Altered Cholecystokinin-induced Calcium Signal in Streptozotocin-induced Diabetic Rat Pancreatic Acini.
- Author:
Myung Jun KIM
1
;
Gyeong Ryul RYU
;
Jong Ho SUNG
;
Do Sik MIN
;
Duck Joo RHIE
;
Shin Hee YOON
;
Sang June HAHN
;
Yang Hyeok JO
;
Myung Suk KIM
Author Information
1. Department of Physiology, The Catholic University of Korea College of Medicine, Seoul, Korea. mjunkim@catholic.ac.kr
- Publication Type:Original Article ; English Abstract
- Keywords:
Streptozotocin;
Pancreatic acini;
[Ca2+]i;
Cholecystokinin;
Amylase
- MeSH:
Amylases/*secretion;
Animals;
Calcium Signaling/*drug effects;
Diabetes Mellitus, Experimental/*physiopathology;
Pancreas/cytology/metabolism/*secretion;
Rats;
Rats, Sprague-Dawley;
Sincalide/*pharmacology
- From:The Korean Journal of Gastroenterology
2003;42(6):519-526
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND/AIMS: 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.
