title: Strain Differences Determine the Suitability of Animal Models for Noninvasive In Vivo Beta Cell Mass Determination with Radiolabeled Exendin.
abstract: Noninvasive beta cell mass (BCM) quantification is a crucial tool to understand diabetes development and progression. [(111)In]exendin is a promising agent for in vivo beta cell imaging, but tracer testing has been hampered by the lack of well-defined rodent models.
  
  
  
  Biodistribution and pancreatic uptake of [(111)In]exendin were compared in rats and mice. In selected models, the amount of [(111)In]exendin accumulation in the pancreas and other organs was determined using a model of alloxan-induced beta cell loss. GLP-1R expression levels were analyzed by RT-PCR and immunohistochemistry.
  
  
  
  Namely Brown Norway rats showed beta-cell-specific tracer accumulation and favorable pancreas-to-background ratios for noninvasive BCM determination. Mice displayed receptor-mediated [(111)In]exendin uptake in endocrine and exocrine pancreas, in spite of very low GLP-1R expression in exocrine tissue.
  
  
  
  Rats display better characteristics for in vivo BCM determination than mice and are suggested as a more adequate model for humans.
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO BOX 9101, 6500 HB, Nijmegen, The Netherlands. Stefanie.willekens@radboudumc.nl.
authors.forename: Stefanie M A
authors.initials: SM
authors.lastname: Willekens
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO BOX 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Lieke
authors.initials: L
authors.lastname: Joosten
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO BOX 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Otto C
authors.initials: OC
authors.lastname: Boerman
authors.affiliation: ULB Center for Diabetes Research, Université Libre de Bruxelles (ULB), Brussels, Belgium.
authors.forename: Alexander
authors.initials: A
authors.lastname: Balhuizen
authors.affiliation: ULB Center for Diabetes Research, Université Libre de Bruxelles (ULB), Brussels, Belgium.
authors.forename: Decio L
authors.initials: DL
authors.lastname: Eizirik
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO BOX 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Gotthardt
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO BOX 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Maarten
authors.initials: M
authors.lastname: Brom
mesh_terms: D000496:Alloxan; D000818:Animals; D000077270:Exenatide; D007150:Immunohistochemistry; D007205:Indium Radioisotopes; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000378:metabolism*; D008815:Mice, Inbred Strains; D023421:Models, Animal; D010455:Peptides / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000737:chemistry*; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D013045:Species Specificity; D014018:Tissue Distribution; D014688:Venoms / Q000737:chemistry*
chemical_list: D007205:Indium Radioisotopes; D010455:Peptides; D019275:Radiopharmaceuticals; D014688:Venoms; D000496:Alloxan; D000077270:Exenatide
keywords: Beta cell mass; Diabetes; Exendin; GLP-1R; Receptor targeting