Endocrine Abstracts

Human reproduction is regulated by a small number of hypothalamic neurons secreting the neurohormone GnRH. During development, GnRH neurons migrate from the nasal placode to the hypothalamus by following the terminal nerve to position into the medial preoptic area of the hypothalamus. Once there, GnRH neurons project to the median eminence where the decapeptide is released and transported to the pituitary for the production of gonadotropins, which in turn regulate the production of gonadal sex steroids. Defects in the development or funciton of GnRH neurons lead to hypogonadotropic hypogonadism (HH), a genetic class of disorders due to GnRH deficiency. The genetics of HH is complex and not fully understood with 50% of the cases still unexplained. During the seminar, I will illustrate how Semaphorins, a class of molecules that play key roles during embryonic development and cancer progression, play distinct but essential roles for the correct functioning of the GnRH neuronal system. During the seminar I will also explain how dysfunctional semaphorin signalling can be causing related genetic forms of infertility.