Human or mouse Leptin (from Greek λεπτός leptos, "thin") the "satiety hormone", is a hormone made by adipose cells that helps to regulate energy balance by inhibiting hunger. Leptin is opposed by the actions of the hormone ghrelin, the "hunger hormone". Both hormones act on receptors in the arcuate nucleus of the hypothalamus to regulate appetite to achieve energy homeostasis. ELISA kits and peptides and antibodies are available.