title: Oxytocin-stimulated insulin release in a clonal beta-cell line RINm5F: involvement of phospholipase C-dependent and -independent pathways.
abstract: OBJECTIVE
  To study the mechanisms underlying oxytocin (Oxy)-induced insulin release.
  
  
  METHODS
  In a clonal pancreatic beta-cell line, RINm5F cells.
  
  
  RESULTS
  Oxy increased insulin release and [Ca2+]i in a concentration-dependent manner. Oxy-induced insulin release was not altered by pretreatment with pertussis toxin (PT). U-73122 (2-8 mumol.L-1), a phospholipase C (PLC) inhibitor, concentration-dependently inhibited Oxy-induced increases in [Ca2+]i with IC50 value of 2.8 +/- 0.2 mumol.L-1. In addition, U-73122 diminished the Oxy-induced increase in intracellular concentration of inositol 1, 4, 5-triphosphate (IP3). U-73122 at 8 mumol.L-1 totally abolished the Oxy-induced increases in [Ca2+]i and IP3; however it reduced the Oxy-induced increase in insulin release only by 36% and 63% in the monolayer and suspended cell preparations, respectively.
  
  
  CONCLUSIONS
  Oxy increases insulin release through both PLC and non-PLC mediated signal transduction mechanisms.
authors.affiliation: Department of Veterinary Physiology and Pharmacology, Iowa State University, Ames 50011, USA.
authors.forename: B
authors.initials: B
authors.lastname: Lee
authors.forename: T H
authors.initials: TH
authors.lastname: Chen
authors.forename: W H
authors.initials: WH
authors.lastname: Hsu
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism* / Q000473:pathology; D010121:Oxytocin / Q000494:pharmacology*; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000502:physiology
chemical_list: D004963:Estrenes; D007295:Inositol Phosphates; D007328:Insulin; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D010121:Oxytocin; C058097:inositol 1,3,4-trisphosphate; D010738:Type C Phospholipases; D002118:Calcium