New peptides, hormones and parturition

This brief review emphasizes the importance of three novel discovered facto rs produced by fetal membranes, placenta and/or by the fetus itself in regu lating uterine contractility. We have shown that, as reported for other hor mones 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, directl y or indirectly, myometrial contractility during pregnancy, although much r emains to be learned about the mechanisms controlling adrenomedullin expres sion by the feto-placental tissues cells during pregnancy. Continued research is necessary to better define the complex interactions t hat result in parturition, both at term and preterm, and to allow ii more r ational approach to management of the premature labor, exploring new possib le pharmacological solutions.