Leptin and Hormones: Energy Homeostasis.

Leptin, a 167 amino acid adipokine, plays a major role in human energy homeostasis. Its actions are mediated through binding to leptin receptor and activating JAK-STAT3 signal transduction pathway. It is expressed mainly in adipocytes, and its circulating levels reflect the body's energy stores in adipose tissue. Recombinant methionyl human leptin has been FDA approved for patients with generalized non-HIV lipodystrophy and for compassionate use in subjects with congenital leptin deficiency. The purpose of this review is to outline the role of leptin in energy homeostasis, as well as its interaction with other hormones.