R&D Systems offers products for the study of appetite, an area of research which is closely linked to metabolic disorders and diseases, such as obesity and diabetes. The orexins are neuropeptide hormones derived from proteolytic processing of the same orexin precursor protein. Orexins are named for their appetite-inducing (orexis; Greek for appetite) activity. They are released from the hypothalamus and are involved in the regulation of sleeping patterns, feeding, and metabolism. Another neuropeptide that regulates energy metabolism is Agouti-Related Protein (AgRP), the protein product of the Agouti-Related Transcript (ART).
Hypothalamic expression of AgRP is upregulated in obesity and diabetes, and chronic AgRP administration increases food intake and weight gain in rats. In addition, genetically-linked polymorphisms of AgRP in humans are associated with susceptibility to anorexia nervosa. Further support for genetic vulnerability to obesity was provided when Leptin was identified as a protein product of the mouse obese (ob) gene. Mice with mutations in the ob gene that block the synthesis of leptin have been found to be obese and diabetic and have reduced activity, metabolism, and body temperature.