Leptin signaling and energy homeostasis

This chapter focuses on how leptin regulates energy homeostasis via action within the Central Nervous System. Briefly, leptin-activated signaling pathways to drive both changes in transcription and ion channel activity are discussed with a primary focus within the hypothalamus and brainstem. This chapter also describes how leptin signaling in the hypothalamus exerts selective effects on both sympathetic and parasympathetic outflow to peripheral organs while also having effects on autonomic sensory neuron activity. In addition, the importance of leptin signaling within Pro-opiomelanocortin (POMC) and Neuropeptide Y/Agouti-related protein (NPY/AgRP) expressing neurons of the hypothalamus in the control of food intake and glucose homeostasis is reviewed, while also addressing the hypothesis that the principal action of leptin is to regulate metabolism during fasting conditions. Finally, the actions of leptin in the brain, at sites other than the POMC and NPY/AgRP expressing neurons, in the control of metabolic homeostasis are considered.