Characterization of melanin-concentrating hormone from rat hypothalamus.

A melanin-concentrating hormone (MCH)-like peptide was isolated from rat hypothalamus by acid extraction, gel filtration chromatography, immunoaffinity chromatography using antiserum directed against salmon MCH, and two steps of HPLC using octadecyl columns. Several zones of immunoreactivity were isolated, and Edman degradation in a gas phase sequencer indicated that the amino acid sequence of all zones was identical. Rat hypothalamic MCH is a nonadecapeptide which differs from salmon MCH by an N-terminal extension of two amino acids and four additional substitutions. Rat MCH has the following primary structure: Asp-Phe-Asp-Met-Leu-Arg-Cys-Met-Leu-Gly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Gln- Val.