title: Endogenous somatostatin inhibits interaction of insulin and cholecystokinin on exocrine secretion of isolated, perfused rat pancreas.
abstract: BACKGROUND
  Although somatostatin inhibits pancreatic exocrine secretion, the inhibitory mechanism of endogenous somatostatin is not clearly understood.
  
  
  OBJECTIVE
  To investigate the effect of endogenous somatostatin on the interaction between endogenous insulin and exogenous cholecystokinin (CCK) in exocrine secretion of the totally isolated, perfused rat pancreas.
  
  
  METHODS
  Endogenous releases of somatostatin and insulin were induced by 18 mM glucose. Streptozotocin (75 mg/kg) or cysteamine (300 mg/kg) was injected into rats 24 hours before the experiment to deplete insulin or somatostatin in the pancreas.
  
  
  RESULTS
  Glucose (18 mM) enhanced CCK (10 pM)-stimulated secretions of fluid and amylase in the normal pancreas, which was further elevated by a somatostatin antagonist. Exogenous insulin (100 nM) also enhanced CCK-stimulated secretions in the streptozotocin-treated pancreas, which was also markedly increased by the somatostatin antagonist. The glucose (18 mM)-enhanced CCK-stimulated secretions were much higher in the cysteamine-treated pancreas than in the normal pancreas, which was dose-dependently reduced by exogenous somatostatin (30, 100 pM). However, endogenous or exogenous somatostatin did not modify the pancreatic responses to CCK alone.
  
  
  CONCLUSIONS
  Endogenous somatostatin inhibits the interaction of endogenous insulin and CCK on pancreatic exocrine secretion in the rat rather than reducing the action of CCK alone or endogenous release of insulin.
authors.affiliation: Department of Physiology, College of Medicine, Konyang University, Nonsan, Chungnam-Do, Korea.
authors.forename: Hyung Seo
authors.initials: HS
authors.lastname: Park
authors.forename: Hyo Seop
authors.initials: HS
authors.lastname: Yoon
authors.forename: Yong Deuk
authors.initials: YD
authors.lastname: Park
authors.forename: Zheng Yun
authors.initials: ZY
authors.lastname: Cui
authors.forename: Yun Lyul
authors.initials: YL
authors.lastname: Lee
authors.forename: Hyoung Jin
authors.initials: HJ
authors.lastname: Park
mesh_terms: D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D004347:Drug Interactions; D005947:Glucose / Q000494:pharmacology; D006727:Hormone Antagonists / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D006727:Hormone Antagonists; D007004:Hypoglycemic Agents; D007328:Insulin; D013004:Somatostatin; C043820:cyclo(7-aminoheptanoylphenylalanyl-tryptophyl-lysyl-benzylthreonyl); D002766:Cholecystokinin; D005947:Glucose