Neuropeptide Y (NPY) and its family of five receptors are known to be associated with hypothalamic regulation of feeding behavior, metabolism, and energy homeostasis in both rodents and humans. In particular, knock-out mice for the gene neuropeptide Y 2 receptor, NPY2R, exhibit hyperphagia and excessive weight gain. As a result, research on the gene has focused on genotyping analysis for the identification of single nucleotide polymorphisms (SNPs) in obese human subjects and drug development for manipulation of its expression as a novel therapeutic treatment for obesity. Although primarily expressed in the arcuate nucleus of the hypothalamus, NPY2R may also be found in other tissues including trabecular bone, vascular tissue, and colonic mucosa.