[Altered cholecystokinin-induced calcium signal in streptozotocin-induced diabetic rat pancreatic acini].
OBJECTIVE
Pancreatic acini of streptozotocin (STZ)-induced diabetic rats release amylase less than normal acini on cholecystokinin (CCK) stimulation. Pancreatic enzyme secretion has been closely related to the intracellular calcium concentration ([Ca2(+)](i)) of the acinar cell. In the present study, sequential changes of the intracellular calcium signal which probably underlie the altered enzyme secretion in response to CCK-8 were investigated using pancreatic acini from diabetic rats.


METHODS
Diabetic rats were prepared by single intravenous injection of STZ (70 mg/kg). Stimulating experiments with CCK-8 were performed 7 days later. Pancreatic acini were isolated by collagenase digestion. Amylase release and [Ca2(+)](i) were measured by colorimethod and calcium imaging, respectively. The geometry of intracellular calcium signal was analyzed.


RESULTS
Normal acini exhibited concentration-dependent [Ca2(+)](i) increase and regular oscillatory calcium signal on CCK-8 stimulation. Amylase release was also concentration-dependent. However, diabetic acini showed significantly less [Ca2(+)](i) increase, prolonged time to peak [Ca2(+)](i), decreased calcium spikes number, and decreased amylase release compared with normal acini. The decreased [Ca2(+)](i) in diabetic acini was restored significantly by insulin treatment.


CONCLUSIONS
Relatively decreased amylase release in diabetic pancreatic acini in response to CCK, appears to be associated with altered calcium signal due to insulin deficiency.
Kim
Myung-Jun
MJ
Department of Physiology, The Catholic University of Korea College of Medicine, Socho-gu, Seoul, Korea.
Ryu
Gyeong-Ryul
GR
Sung
Jong-Ho
JH
Min
Do Sik
DS
Rhie
Duck-Joo
DJ
Yoon
Shin Hee
SH
Hahn
Sang June
SJ
Jo
Yang-Hyeok
YH
Kim
Myung-Suk
MS
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects*; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012844:Sincalide / Q000494:pharmacology*
D000681:Amylases; D012844:Sincalide