Korean J Gastroenterol.  2003 Dec;42(6):519-526.

Altered Cholecystokinin-induced Calcium Signal in Streptozotocin-induced Diabetic Rat Pancreatic Acini

Affiliations
  • 1Department of Physiology, The Catholic University of Korea College of Medicine, Seoul, Korea. mjunkim@catholic.ac.kr

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.

Keyword

Streptozotocin; Pancreatic acini; [Ca2+]i; Cholecystokinin; Amylase

MeSH Terms

Amylases/*secretion
Animals
Calcium Signaling/*drug effects
Diabetes Mellitus, Experimental/*physiopathology
Pancreas/cytology/metabolism/*secretion
Rats
Rats, Sprague-Dawley
Sincalide/*pharmacology
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