The adipocyte hormone leptin activates signal transducer and activator of transcription 3
(STAT3) in the hypothalamus, mediating increased satiety and increased energy
expenditure. To date, leptin-mediated activation of the STAT pathwayin vivo has not been
established in tissues other than hypothalamus. We now describe leptin receptor expression
and in vivo signaling in discrete regions of the mouse gastrointestinal tract. Expression of the
functional isoform leptin receptor (OB-Rb) is restricted to the jejunum and is readily detected …