Leptin
The adipocyte hormone that reports fat-store size and restrains appetite.
EndogenousEstablished
Identity
- Class
- Adipokine (167 aa, four-helix-bundle cytokine fold)
- Source
- Adipocytes (white adipose tissue)
- Receptor
- Leptin receptor (LepR / ObR; JAK2-STAT3 signaling)
Key properties
Molecular weight
≈ 16,026 Da
Approximate values for the native hormone. Engineered analogs are often deliberately larger and far longer-acting.
Mechanism
Leptin is secreted from fat in proportion to fat mass and acts on hypothalamic neurons to suppress appetite and permit energy expenditure — a signal of energy sufficiency. In common obesity the signal is high but the response is blunted (leptin resistance), so more leptin does not restore appetite control.
Reference notes
- Leptin is a satiety signal of plenty, not of hunger — low leptin (starvation) drives the strongest behavioral response.
- Leptin resistance, not deficiency, characterizes common obesity; rare congenital deficiency responds dramatically to replacement.
- It links adipose tissue to the same hypothalamic circuits that the melanocortin and incretin systems act on.
Selected literature
Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.
- 1.Leptin and Obesity: Role and Clinical Implication · Frontiers in endocrinology, 2021 · PMID 34084149
- 2.Leptin Function and Regulation · Comprehensive Physiology, 2017 · PMID 29357132