 In this study, researchers investigated the role of GDF-11 in the regulation of chronic gonadotropin, CGB, expression, and HCG production in the human placenta. They found that GDF-11 downregulates CGB expression and HCG production in two human choreocarsinoma cell lines, BWO, and JEG-3, as well as in primary cytotrophoblast, CTB, cells. Further investigation revealed that both ALK-4 and ALK-5 are necessary for the GDF-11 induced downregulation of CGB expression. Additionally, they discovered that GDF-11 activates SMAD-2-3 signaling pathways, which are responsible for the downregulation of CGB expression. Furthermore, they showed that the GDF-11 suppressed HCG production requires the ALK-4-5 mediated activation of SMAD-2-3 signaling pathways. These findings suggest that GDF-11 plays an important role in the regulation of CGB expression and HCG production in the human placenta. This article was authored by Ziyi Wu, Lingling Zhong, Yuan Yuanjiao, and others. We are article.tv, links in the description below.