Molecular mechanisms of gonadotropin-releasing hormone neuronal migration.

Gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment, migrate along olfactory nerves to the cribriform plate and then diverge caudally to the forebrain to reach their final destination in the hypothalamus. Here, GnRH neurons are dispersed in a network that synchronously releases GnRH in a pulsatile manner to activate pituitary gonadotropin production. Gonadotropins in turn promote gametogenesis and steroidogenesis from the gonad, ensuring reproductive competence. Failure of GnRH neurons to migrate normally results in deficient activation of the reproductive axis and delayed or absent pubertal maturation. The exact mechanisms that direct GnRH neuronal migration are under active investigation. This article will review new information concerning factors regulating GnRH neuronal migration and the intracellular signaling pathways involved in this process.