Leptin is a 16 kD product of the ob gene that is produced and released by adipocytes. It plays a key role in metabolism and regulation of adipose tissue. It acts on neurons and hypothalamic receptors thereby influencing the brain’s perception of nutritional energy status and appetite. The absence of functional leptin (or its receptor) leads to uncontrolled food intake and resulting obesity. The Rat Leptin Kit provides assay-specific components for the quantitative determination of both natural and recombinant rat leptin in serum and plasma.