The Melanin-concentrating hormone (MCH) is a neuropeptide implicated in a wide range of functions. Its role is best described as an orexigenic peptide since acute MCH applications induce an increase in food intake. MCH-immunoreactive fibers (MCH-ir) are found diffused throughout virtually the entire CNS. In contrast, the production of MCH and messenger RNA (mRNA) from its precursor (ppMCH) is concentrated, in mammals, in neurons of two hypothalamic regions: the lateral hypothalamic area [LHA] and the incerto-hypothalamic area (IHy). Only during lactation, MCH-ir neurons and ppMCH mRNA expression appear in new hypothalamic territories, such as the ventromedial part of the medial preoptic area (vmMPOA). The amount of MCH synthesis in this region increases with the progress of lactation, being maximum in the final phase [around 19th- 21st days] when it disappears. The origin of these cells is still unknown. A possible explanation for this phenomenon is the de novo appearance or neuroplasticity of those cells in the vmMPOA region, which would characterize the necessity of MCH signaling to decline the maternal behavior/lactation period of lactating females.