Immunohistochemical localization of epidermal growth factor, transforming growth factor-alpha and growth factor-beta s in the caprine peri-implantation period

Control over the action of steroid hormones in the uterus and conceptus during the initial period of gestation appears to be regulated locally by growth factors. This study involved immunohistochemical detection of epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha) and transforming growth factor-beta s (TGF-beta s), to determine their role in the caprine peri-implantation period. Epidermal growth factor was expressed in the luminal and glandular endometrial epithelium of goats on all days studied (Days 22 to 30 post coitum), but it was not detected in trophoblastic cells or in other embryonic structures. Between Days 22 and 30 post coitum, TGF-alpha was detected in the epithelial cells and superficial stroma of the uterus and in the trophoendodermic cells of the embryo. Transforming growth factor-beta s expression, observed in the endometrium, embryo and extraembryonic membranes on Day 22 post coitum, decreased by Day 24 post coitum and disappeared in the embryo by Day 30 post coitum, while remaining in the other structures. The presence of these growth factors during the peri-implantation period in the goat suggests their participation in proliferation and differentiation phenomena which occur during implantation and embryonic development.