In the majority of cases (77-87%), the macronodules exhibit ectopic or excessive expression of G-protein coupled receptors, including luteinizing hormone/choriogonadotropin (LH/hCG) responsible for Cushing syndrome during pregnancy and after menopause (70), glucose-dependent insulinotropic peptide (GIP) that is responsible for food-dependent Cushing syndrome (71), serotonin 5HT, catecholamines, Ang II, glucagon and vasopressin (65, 72–77). Here, GCG is linked to Cushing syndrome.