Role of steroid hormone-regulated genes in implantation

The endometrium acquires the ability to implant the developing embryo within a specific time window, termed the "receptive phase." During this period, the endometrium undergoes pronounced structural and functional changes induced by the ovarian steroids, estrogen and progesterone, which prepare it to be receptive to invasion by the embryo. These steroid-induced molecules, when identified, may serve as useful markers of uterine receptivity. In this article, we provide a brief description of one such molecule that has emerged as candidate marker of steroid hormone action in rats and humans during implantation.