We report the cloning, expression, pharmacological char-acterization and tissue distribution of a melanocortin (MC) receptor gene in a shark, the spiny dogfish (Squalus acanth-ias) (Sac). Phylogenetic analysis showed that this receptor is anorthologof theMC4 subtype, sharing71%overall amino acid identity with the human (Hsa) MC4 receptor. When expressedandcharacterizedbyradioligandbindingassay for the natural MSH (melanocyte-stimulating hormone) pep-tides a-, b-, and c-MSH, the SacMC4 receptor showed pharmacological properties very similar to the HsaMC4 receptor. .
