhibit glucagon release in the isolated islets.