Role and Involvement of Leptin: Disease and DisordersAuthor(s): Madhukar Saxena, Mayur Sharma and Dinesh Raj Modi
Leptin, a peptide molecule first identified through its role in the hypothalamus regulating food intake and body weight. In addition to the adipose tissue, leptin is expressed in lymphoid tissues, placenta, ovaries, mammary epithelium and bone marrow. Leptin binds to leptin receptor (ObR), which was first isolated from the choroid plexus by expression cloning strategies. ObRs (6 isoforms) are located in the central nervous system and peripheral tissues and show structural similarity with cytokines. Most of the physiological actions of leptin including feeding and energy balance. The other roles of leptin are in reproduction, thermogenesis, synaptic plasticity and neuroprotective effects. In conclusion, this review discusses leptin signaling in different brain areas and sheds light on the involvement of leptin in neurodegenerative disorders. Leptin has neuroplastic and neurotrophic effects and can be definitely useful for treating such diseases. Leptin may have an additional benefit as an insulin sensitizer but, further research is required to elucidate whether leptin sensitizers will be useful and if leptin has a major role in treating brain disorders. Better understanding of the mechanisms mediating leptinÂs neuro developmental actions and increased knowledge about the vulnerability of the brain to leptin level changes is needed.