Human endometrial receptivity: gene regulation.

Endometrial receptivity is a self-limited period in which the endometrial epithelium (EE) acquires a functional and transient ovarian steroid-dependent status that allows blastocyst adhesion. Termed as "the window of implantation", this specific period opens 4-5 days after progesterone production or administration and closes after 9-10 days. Scientific knowledge on the endometrial receptivity process is fundamental for the understanding of human reproduction, but so far none of the proposed biochemical markers for endometrial receptivity has been proven to be clinically useful. In this work, we present strategies of cDNA analysis technologies that aim to clarify the fragmented information in this field. Specifically, the objective is the differential identification, cloning and sequencing of genes linked to endometrial receptivity in humans, combining differential display PCR and cDNA microarray analysis of endometrial epithelial-derived cell lines and endometrial samples obtained in the same patient 2 and 7 days after the luteinizing hormone (LH) surge (day LH+2) and (day LH+7), respectively.