Leptin (LEP)

Leptin is a peptide hormone primarily produced by white adipocytes that plays a central role in regulating body weight, energy homeostasis, appetite suppression, metabolism, reproductive function, bone mass regulation, and immune responses. It acts mainly through the hypothalamus by binding to its specific receptor—leptin receptor (LEP-R), which belongs to the class I cytokine receptor family. Upon binding its receptor on target cells—especially neurons involved in hunger regulation—leptin triggers intracellular signaling cascades such as the JAK/STAT pathway. This leads to changes in neuropeptide expression that suppress food intake while increasing energy expenditure. Leptin also has pleiotropic effects on reproduction and immunity. In most obese individuals circulating levels of leptin are elevated but fail to reduce appetite due to "leptin resistance," limiting its therapeutic use for common obesity. However, recombinant human leptins like metreleptin have been approved for treating rare forms of congenital or acquired lipodystrophy with severe hypoleptinemia. Ongoing research explores additional roles for this hormone across various physiological systems beyond energy balance—including development and immune modulation—and seeks new strategies for overcoming clinical challenges related to resistance mechanisms.

Other names

Obese proteinOb gene productOb proteinGene product, ObLEPTIN (HUMAN)Leptin human

Agonist at the leptin receptor to restore or mimic physiological leptin signaling; activates JAK/STAT pathway leading to transcriptional regulation of appetite and metabolism-related genes.