Localization and characterization of EGF/TGF-alpha receptors on peri-implantation trophoblast in sheep.
Receptors for epidermal growth factor (EGF) have been identified on the ovine trophoblast as early as day 15 of gestation. A radioligand assay with 125I-labelled EGF was used to detect high and low affinity binding sites on the trophoblastic and placental membranes. The binding of 125I-labelled EGF was inhibited by increasing concentrations of unlabelled EGF. Competition studies with other peptide hormones including transforming growth factor alpha (TGF-alpha), insulin-like growth factor-I (IGF-I) and ovine placental lactogen confirmed the specificity of EGF/TGF-alpha for its receptor. Cross-linking experiments using disuccinimidyl suberate (DSS) revealed a radiolabelled band of relative molecular mass 170 kDa. Immunohistochemical localization of the receptors demonstrated their distribution on the epithelial layer cells. The presence of receptors for EGF/TGF-alpha suggests that these factors could be involved in the regulation of embryonic development and fetal growth.
Gharib-Hamrouche
N
N
Institut National de la Recherche Agronomique, Unité d'Endocrinologie de l'Embryon, Jouy-en-Josas, France.
Chêne
N
N
Guillomot
M
M
Martal
J
J
D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D010064:Embryo Implantation / Q000502:physiology*; D004848:Epithelium / Q000737:chemistry; D066246:ErbB Receptors / Q000032:analysis*; D005260:Female; D007150:Immunohistochemistry; D010920:Placenta / Q000737:chemistry; D011247:Pregnancy; D011869:Radioligand Assay; D012756:Sheep / Q000378:metabolism*; D014327:Trophoblasts / Q000737:chemistry*
D066246:ErbB Receptors