Purpose 

To review recent advances in the pathophysiology and potential clinical applications of leptin, an adipose tissue-derived hormone.

Data Sources 

A MEDLINE search of the literature on leptin and the bibliographies of relevant papers.

Study Selection 

All 1320 publications on leptin.

Data Extraction 

All identified articles were reviewed.

Cited publications were selected on the basis of study quality and relevance to human obesity and disease.

Data Synthesis 

Leptin is a 16-kilodalton adipocytederived hormone that circulates in the serum in the free and bound form.

Serum levels of leptin reflect the amount of energy stored in adipose tissue.

Short-term energy imbalance as well as serum levels of several cytokines and hormones influence circulating leptin levels.

Leptin acts by binding to specific receptors in the hypothalamus to alter the expression of several neuropeptides that regulate neuroendocrine function and energy intake and expenditure.

Thus, leptin plays an important role in the pathogenesis of obesity and eating disorders and is thought to mediate the neuroendocrine response to food deprivation.

Phase I and II trials recently showed that leptin administration to humans is safe, and ongoing phase III trials are assessing the efficacy of leptin as a treatment for obesity and related disorders. (...)