MCH may act as a nerotrasmitter or mertomodulator in goal-directed behavior, such as food intake, and general arousal and possibly in spermatocyte differentiation.Human, Mouse, Rat: H-Asp-Phe-Asp-Met-Leu-Arg-Cys-Met-Leu-Gly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Gln-Val-OH (Cys7--Cys16) or H-DFDMLRCMLGRVYRPCWQV-OH (Cys7--Cys16)