DECIDUAL TRANSFORMATION OF HUMAN EXTRAUTERINE MESENCHYMAL CELLS IS ASSOCIATED WITH THE APPEARANCE OF INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN-1

Human extrauterine decidual cells were studied for the presence of insulin-like growth factor-binding protein-1 (IGFBP-1) by using an avidin-biotin complex immunoperoxidase method with a purified monoclonal antibody 6303 against IGFBP-1. It is well established that human decidua expresses mRNA for IGFBP-1 and synthesizes and secretes this protein. We now describe, for the first time, that cells morphologically similar to uterine decidual cells found beneath the peritoneal mesothelium in inguinal hernia and in the cervical mucosa during normal pregnancy and in the mesenchymal tissue of the Fallopian tubes and ovaries at term react with the monoclonal antibody for IGFBP-1 equally to endometrial decidual cells. These results imply that the extrauterine mesenchymal cells, which have undergone decidual transformation, are not only morphologically but also functionally, similar to their counterparts in the uterus. Secondly, the data suggest that IGFBP-1 expression is associated with a special type(s) of cells and a certain stage of differentiation rather than special organs in the body.