[Leptin and obesity].

Obesity is associated with increased incidence of cardiovascular diseases, insulin resistance, dyslipoproteinemia and cancer. The discovery of leptin in 1994 has provided a lot of new information about obesity. Leptin is a 167-amino acid peptide synthetized almost exclusively in adipose tissue. This hormone circulates in blood serum in both free and bound forms. The long isoform of leptin receptor is widely distributed in brain, whereas numerous short forms are also being present in peripheral tissues. Leptin acts by binding to the receptors in hypothalamus and altering a release of several neuropeptides, especially neuropeptide Y, regulating energy intake and expenditure. Apart from signaling energy reserves to the brain, leptin promotes hematopoiesis, influences pubertal development and contributes to the increase in arterial blood pressure. Leptin production regulation in humans is poorly understood, but appears to depend on the total body fat, changes in energy intake and serum level of several hormones. Despite the recent advances in the knowledge of both physiology and pathophysiology of leptin, several many important questions require further studies.