Leptin (hormone) (LEP)

Leptin is a **peptide hormone** made primarily by white adipose tissue, encoded by the LEP gene, and circulates in blood in free and protein-bound forms[4][8]. It plays a crucial role in regulating energy balance, appetite, and metabolism by signaling satiety primarily in the hypothalamus via the leptin receptor (LEPR or LepRb)[1][2]. Leptin levels reflect body fat stores and show diurnal variation[4][8]. Deficiency or resistance to leptin leads to severe obesity, while exogenous replacement can treat certain congenital leptin deficiencies and lipodystrophy[4][6]. Leptin acts via several major signaling pathways, including JAK2-STAT3, PI3K-AKT, MAPK/ERK, and AMPK, and interacts with other hormonal axes affecting immunity, reproduction, and neuroendocrine functions[1][2][3][5].

Other names

leptin (hormone)obesity factorOB proteinleptin hormone

Exogenous leptin (or analogs) binds to leptin receptor to activate downstream JAK2-STAT3, PI3K-AKT, MAPK, and AMPK pathways, affecting food intake, metabolism, and neuroendocrine axes