http://www.rcsb.org/pdb/ RCSB Protein Data Bank: An Information Portal to Biological Macromolecular Structures Copyright: (C) RCSB PDB http://www.rcsb.org/pdb/skins/web20/images/pdblogo.gif http://www.rcsb.org/pdb/ Wed, 16 May 12 15:56:40 -0700 Wed, 16 May 12 15:56:40 -0700 en-us http://www.rcsb.org/pdb/101/motm.do?momID=149 Wed, 16 May 12 15:56:40 -0700 The delivery of nutrients to cells throughout the body is controlled by a complex network of signaling molecules. Some of these signals happen without us really noticing, for instance, when insulin and glucagon control the level of glucose that is delivered through the blood after we eat. The signaling protein leptin, however, has a more apparent effect, acting within the system that makes us hungry when we need food. http://www.rcsb.org/pdb/101/motm.do?momID=149