Biochemical analysis of teleost melanin-concentrating hormone

A series of experiments was conducted to examine the gross biochemical nature of melanin-concentrating hormone (MCH) by utilizing a reliable and simple ^H vivo bioassay. Boiling and trypsin digestion of cod pituitary homogenate supernantant containing MCH destroyed the MCH activity. Dialysis indicated MCH was between 3,500 and 13,000 rr.olecular weight. MCH is a cation; as it bound to CM cellulose but did not bind to DEAE cellulose. Disulfide bonds apparently were not present in MCH since sodium borohydride did not disrupt MCH activity. In the Killifish, MCH activity was not found in the brain. Evidence presented here suggests -MCH is a small positively charged polypeptide containing no disulfide bonds.