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


CONCLUSIONS
Inhibition of GDP on increase in [Ca2+]i reduces SA(I) stimulated enzymes secretion in pancreatic acini.
Yang
W X
WX
Deparment of Biophysics, Nankai University, Tianjin 300071, China. Yangwenx@public.tpt.tj.cn
Yu
Y
Y
Zhang
W Z
WZ
Wang
H
H
Li
X D
XD
Zhao
Y Y
YY
Liang
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D006153:Guanosine Diphosphate / Q000494:pharmacology*; D008297:Male; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D010179:Pancreas / Q000166:cytology / Q000201:enzymology*; D010194:Pancreatin / Q000378:metabolism; D051381:Rats; D012503:Saponins / Q000494:pharmacology*
D012503:Saponins; D006153:Guanosine Diphosphate; D009828:Oleanolic Acid; D010194:Pancreatin; D002118:Calcium; C025759:saikosaponin D