Leptin and its mechanism of action

Abstract

Leptin is a hormone produced by the adipose tissue, which has effects on the central nervous system. Leptin is bound to its Ob receptor on hypo-thalamic neurons to inhibit feeding behavior and to increase sympathetically-mediated thermogenesis. In addition to anorexia and thermogenesis, leptin also has direct peripheral and central nervous system-mediated effects on the endocrine, vascular, hematopoietc, immune and musculoskeletal systems. Leptin accomplishes its effects using distributed network of leptin receptors and differential molecular signaling pathways. Leptinemia is increased in obesity because of increased adipocyte mass, but obese subjects exhibit resistance to the anorexic and metabolic effects of leptin. However, multiple studies have shown that leptin can increase sympathetic nerve activity to non-thermogenic tissues in rodents causing obesity-related hypertension. One potential explanation of this paradox is selective leptin resistance. Compared with large and persuasive number of studies on the sympathetic and blood pressure effects of leptin in experimental animals, relatively little attention was given to these effects of leptin in humans. This review article presents recent findings related to leptin and its mechanism of action, and also the role of leptin in patophysiological conditions.