Abstract
Progesterone, a critical hormone in reproduction, is a key sex steroid in the establishment and maintenance of early pregnancy and serves as an intermediary for synthesis of other steroid hormones. Progesterone production from the corpus luteum is a tightly regulated process which is stimulated and maintained by multiple factors, both systemic and local. Multiple regulatory systems, including classic mediators of gonadotropin stimulation such as the cAMP/PKA pathway and TGFβ-mediated signaling pathways, as well as local production of hormonal factors, exist to promote granulosa cell function and physiological fine-tuning of progesterone levels. In this manuscript, we provide an updated narrative review of the known mediators of human luteal progesterone and highlight new observations regarding this important process, focusing on studies published within the last five years. We will also review recent evidence suggesting that this complex system of progesterone production is sensitive to disruption by exogenous environmental chemicals that can mimic or interfere with the activities of endogenous hormones.