Leptin and reproduction

Leptin is a hormone that regulates metabolic efficiency, energy expenditure , and food intake (I). Leptin is secreted by adipose tissue in proportion t o its degree of adiposity, and thus indicates the level of body fat stores. A low leptin level, signifying a paucity of fat, serves as a warning of fo od scarcity and causes animals to conserve fuel. High leptin levels, indica ting excess fuel stores, signal that adipose stores are sufficient for ener gy-demanding activities. Many of the actions of leptin are thought to occur due to its effects on hypothalamic neurons. In this review we will analyze how these hypotheses apply to reproduction.