| Abstract: | Postnatal mammary gland development is highlydependent on the ovarian steroids, estrogen andprogesterone. However, evidence from both in vitro andin vivo studies indicates that steroid-induceddevelopment occurs indirectly, requiring stromalcooperation in epithelial proliferation andmorphogenesis. Stromal cells appear to influenceepithelial cell behavior by secretion of growth factorsand/or by altering the composition of the extracellular matrix inwhich epithelial cells reside. This review will discussthe requirement for stromal tissue in modulatingproliferative responses to ovarian hormones during postnatal development and the potential role ofthe EGF, IGF, HGF and FGF3 growth factorfamilies. Additionally, the roles of extracellularmatrix proteins, including fibronectin, collagens andlaminin, will be summarized. |
