title: Pancreatic thread protein is mitogenic to pancreatic-derived cells in culture.
abstract: OBJECTIVE
  Pancreatic thread proteins (PTPs) are acinar cell products and members of the regenerating gene (reg) family. reg expression increases during islet regeneration, is depressed during aging-related islet dysfunction, and may be important in beta-cell growth and maintenance. The aim of this study was to examine the genetic expression of reg in pancreatic-derived cells in vitro and the mitogenic effect of PTP/reg protein on these cells.
  
  
  METHODS
  reg gene expression was measured by Northern analysis in three rat pancreatic cell lines: ARIP (ductal), AR42J (acinar), and RIN (beta-cell). PTP/reg protein was isolated from bovine and human pancreas. Cells were cultured with PTP/reg for 72 hours, and thymidine incorporation was measured.
  
  
  RESULTS
  reg messenger RNA was detected in AR42J but not in ARIP or RIN. PTP/reg protein was mitogenic to RIN and ARIP in a dose-related fashion but not to AR42J. It was not mitogenic to cultured mature rat islets.
  
  
  CONCLUSIONS
  reg messenger RNA is expressed in acinar but not in beta-cell or ductal pancreatic cell lines. PTP/reg protein was mitogenic to both beta-cell and ductal cell lines but not to mature, nondividing islets. This supports the hypothesis that PTP/reg protein is an acinar cell-derived mediator of beta-cell growth and may be involved in modulating the duct-to-islet axis.
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Zenilman
authors.forename: T H
authors.initials: TH
authors.lastname: Magnuson
authors.forename: K
authors.initials: K
authors.lastname: Swinson
authors.forename: J
authors.initials: J
authors.lastname: Egan
authors.forename: R
authors.initials: R
authors.lastname: Perfetti
authors.forename: A R
authors.initials: AR
authors.lastname: Shuldiner
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D015870:Gene Expression; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology; D051847:Lithostathine; D008297:Male; D008934:Mitogens / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D009419:Nerve Tissue Proteins; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D010183:Pancreatic Ducts / Q000166:cytology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats
chemical_list: D002135:Calcium-Binding Proteins; D051847:Lithostathine; D008934:Mitogens; D009419:Nerve Tissue Proteins; C497617:REG1A protein, human; D012333:RNA, Messenger; C497616:Reg1a protein, rat