Newly recognized neuropeptides fulfil a greater and greater part in regulation of fertility. Regulation takes place at every stage of the hypothalamus-hypophysis-ovary axis. Peptides can influence the creation and migration of GnRH neurons and the manner of secretion of GnRH and gonadotropins. Peptides act on the twenty-four-hour variability of secretion and in this instance regulate the biological rhythm of the organism. Peptides also influence homeostasis by regulating body temperature, hunger, sexual impulse, processes of learning and of concentration, etc. Central nervous system and neuropeptides associate signals of biological rhythms, energy content and homeostasis with systems regulating processes of fertility.