title: Changes in IP3 receptor are associated with altered calcium response to cholecystokinin in diabetic rat pancreatic acini.
abstract: OBJECTIVE
  Pancreatic acini of diabetic rats release amylase less than normal acini on cholecystokinin (CCK) stimulation. Pancreatic enzyme secretion by CCK is closely related to the second messenger inositol 1,4,5-trisphosphate (IP3), which mobilizes intracellular calcium stores via the endoplasmic reticulum-located receptor IP3 (IP3R). Recently, we observed altered intracellular calcium response on CCK-8 stimulation in streptozotocin (STZ)- treated diabetic rat acini.
  
  
  METHODS
  To determine whether IP3R is involved in altered calcium response, we measured inositol phosphate (IP) formation and the expression and phosphorylation of type III IP3R protein in diabetic acini. Also, CCK receptor mRNA expression was examined to determine whether the changes in IP formation and IP3R protein phosphorylation in diabetic acini might result from the defect at the postreceptor level.
  
  
  RESULTS
  CCK-8-induced IP formation at all concentrations used was significantly reduced in diabetic acini, though IP formation was increased in a concentration-dependent manner. The expression of type III IP3R protein was significantly reduced in diabetic acini. Additionally, CCK-8-stimulated phosphorylation of type III IP3R protein was not observed in diabetic acini. However, the reduction of CCK receptor mRNA expression was not detected in diabetic acini.
  
  
  CONCLUSIONS
  Our results indicate that altered calcium response to CCK-8 in diabetic acini might be associated with a post-CCK receptor defect including the changes in IP formation, type III IP3R protein expression, and phosphorylation of type III IP3R protein.
authors.affiliation: Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Gyeong Ryul
authors.initials: GR
authors.lastname: Ryu
authors.forename: Choon Ho
authors.initials: CH
authors.lastname: Sung
authors.forename: Myung-Jun
authors.initials: MJ
authors.lastname: Kim
authors.forename: Jong-Ho
authors.initials: JH
authors.lastname: Sung
authors.forename: Kweon-Haeng
authors.initials: KH
authors.lastname: Lee
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Park
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Sim
authors.forename: Do Sik
authors.initials: DS
authors.lastname: Min
authors.forename: Duck-Joo
authors.initials: DJ
authors.lastname: Rhie
authors.forename: Shin Hee
authors.initials: SH
authors.lastname: Yoon
authors.forename: Sang June
authors.initials: SJ
authors.lastname: Hahn
authors.forename: Myung-Suk
authors.initials: MS
authors.lastname: Kim
authors.forename: And Yang-Hyeok
authors.initials: AY
authors.lastname: Jo
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002766:Cholecystokinin / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011949:Receptors, Cholecystokinin / Q000096:biosynthesis; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D012844:Sincalide / Q000378:metabolism*; D013311:Streptozocin; D014316:Tritium / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007295:Inositol Phosphates; D012333:RNA, Messenger; D011949:Receptors, Cholecystokinin; D018160:Receptors, Cytoplasmic and Nuclear; D014316:Tritium; D013311:Streptozocin; D002766:Cholecystokinin; D012844:Sincalide; D002118:Calcium