Growth factor expression during rat development: a comparison of TGF-beta 3, TGF-alpha, bFGF, PDGF and PDGF-R

Int J Exp Pathol. 1993 Feb;74(1):87-96.


At least part of the mechanism underlying fetal development appears to be the production of a number of growth factors considered important in the process of tumour formation. Using immunocytochemistry, we have investigated the temporal and spatial pattern of expression of some of the important growth factors, by the fetus. We describe here the cellular localization of transforming growth factor beta 3 (TGF-beta 3), platelet derived growth factor (PDGF) and its receptor (PDGF-R), TGF-alpha and basic fibroblast growth factor (bFGF) in the fetal rat from day 13 to 21 of gestation. Using antisera raised against an N-terminal portion of TGF-beta 3, immunoreactivity peaked around day 16 and was seen predominantly within epithelial cells. However, using antisera raised against the C-terminal of this molecule immunoreactivity was seen exclusively within the extracellular matrix underlying adjacent epithelia, and was maintained up until day 21 of gestation. Strong expression of TGF-alpha was seen in cells of most organs throughout the gestation period studied. Immunoreactivity for bFGF, PDGF and PDGF-R peaked around day 18 in both epithelial and mesenchymal cells of all major organ systems and then declined by day 21. These data suggest distinct roles for each factor during embryogenesis and tumorigenesis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Embryonic and Fetal Development / physiology*
  • Epithelium / chemistry
  • Epithelium / embryology
  • Fetus / chemistry
  • Fibroblast Growth Factor 2 / metabolism*
  • Immunoenzyme Techniques
  • Platelet-Derived Growth Factor / metabolism*
  • Rats
  • Rats, Wistar
  • Receptors, Platelet-Derived Growth Factor / metabolism*
  • Transforming Growth Factor alpha / analysis
  • Transforming Growth Factor beta / analysis
  • Transforming Growth Factors / metabolism*


  • Platelet-Derived Growth Factor
  • Transforming Growth Factor alpha
  • Transforming Growth Factor beta
  • Fibroblast Growth Factor 2
  • Transforming Growth Factors
  • Receptors, Platelet-Derived Growth Factor