CRH and Cushing syndrome due to macronodular adrenal hyperplasia: ACTH secretion is stimulated by CRH, and we report a mouse model for Cushing's syndrome due to an N-ethyl-N-nitrosourea (ENU) induced Crh mutation at −120 bp of the promoter region, which significantly increased luciferase reporter activity and was thus a gain-of-function mutation.