GDP对柴胡皂甙（I）促大鼠胰腺腺泡酶分泌和升高[Ca^2＋]i的影响

目的：研究鸟苷二磷酸（GDP）对柴胡皂甙（I）SA(I)]刺激大鼠胰腺腺泡酶分泌和胞内钙离子升高的影响。方法：分离大鼠胰腺腺泡细胞，用链球菌溶血素－O（SLO）通透细胞膜，检测腺泡分泌蛋白量标志腺泡酶分泌功能。用钙离子荧光指示剂Fluo-3和荧光光谱测定胞内钙离子浓度。结果：GDP可凶制SA（I）促胰腺腺泡的酶分泌作用，抑制作用随剂量增加而加强；SA（I）10μmol/L以双峰值为特征使Ca^2 ]i显著上升；GDP 5mmol/L,导致Ca^2 ]i逐步升高且两个峰值消失。细胞通透以后，与正常细胞相比，SA（I）刺激的30min酶分泌的累积量下降了57％；GDP5mmol/L使SA（I）刺激的早期酶分泌速率进一步降低。结论：GDP通过抑制细胞Ca^2 ]i的升高抑制了SA（I）刺激的胰腺腺泡酶分泌作用。

Inhibitory role of GDP on saikosaponin (I) stimulated enzymes secretion and rising of [Ca2+]i in rat pancreatic acini.

AIM: To study the role of guanosine diphosphate (GDP) on enzyme secretion and rising of Ca2+]i in saikosaponin (I) SA(I)] stimulated rat pancreatic acini. METHODS: Cell membrane of isolated rat pancreatic acini were permeabilized using streptolysin O (SLO). Enzymes secretions were indicated by detecting total protein secretions. Intracellular Ca2+ (Ca2+]i) was measured using Fluo-3 in SPEX spectrofluorimeter. RESULTS: The inhibition of GDP on SA(I) stimulated enzymes secretion increased with increasing GDP concentration. There were two peaks in the time course of increase in Ca2+]i evoked by SA(I) 10 micromol/L. After adding GDP 5 mmol/L, Ca2+]i rose gradually without the two peaks. In permeabilized acini, the accumulation of enzymes stimulated by SA(I) in 30 min reduced by 57 % compared with intact acini. GDP 5 mmol/L decreased the initial rate of secretion. CONCLUSION: Inhibition of GDP on increase in Ca2+]i reduces SA(I) stimulated enzymes secretion in pancreatic acini.