Melanocortins in sexual function

The melanocortin system is involved in mainly regulatory activity in many physiologic systems. Of the five subtypes of receptors, the MC4R appears most associated with sexual modulation. The MC4R subtype is found in the central nervous system in sites known to be associated with sexual function, and preclinical evidence points to the importance of regions of the hypothalamus. There is no evidence supporting a local direct action on the smooth muscle of the penis. Clinical studies of suitable MC4R agonists appear to confirm that this pathway is a useful target for modulating human sexual function. Recent studies of intranasal PT-141, a cyclic heptapeptide analog, have shown improvements in erection.