Nesfatin-1 is an eighty two amino acid, naturally occurring multifunctional protein encoded in the precursor nucleobindin-2 (NUCB2). A comparison of sequences indicates that NUCB2 is present in a number of animals, from hydra to humans. The 30 amino acid mid-segment of nesfatin-1 is considered to be the bioactive core of the protein, and this region displays the highest identity among nesfatin-1 sequences reported thus far. Similar to the sequence relationships observed, the tissue-specific expression and biological actions of nesfatin-1 also appear to be highly conserved across species. For example, brain is a major tissue abundantly expressing nesfatin- 1 in several species. It has been shown that various key regions of the rat, mouse and goldfish brain, which are involved in the regulation of feeding and metabolism express nesfatin-1. Exogenous administration of nesfatin-1 results in a decrease in the food intake of rats, mice and goldfish. In addition, nesfatin-1 has been shown to regulate a number of other physiological processes including hormone secretion from the pancreatic islets and pituitary gland, stress and behavior. While nesfatin-1 research still remains an emerging area in physiology, the literature available thus far clearly shows that nesfatin-1 is an important regulator of homeostasis in animals.