Human Endometrial Transforming Growth Factor-α: A Transmembrane, Surface Epithelial Protein That Transiently Disappears During the Midsecretory Phase of the Menstrual Cycle:

Objectives:To characterize the forms of transforming growth factor-alpha (TGF-α) in normal human endometrium, to evaluate the regional and temporal changes in TGF-α expression, and to correlate the pattern of TGF-α expression with physiologic events in the endometrium.Methods:Immunohistochemistry and Western blot analyses were performed using two TGF-α antisera, one raised against the active extracellular N-terminus and the other recognizing the intracellular carboxy terminus of the protein. Immunohistochemistry was performed on hysteroctomy specimens from premenopausal women with normal menstrual cycles. Soluble and membrane-bound endometrial proteins were isolated from fresh tissue for Western blot analysis.Results:Antibodies recognizing the intracellular and extracellular domains of TGF-α exhibited identical immunohistochemical staining patterns. Transforming growth factor-α localized primarily to endometrial epithelial cells, and the most intense staining was in the luminal surface epithelium. In the ...