English: " Leptin is secreted predominantly by the adipose tissue and reaches the brain parenchyma through the bloodstream. The arcuate nucleus of the hypothalamus (ARC) hosts AGRP/NPY and POMC neurons, two distinct antagonistic neuronal populations that have been shown to express Lepr-b (Cheung et al., 1997; Mercer, Hoggard, Williams, Lawrence, Hannah, Morgan, et al., 1996; Mercer, Hoggard, Williams, Lawrence, Hannah, & Trayhurn, 1996). This model proposed that leptin acts directly on those neurons to induce opposite effects. Thus, high leptin levels, signaling a positive energy state, would activate POMC neurons and inhibit AGRP/NPY neurons to promote satiety. On the other hand, low leptin levels would activate AGRP/NPY neurons and inhibit POMC neurons, promoting food intake. Once activated, the first-order AGRP/NPY and POMC neurons would affect second-order neurons, located outside of the ARC, by releasing NPY, AGRP, or POMC-derived α-MSH. Via their action on second-order neurons, these peptides would then induce broad effects on energy homeostasis (Schwartz et al., 2000). AGRP, agouti-related peptide; LEPR, leptin receptor; NPY, neuropeptide Y; POMC, pro-opiomelanocortin; α-MSH, α-melanocyte-stimulating hormone."