A peptide antagonist of MC1R MC3R MC4R and MC5R (IC50s 19.5 0.59 13.58 and 8.07 nM respectively for the human receptors) an antagonist of dog MC1R MC3R MC4R and MC5R receptors (IC50s 53.64 1.46 7.14 and 11.22 nM respectively) increases food intake and body weight in a rat model of LPS-induced cachexia at 10 mg/kg increases body weight muscle mass blood urea nitrogen levels and the mean heart rate in dogs with cachexia at 0.75 mg/kg per day