The role of leptin and hypothalamic neuropeptides in energy homeostasis: update on leptin in obesity.

Leptin is an adipocyte-secreted hormone the serum levels of which reflect the amount of energy stored in adipose tissue as well as short-term energy imbalance. Serum levels of many cytokines and hormones also influence circulating leptin levels. Leptin binding to specific receptors in the hypothalamus results in altered expression of orexigenic and anorexigenic neuropeptides that regulate neuroendocrine function and energy homeostasis, and recent experimental evidence suggests that leptin plays an important role in the pathogenesis of obesity and eating disorders. Research that followed the discovery of leptin is significantly broadening our understanding of the mechanisms underlying energy homeostasis, the elucidation of which is expected to result soon in the development of new therapeutic approaches for obesity and eating disorders.