part_of energy homeostasis pathway leptin system pathway Leptin acts on two populations of hypothalamic neurons that express orexigenic (feeding inducing) and anorexigenic genes, respectively. Leptin reduces the expression of genes from the former and enhances the expression of genes from the latter neurons. The leptin mediated response acts primarily via Jak-dependent activation of STAT. PW:0000363 Signaling by Leptin leptin-mediated signaling pathway pathway peptide and protein hormone signaling pathway