Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
Academic Editor: William Okulicz
The steroid hormone progesterone (P) plays a pivotal role in the establishment and maintenance of pregnancy. The well-known function of P during early pregnancy is to regulate (i) uterine receptivity for blastocyst attachment, (ii) progressive phases of embryo-uterine interactions, and (iii) differentiation of the endometrial stroma that maintains an environment conducive for the growth and development of the implanting embryo. The cellular actions of P are mediated through intracellular progesterone receptors (PRs), which are well-studied gene regulators. It is postulated that hormone-occupied PRs trigger the expression of specific gene networks in different cell types within the uterus and the products of these genes mediate the hormonal effects during early pregnancy. In the present article, we provide a brief description of the molecules that have emerged as candidate markers of progesterone action in rodents and humans during implantation.