title: Biologically active human islet amyloid polypeptide/amylin in transgenic mice.
abstract: OBJECTIVE
  Human islet amyloid polypeptide (hIAPP), also named amylin, is a pancreatic beta cell protein implicated in the pathogenesis of pancreatic islet amyloid formation and type 2 diabetes mellitus. To study the (patho)physiological roles of hIAPP, we have generated transgenic mice that overexpress hIAPP mRNA, in relation to endogenous mouse IAPP (mIAPP) mRNA, in pancreatic beta cells. The biological activity of human and mouse IAPP derived from pancreatic extracts was determined.
  
  
  METHODS
  Pancreatic and plasma extracts of transgenic and control mice were analyzed by reversed-phase high-performance liquid chromatography (HPLC) and radioimmunoassay, yielding a separation of hIAPP from mIAPP. Biological activity of immunoreactive human and mouse IAPP components derived from pancreatic extracts was assessed by calcitonin receptor-mediated stimulation of cyclic AMP accumulation in T47D human breast carcinoma cells.
  
  
  RESULTS
  The predominant immunoreactive human and mouse IAPP gene products had the retention times on HPLC analysis of the corresponding synthetic peptides. The ratio of bioactive over immunoreactive hIAPP and mIAPP was 0.93 +/- 0.18 and 1.19 +/- 0.56 respectively. In extracts of two plasma pools from 4 transgenic animals, hIAPP was 4.6- to 7-fold more abundant than mIAPP.
  
  
  CONCLUSIONS
  This study has shown that correctly processed hIAPP produced in transgenic mouse pancreatic beta cells exhibits full biological activity. The results validate these transgenic mice for the study of (patho)physiological roles of hIAPP in vivo.
authors.affiliation: Department of Internal Medicine, Utrecht University, The Netherlands.
authors.forename: K L
authors.initials: KL
authors.lastname: van Hulst
authors.forename: W
authors.initials: W
authors.lastname: Born
authors.forename: R
authors.initials: R
authors.lastname: Muff
authors.forename: C
authors.initials: C
authors.lastname: Oosterwijk
authors.forename: M A
authors.initials: MA
authors.lastname: Blankenstein
authors.forename: C J
authors.initials: CJ
authors.lastname: Lips
authors.forename: J A
authors.initials: JA
authors.lastname: Fischer
authors.forename: J W
authors.initials: JW
authors.lastname: Höppener
mesh_terms: D000682:Amyloid / Q000235:genetics* / Q000502:physiology*; D000818:Animals; D001681:Biological Assay; D015152:Blotting, Northern; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D058228:Islet Amyloid Polypeptide; D051379:Mice; D008822:Mice, Transgenic; D010179:Pancreas / Q000737:chemistry*; D010949:Plasma / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011863:Radioimmunoassay; D014407:Tumor Cells, Cultured
chemical_list: D000682:Amyloid; D058228:Islet Amyloid Polypeptide; D012333:RNA, Messenger