Melanin-concentrating hormone (MCH) is a cyclic 19-amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 orexinogenic hypothalamic

Hypothalamus

The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...

 peptide

Peptide

Peptides are short polymers of amino acid monomers linked by peptide bonds. They are distinguished from proteins on the basis of size, typically containing less than 50 monomer units. The shortest peptides are dipeptides, consisting of two amino acids joined by a single peptide bond...

 originally isolated from the pituitary gland

Pituitary gland

In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...

 of teleost fish where it controls skin pigmentation.

In mammals it is involved in the regulation of feeding behavior, mood and energy balance. MCH expressing neurons are located within the lateral hypothalamus and zona incerta. Despite this restricted distribution MCH neurons project widely throughout the brain. MCH knockout mice are hypophagic (eat less) and are lean. When administered centrally it increases food intake and weight gain.