CRH and Cushing syndrome: The mouse model of Cushing's syndrome used in this study was developed in 1992 and is transgenic for the rat corticotropin releasing hormone (CRH) gene downstream of the metallothionein promoter.15 Overexpression of CRH induces the release of ACTH from the pituitary gland, which then stimulates the production of corticosterone from the adrenal gland.