title: Relative expression and localization of the insulin-like growth factor system components in the fetal, child and adult intestine.
abstract: BACKGROUND
  The insulin-like growth factors (IGFs) are important in the development and maintenance of the gastrointestinal tract.
  
  
  OBJECTIVE
  To compare the expression of IGFs and their receptors in the stomach and duodenum of the fetus, the child and the adult. To identify the cells mainly responsible for the production of the members of the IGF system.
  
  
  METHODS
  Tissue was obtained from fetus after abortion and from children and adults during diagnostic endoscopy and biopsy. The expression of the IGFs and their receptors was estimated by an RNAse protection assay and sections were stained with antisera to the components of IGF system.
  
  
  RESULTS
  The tissues from the stomach and the duodenum expressed the two IGFs and their receptors at all stages of life. The fetal IGF receptors I and II, were approximately ten times higher than in the child and IGF-II was five times higher. Immunohistochemical staining showed the components of the IGF system to be localized to the gastric glands and to the basotlateral border of the gastric epithelial cells. In the duodenum, they were concentrated at the apical portion of the epithelial tissue. They could also be identified in ganglion cells and nerves.
  
  
  CONCLUSIONS
  The IGFs and their receptors in the stomach and duodenum are expressed in all age groups and mostly are highest in the fetus. The IGF system proteins were located in the gastric glands and epithelium and in the apical portion of the villous epithelium of the duodenum.
authors.affiliation: Pediatric Gastroenterology Unit, Shaare Zedek Medical Centre, Jerusalem, 91031 Israel. zerem@zahav.net.il
authors.forename: Serem
authors.initials: S
authors.lastname: Freier
authors.forename: Maya
authors.initials: M
authors.lastname: Eran
authors.forename: Constantin
authors.initials: C
authors.lastname: Reinus
authors.forename: Ilana
authors.initials: I
authors.lastname: Ariel
authors.forename: Joseph
authors.initials: J
authors.lastname: Faber
authors.forename: Michael
authors.initials: M
authors.lastname: Wilschanski
authors.forename: Danny
authors.initials: D
authors.lastname: Braverman
mesh_terms: D037881:Aborted Fetus / Q000378:metabolism*; D000328:Adult; D001706:Biopsy; D002675:Child, Preschool; D005753:Gastric Mucosa / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D017451:Receptors, Somatomedin / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D013002:Somatomedins / Q000378:metabolism*; D013270:Stomach / Q000473:pathology
chemical_list: D012333:RNA, Messenger; D017451:Receptors, Somatomedin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D012260:Ribonucleases