The Newest Hormone - Leptin

The Newest Hormone—Leptin
Following discovery of the ob gene in 1994, which codes for this newest hormone, J. Friedman and coworkers soon coined the term, leptin (Gr. leptos, thin), for the circulating hormone, produced by white fat cells (adipose tissue). Subsequently, receptors for leptin have been found in many tissues, but the primary site of action of leptin appears to be the brain, particularly the hypothalamus. Leptin is an important hormone that regulates eating behavior and energy balance as part of a feedback system that informs the brain as to the energy status of the periphery. Leptin has become immensely significant in the study of sateity signals and energy expenditure, since these studies relate to the overall problem of human obesity. It is of interest that blood plasma levels of leptin mirror those of insulin, which also provides an important feedback signal to the brain.