title: Pancreatic reg gene expression is inhibited during cellular differentiation.
abstract: OBJECTIVE
  Factors that control pancreatic regenerating (reg I) gene expression are unknown, but it is believed that its expression may correspond with cellular differentiation. The authors recently demonstrated that reg I is expressed in AR42J, a rat acinar cell line whose state of differentiation can be modulated by dexamethasone. They used this line to study reg I expression during cellular proliferation and differentiation.
  
  
  METHODS
  After treatment of cells with 10 nmol/L dexamethasone, proliferation was assayed by thymidine incorporation; differentiation by expression of elastase I mRNA. Reg I mRNA levels were measured using a rat reg I cDNA probe, and reg I protein levels assayed by enzyme-linked immunosorbent assay of cellular lysates with a polyclonal antibody. The effect of gastrin, cholecystokinin and glucagon on reg I expression was also studied.
  
  
  RESULTS
  When compared with controls, treatment with dexamethasone caused thymidine incorporation to decrease and elastase mRNA levels to increase. Reg I mRNA decreased from controls of 100 +/- 16% to 40 +/- 18% (p < 0.05), and reg I protein levels decreased as well. Gastrointestinal hormones had no significant effect on either elastase or reg I gene expression.
  
  
  CONCLUSIONS
  Expression of reg I inversely correlates with the level of cellular differentiation, can be modulated via the glucocorticoid receptor, and is a potential marker of gastrointestinal epithelial differentiation. Despite its presence within a pancreatic acinar cell line, reg I gene expression is not modulated by gastrointestinal hormones.
authors.affiliation: Department of Surgery, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Zenilman
authors.forename: T H
authors.initials: TH
authors.lastname: Magnuson
authors.forename: R
authors.initials: R
authors.lastname: Perfetti
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: A R
authors.initials: AR
authors.lastname: Shuldiner
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D005786:Gene Expression Regulation; D005809:Genes, Regulator / Q000235:genetics*; D010179:Pancreas / Q000166:cytology*; D051381:Rats