The role of leptin in the regulation of neuroendocrine function and CNS development.

Leptin, a hormone produced by adipocytes in proportion to fat stores, signals the sufficiency of energy reserves to the brain to control feeding and metabolism. Leptin represents a vital link between metabolic and neuroendocrine pathways, and adequate circulating leptin levels are required to permit the expenditure of energy on reproduction, growth, and other energy-intensive endocrine outputs. Leptin mediates its effects by acting upon a distributed network of CNS neurons that express the signaling form of the leptin receptor (LRb). Nutritional status early in development influences a lifelong metabolic program that modulates risk for diabetes, obesity and other elements of the metabolic syndrome. Recent evidence has demonstrated a number of important roles for leptin in the regulation of neural development and metabolic programming. In this review, we discuss leptin action, the neural circuits on which leptin acts, and our nascent understanding of how early leptin exposure may influence neural development and the predisposition to metabolic diseases.