Pathology and significance of leptin resistance in obesity

Leptin, the protein product of the ob gene, is predominantly secreted from white adipose tissue, and acts on the brain to regulate food intake, energy expenditure, and neuroendocrine function. Obese rodent and humans are mostly associated with high circulating leptin levels. These findings have led to the conclusion that obese individuals are relatively insensitive to endogenous leptin termed 'leptin resistance'. The potential sites for leptin resistance include the blood-brain-barrier transport system and the leptin signaling mechanism in leptin-responsive neurons in the hypothalamus. In this review, we describe leptin, leptin receptor, and potential hypothesis of leptin resistance.