LEP and metabolic disease: In metabolic disorders induced by high fat diets, studies investigating the distribution of Fos following central leptin administration have shown a reduction in the number of activated neurons in several hypothalamic areas involved in metabolic and cardiovascular regulation such as the paraventricular nucleus (PVN), supraoptic nucleus (SON), arcuate nucleus (ARC), and the dorsomedial hypothalamus (DMH) (Prior et al., 2010), which may correlate with the reported attenuation of the anorexigenic actions of leptin (Rahmouni et al., 2005).