A peptide of about 41 amino acids that stimulates the release of adrenocorticotropic hormone. CRH is synthesized by neurons in the PARAVENTRICULAR NUCLEUS of the hypothalamus. After being released into the pituitary portal circulation, CRH stimulates the release of ACTH from the pituitary gland. CRH can also be synthesized in other tissues, such as placenta; adrenal medulla; and testis.