Newer biochemical and pathobiochemical knowledge on the regulation of reproduction and on the influence of nutrition and infection

GnRH is mainly secreted by nerve cells in the mediobasal and in the preopti c area of the hypothalamus, that get informations about the state of nutrit ion and on the influence of stress (e.g. of infections). The secretion is s timulated by leptin, aspartate, glutamate, bradykinin and substance P. Neur opeptide Y (NP Y), corticotropin releasing hormon (CRH), beta -endorphin an d gamma-aminobutyrate have an inhibitory activity. A lack of metabolizable energy lowers the secretion of leptin and augments that of NP Y and CRH. On case of infection several factors inhibit the GnRH-secretion.