BACKGROUND: Neuromedin U (NmU) belongs to the neuromedin family, comprising a 
series of neuropeptides involved in the gut-brain axis and including neuromedins 
B and C (bombesin-like), K (neurokinin B), L (neurokinin A or neurotensin), N, 
S, and U.
CONTENT: Although initially isolated from porcine spinal cord on the basis of 
their ability to induce uterine smooth muscle contraction, these peptides have 
now been found to be expressed in several different tissues and have been 
ascribed numerous functions, from appetite regulation and energy balance control 
to muscle contraction and tumor progression. NmU has been detected in several 
species to date, particularly in mammals (pig, rat, rabbit, dog, guinea pig, 
human), but also in amphibian, avian, and fish species. The NmU sequence is 
highly conserved across different species, indicating that this peptide is 
ancient and plays an important biological role. Here, we summarize the main 
structural and functional characteristics of NmU and describe its many roles, 
highlighting the jack-of-all-trades nature of this neuropeptide.
SUMMARY: NmU involvement in key processes has outlined the possibility that this 
neuropeptide could be a novel target for the treatment of obesity and cancer, 
among other disorders. Although the potential for NmU as a therapeutic target is 
obvious, the multiple functions of this molecule should be taken into account 
when designing an approach to targeting NmU and/or its receptors.