Glycodelin: a pane in the implantation window.

Glycodelin is an endometrial protein with proposed immunomodulatory activity during human embryonic nidation. In this review we describe the effects of ovarian hormones on glycodelin transcription, synthesis, and secretion by human epithelial cells and focus on the importance of glycodelin in implantation. We demonstrate that glycodelin transcription, synthesis, and secretion by human epithelial cells are stimulated by progestins and antiprogestins but not by estrogen. Sequences localized within a 403-base-pair region flanking the 5' human glycodelin gene promoter appear to be responsible for transcriptional activation of this gene mediated by progesterone receptor-ligand complexes. Relaxin, purported to enhance glycodelin production in vivo and in prior in vitro studies, had no stimulatory effect on the expression of this gene in vitro in our models.