The adipocyte-derived hormone leptin and the pancreatic β cell-derived hormone insulin
each function as afferent signals to the hypothalamus in an endocrine feedback loop that
regulates body adiposity. Although these two hormones, and the receptors on which they
act, are unrelated and structurally distinct, they exert overlapping effects in the arcuate
nucleus, a key hypothalamic area involved in energy homeostasis. Defects in either insulin
or leptin signaling in the brain result in hyperphagia, disordered glucose homeostasis, and …