title: Differential expression of EGF receptor in the pig duodenum during the transition phase from maternal milk to solid food.
abstract: BACKGROUND
  The aim of this investigation was to study the cell type-specific expression of epidermal growth factor receptor (EGF-R) and to evaluate changes of the EGF-R distribution during transition from maternal milk to solid food in the gastrointestinal tract of young piglets.
  
  
  METHODS
  Duodenal tissue probes from six pigs were taken 2 days before (-2d) and 2 days (+2d) and 14 days (+14d) after transition from milk to solid food. The specimens were fixed in methanol/glacial acetic acid (2 : 1). A monoclonal antibody against EGF-R was used to examine the pattern and topographical shift of EGF-R. To assess a possible correlation between EGR-R-positive cells and mitotic activity, the mitotic index (MI) were evaluated based on expression of the Ki-67 antigen.
  
  
  RESULTS
  A significant change in the topographical and cellular distribution of the EGF-R could be successfully determined during the transition period. The highest immunoreactivity for EGF-R was found in enterocytes 2 days before transition from maternal milk, predominantly around the villous tips. Two days after transition consistent staining along the villi and crypts could be demonstrated. Fourteen days later the expression was significant lower around the villous tips and was more concentrated in Brunner's glands. Additionally, distinct expression of the receptor is selectively found in stimulated goblet cells. The analysis of the mitotic activity during the transition period shows that cells that highly express the EGF-R have a rather low proliferation rate.
  
  
  CONCLUSIONS
  Our findings suggest that EGF plays an important role in cell differentiation (rather than cell proliferation) in young animals, and it may be involved in stimulating mucus secretion.
authors.affiliation: Institute of Anatomy and Physiology, University of Hohenheim, Fruwirthstrasse 35, 70593 Stuttgart, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schweiger
authors.forename: Martin
authors.initials: M
authors.lastname: Steffl
authors.forename: Werner M
authors.initials: WM
authors.lastname: Amselgruber
mesh_terms: D000821:Animal Feed; D000818:Animals; D000833:Animals, Suckling; D002011:Brunner Glands / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D004386:Duodenum / Q000166:cytology / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000502:physiology; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D008940:Mitotic Index; D013552:Swine; D014886:Weaning
chemical_list: D004815:Epidermal Growth Factor; D066246:ErbB Receptors