PARACRINE REGULATION OF MENSTRUATION

Endometrial proliferation, secretion, vascular neoformation and modifi cation to shedding is under direct and/or indirect control of steroid hormones. The progressive modification of the endometrial architecture is due to its growth and differentiation. The new tissue regenerates monthly from a 2-5 mm to a 12-18 mm of complex tissue until it sheds u nder a co-ordinated network of bioactive molecules produced and activa ted during the menstrual cycle. The steroid hormones, the HLA-DR and i ntegrin molecules, the intense production of several proteins, the vas cular damage, and the disconnection of cell-cell and cell-matrix inter action are participating in both the endometrial preparation for embry onic implantation and the shedding and bleeding of the tissue itself. Menstruation is a process associated with damage to the epithelium, en dothelium and extracellular matrix, ending on controlled bleeding, tis sue dissolution and repair. Endometrial proteinases and tissue factor (TF) contribute to systemic factors to control the mechanisms of regul ation of tissue dissolution, tissue shedding, and vascular bleeding du ring menstruation. (C) 1998 Published by Elsevier Science Ireland Ltd. All rights reserved.