Leptina y hueso: mecanismos moleculares de la interacci n leptina-osteoblasto

Leptin is a polypetidic hormone having 116 amino acids and 14 kD, mainly produced by the white adipose tissue cells. Besides its known anorexigenic role via the SNC and on the adipocyte, regulating the energetic balance, leptin has receptors distributed through multiple tissues and cells of the organism, where it modulates different endocrine axes, acts on sexual development, reproduction, gastrointestinal function, sympathetic activation, modulates hematopoiesis, immunity and stimulates the development of pulmonary cells, and angiogenesis. These pleiotropic actions of leptin are produced on peripheral tissues directly or through a central mechanism, involving a signalling system through the sympathetic nervous system. Actions of leptin have also been described on the bone, where leptin also exerts its actions by two alternative mechanisms: one peripheral, direct, stimulant of bone formation and growth and inhibiting bone resorption and another central, indirect on the hypothalamic level that inhibits bone formation and probably also bone resorption.