A novel approach for monitoring the endometrial cycle and detecting ovulation.

We report the presence of a cycle-dependent sialoglycoprotein in the endometrium. A monoclonal antibody (D9B1) to this glycoprotein has been derived and used to study tissue from 24 women with normal menstrual cycles. Results obtained with peroxidase immunohistochemistry suggest a highly significant variation in concentration of the glycoprotein, which is absent in the proliferative phase and present at maximal levels in the early secretory phase. The amount of antigen then diminishes slowly through the latter part of the secretory phase. The glycoprotein is produced in epithelial cells of glands and uterine lumen before being secreted across the apical cell surface. The secretory response is uniform in different areas of the tissue and within individual glands. However, considerable differences in secretory activity can be observed between adjacent glands in any part of the endometrium. Binding of the antibody is shown to be a new and novel parameter in characterization and standardization of the normal function of endometrium in response to ovarian hormones.