ABSTRACT
Leptin is an adipocyte-secreted hormone that informs the brain about the status o f the body’s energy stores. Leptin controls energy homeostasis through effects on satiety and energy expenditure but also regulates other processes, including reproduction, glycemic control, immune function and wound healing. The leptin receptor exists in multiple alternatively spliced isoforms, o f which only the long form (LEPRb) associates with Janus kinase 2 ( JA K 2) to mediate intracellular signaling. Upon leptin binding, LEPRb initiates multiple intracellular signal trans duction pathways that result in the activation o f STAT family transcription factors, extracellular signal-regulated kinases (ERK), phosphoinositol-3 kinase, AMP-activated kinase and ATP-sensitive potassium channels. This chapter gives a delineation o f our current knowledge about leptin signal transduction, with a particular focus on the role o f individual signaling pathways in vivo and the changes in gene expression induced by leptin.
