The neuropeptide melanin-concentrating hormone (MCH) plays a key role in energy maintenance by decreasing energy expenditure and stimulating feeding behavior. Furthermore, it is involved in diabetes, gut inflammation, sleep, depression, and cilia beat function. The biological function of MCH is mediated by two G-protein coupled receptors, MCH receptor 1 and 2 (MCHR1 and MCHR2). Since only the MCHR1 is functional in rodents, the physiological importance of MCHR2 remains unknown due to the lack of appropriate animal models. The involvement of the MCHergic system in a variety of pathologies, especially endocrinological diseases, such as obesity and diabetes, makes it interesting as a new target to treat human disorders. Many pharmaceutical companies have pursued the development of MCHR1 antagonists for the treatment of obesity. Moreover, positron emission tomography (PET) tracers targeting the MCHR1 have been developed in order to gain a deeper understanding of the role and distribution of the MCHR1. As a high-end technique, PET allows noninvasive in vivo visualization and quantification of receptor systems, as well as monitoring and following hormone receptor status and related pathologies. Therefore, a MCHR1 PET tracer could help to guide pharmacological intervention via the MCHR1.
Part of the book: Melanin