Leptin Physiological Mechanisms in Metabolic Regulation

Leptin is an adipocyte-derived hormone that communicates energy reserve status to the central nervous system, principally acting on hypothalamic neurones to regulate appetite, energy expenditure and neuroendocrine function. Binding of leptin to its long-form receptor (Ob-Rb) activates intracellular pathways such as JAK2–STAT3, PI3K and MAPK, thereby modulating orexigenic and anorexigenic circuits (notably AgRP/NPY and POMC neurones). Through these mechanisms, leptin influences sympathetic tone, lipid metabolism and glucose homeostasis. In energy deficiency, falling leptin levels trigger adaptive responses including enhanced feeding drive, reduced thyroid and gonadal axis activity and conservation of energy. Conversely, in obesity, chronically elevated leptin often coincides with leptin resistance, blunting its regulatory impact. Clinically, leptin replacement is transformative in rare congenital or acquired leptin-deficient states, restoring neuroendocrine axes, improving insulin sensitivity and reducing ectopic lipid accumulation. However, in the broader obese population, leptin therapy has yielded limited benefit, emphasising the complexity of leptin tolerance and the need for strategies to overcome central resistance. Ongoing research explores leptin’s role in diverse conditions—from lipodystrophy and chronic kidney disease to metabolic syndrome and non-alcoholic fatty liver disease—underscoring its global significance and potential as a therapeutic target.

Research from Nature Portfolio

Recent studies have refined understanding of leptin’s effects in lean individuals without genetic defects. Short-term leptin administration following fasting reduces subsequent food intake during refeeding, whereas prolonged treatment lowers fat mass and body weight without increasing energy expenditure or altering lipid utilisation and autonomic indices. Notably, pretreatment leptin levels and administered dose do not predict the magnitude of weight loss, suggesting a saturable response. These findings diverge from rodent data and highlight limits to leptin’s capacity to enhance energy expenditure, thereby informing future therapeutic strategies.

Leptin Physiological Mechanisms in Metabolic Regulation publication trend

The graph below shows the total number of articles in leptin physiological mechanisms in metabolic regulation across all publications each year (not limited to Nature Index journals).

Technical terms

Adipokine: A bioactive peptide secreted by adipose tissue that regulates metabolic and inflammatory processes.

Leptin resistance: A state in which elevated leptin levels fail to elicit expected satiety or metabolic responses.

Lipolysis: The enzymatic breakdown of triglycerides in adipocytes into free fatty acids and glycerol.

Energy expenditure: The total amount of energy used by the body, including basal metabolic rate and activity-related expenditure.

Metabolome: The complete set of small-molecule metabolites present within a biological sample at a given time.

Ob-Rb receptor: The long form of the leptin receptor that mediates intracellular signalling cascades upon leptin binding.

References

1. Starvation in the Midst of Plenty: Reflections on the History and Biology of Insulin and Leptin. Endocrine Reviews (2018).
2. Leptin alters energy intake and fat mass but not energy expenditure in lean subjects. Nature Communications (2020).
3. Leptin-Mediated Changes in the Human Metabolome. The Journal of Clinical Endocrinology & Metabolism (2020).
4. Evidence from clinical studies of leptin: current and future clinical applications in humans. Metabolism (2024).
5. Association of Serum Adipokines and Resting Energy Expenditure in Patients With Chronic Kidney Disease. Frontiers in Nutrition (2022).