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