The participation of the anorexigenic peptide leptin and the orexigenic peptide ghrelin in the pathogenesis of metabolic syndrome and obesity is well studied. In this review, we are taking a look at the structure, anatomical expression, regulation, receptors and physiological functions of these two neuropeptides. Leptin is produced almost exclusively in adipose tissue. It acts on the brain and is a key element in long-term regulation of energy balance. Leptin suppresses appetite and reduces body weight. Besides its central effects, important aspects of its action on peripheral tissues have been discovered recently: direct regulation of immune cells, pancreatic beta cells, adipocytes and muscle cells. Ghrelin is an endogenous ligand for the active form of the growth hormone receptor (GHS-R1a) and stimulates food intake and growth hormone secretion. We focus on the role of leptin and ghrelin in central nervous system neural mechanisms that are associated with depression. Studying new aspects of these two neuropeptides aims to expand our knowledge of the pathogenesis and therapeutic approaches to diseases with which they are associated: obesity, depression, type 2 diabetes, essential hypertension, and more.
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