New peptides, hormones and parturition

This brief review emphasizes the importance of three novel discovered factors produced by fetal membranes, placenta and/or by the fetus itself in regulating uterine contractility. We have shown that, as reported for other hormones and substances, nitric oxide and endothelin may influence myometrial activity in an autocrine/paracrine manner interacting with other well-known agents such as prostaglandins, oxytocin and hormones. We also demonstrated that different isoforms of nitric oxide synthase (NOS) may play different roles throughout gestation and during labor. We have suggested that another peptide produced by trophoblast cells, adrenomedullin, may affect, directly or indirectly, myometrial contractility during pregnancy, although much remains to be learned about the mechanisms controlling adrenomedullin expression by the feto-placental tissues cells during pregnancy. Continued research is necessary to better define the complex interactions that result in parturition, both at term and preterm, and to allow a more rational approach to management of the premature labor, exploring new possible pharmacological solutions.