Subtype-Specific Pharmacological Properties of the Melanocortin Receptors in Chicken

: The melanocortin (MC) receptors belong to the family of G‐protein‐coupled receptors and have five subtypes (MC1‐5) in mammals and chicken. We have expressed the chicken MC1‐5 (cMC1‐5) receptors and seven allelic variants of the cMC1 receptor and performed pharmacological characterization of these receptors. Three variants of the cMC1 receptor, all sharing a Glu to Lys mutation in position 92, are associated with dark feather coloration, and these were pharmacologically described as constitutively active. The pharmacological characterization of the cMC1‐5 receptors provides insight of how this receptor family has evolved and useful information for the use of chicken in physiological experiments.