Leptin gene expression in the brain and pituitary gland

The adipocyte-derived hormone, leptin, and its receptor, are now known to b e integral components of a physiological signalling system that regulates f uel stores and energy balance. Constitutive leptin expression has been demo nstrated only in adipose tissue, placenta and stomach. We have used RT-PCR to show that leptin mRNA is selectively transcribed in specific areas of ra t brain and pituitary, and in a rat glioblastoma cell line. Using immunocyt ochemistry we have also shown leptin protein immunoreactivity in the corres ponding tissues and cells, and confirmed this by Western blot using two epi tope-specific antisera. Leptin mRNA expression in the hypothalamus is suppr essed by fasting (48hr), suggesting a role for brain leptin in the central regulation of appetite. These data support the hypothesis that central nerv ous system derived leptin is a likely ligand for central leptin receptors.