Progesterone inhibitory role on gastrointestinal motility.

Progesterone is a steroidal hormone that is produced from the corpus luteum of the ovaries and from the placenta. The main function of progesterone is to promote the secretory differentiation in the endometrium of the uterus and to maintain pregnancy by inhibiting uterine contractions throughout pregnancy. Progesterone performs its actions by activating the classical progesterone nuclear receptors that affect gene transcription and by the non-classical activation of cell surface membrane receptors that accounts for the rapid actions of progesterone. Besides the reproductive roles of progesterone, it exerts functions in many tissues and systems such as the nervous system, the bone, the vascular system, and the gastrointestinal (GI) tract. This review will summarize the recent literature that investigated the role of progesterone in GI tract motility. Most literature indicates that progesterone exerts an inhibitory role on gut smooth muscle cells in part by elevating nitric oxide synthesis which induces relaxation in smooth muscle. Moreover, progesterone inhibits the signaling pathways that lead to contraction such as Rho kinase inhibition. These data serve as a quick resource for the future directions of progesterone research that could lead to better understanding and more effective treatment of gender-related GI tract motility disorders.