IMMUNOCYTOCHEMICAL LOCALIZATION OF TRANSFORMING-GROWTH-FACTOR-ALPHA, EPIDERMAL GROWTH-FACTOR AND EPIDERMAL GROWTH-FACTOR RECEPTOR IN THE CAT ENDOMETRIUM AND PLACENTA

This study was undertaken to determine the immunocytochemical localiza tion of transforming growth factor alpha, epidermal growth factor and epidermal growth factor receptor in the endometrium of ovariectomized cats treated with oestradiol-17 beta and/or progesterone and in the en dometrium and placenta of pregnant cats. Specific immunostaining was o bserved for all three antibodies. Moderate immunostaining for transfor ming growth factor alpha was observed in the epithelium of ovariectomi zed and oestrogen-treated cats. Dark epithelial staining was observed throughout pregnancy. The epithelial cells in progesterone-treated and peri-implantation animals contained dense deposits of reaction produc t, which were not reduced in intensity when immunoabsorbed antiserum w as used. For epidermal growth factor, light-moderate epithelial staini ng was observed in ovariectomized and steroid-treated animals, and thi s increased in pregnant cats. Stromal staining for both the transformi ng and the epidermal growth factors was limited in steroid-treated ani mals and increased as pregnancy continued. Dark staining for epidermal growth factor receptor was observed in the epithelium and stroma in a ll the animals studied. The tips of surface epithelial convolutions in the non-implantation sites were always more darkly stained than in ot her regions of the surface epithelium. Staining in the placental troph oblast was limited to the syncytiotrophoblast for the two growth facto rs and the cytotrophoblast for the receptor during most of pregnancy a nd was absent late in pregnancy. The placental maternal giant cells co ntained specific immunoreactivity for all the immunogens from the midd le of pregnancy to term. This study demonstrates that the two growth f actors and the epidermal growth factor receptor are present in the end ometrium and placenta of cats and suggests that these growth factors m ay play an autocrine/paracrine role during reproduction.