Cell surface receptors that bind CORTICOTROPIN; (ACTH, adrenocorticotropic hormone) with high affinity and trigger intracellular changes. Pharmacology suggests there may be multiple ACTH receptors. An ACTH receptor has been cloned and belongs to a subfamily of G-protein-coupled receptors. In addition to the adrenal cortex, ACTH receptors are found in the brain and immune systems.