LEAP2 Emerges as a Key Hunger-Blocking Hormone With Implications for Obesity and Anorexia
A new review reveals how LEAP2, a ghrelin antagonist made in the liver, regulates hunger, energy balance, and eating disorders.
Summary
LEAP2 (Liver-Expressed Antimicrobial Peptide 2) was discovered as a natural antagonist to ghrelin, the stomach-derived hunger hormone. This review synthesizes nearly two decades of research showing how LEAP2, produced mainly in the liver and small intestine, opposes ghrelin's appetite-stimulating and growth hormone-releasing effects. The two peptides are regulated in opposite directions by energy balance — fasting raises ghrelin while lowering LEAP2, and vice versa. Their ratio may help the brain gauge nutritional status. Importantly, LEAP2 variants are linked to altered eating behaviors, and dysregulation of the ghrelin-LEAP2 axis appears relevant to both obesity and anorexia nervosa, positioning both peptides as compelling pharmacological targets for eating and metabolic disorders.
Detailed Summary
Understanding how the brain and body communicate hunger and satiety is central to addressing the global burden of obesity and eating disorders. Ghrelin, discovered nearly 25 years ago, became famous as the primary orexigenic (appetite-stimulating) gut hormone. However, the identification of LEAP2 as its endogenous antagonist has reshaped thinking about how food intake is centrally regulated via the growth hormone secretagogue receptor (GHSR).
This comprehensive review traces LEAP2's scientific journey — from its original identification as an antimicrobial peptide to its recognition as a metabolic regulator. LEAP2 is synthesized primarily in the liver and small intestine and acts directly on the GHSR to block ghrelin's signals, thereby suppressing appetite, modulating growth hormone secretion, and influencing hedonic (reward-driven) eating.
The authors detail how ghrelin and LEAP2 respond in opposing fashion to both long-term energy balance changes (obesity vs. fasting/caloric restriction) and short-term meal-related nutrient intake. This dynamic ratio likely serves as a continuous metabolic signal to hypothalamic circuits governing hunger and reward. Genetic variants in LEAP2 appear to influence its circulating levels and function, with potential links to abnormal eating behaviors.
Clinically, the review highlights two key pathological contexts: obesity, where elevated LEAP2 may suppress appetite signaling, and anorexia nervosa, where low LEAP2 alongside elevated ghrelin may perpetuate a paradoxical resistance to hunger cues. Both conditions may benefit from pharmacological strategies targeting the ghrelin-LEAP2-GHSR axis.
As a review based solely on the abstract, specific quantitative findings and individual study details are not available. Nonetheless, the synthesis underscores LEAP2 as a promising, underexplored target in metabolic and psychiatric medicine.
Key Findings
- LEAP2, produced in the liver and small intestine, acts as an endogenous antagonist at the ghrelin receptor (GHSR), suppressing appetite.
- Ghrelin and LEAP2 respond inversely to energy balance — fasting elevates ghrelin and lowers LEAP2, feeding does the opposite.
- LEAP2 opposes ghrelin's effects on food intake, growth hormone secretion, hedonic feeding, and glucose homeostasis.
- Genetic variants in LEAP2 are associated with altered eating behaviors and may influence metabolic disease risk.
- Both obesity and anorexia nervosa involve dysregulation of the ghrelin-LEAP2 axis, making it a dual pharmacological target.
Methodology
This is a narrative review article synthesizing published literature on LEAP2 biology and its relationship to ghrelin signaling. It covers basic characterization, physiological regulation, genetic variants, and disease associations. No original experimental data were generated by the authors.
Study Limitations
This summary is based solely on the abstract; specific data, effect sizes, and individual study findings are unavailable. As a review, conclusions depend on the quality and scope of the underlying cited literature. The clinical translation of LEAP2-targeted interventions remains early-stage and largely preclinical.
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