Adrenocorticotrophic hormone is a polypeptide hormone. It is released from the cells of the anterior pituitary, particularly the corticotrophic cell. Corticotrophic cells are one of the different types of cells in the anterior pituitary. Apart from adrenocorticotropic hormone (ACTH), they also produce and release melanocyte-stimulating hormone (MSH) and lipotropin.
Corticotrophs release ACTH (also called corticotropin) in response to corticotropin releasing hormone (CRH) produced by the neurosecretory cells of the hypothalamus and secreted via the hypophyseal portal system. Thus, it is often produced as a response to biological stress.
The lack of sufficient ACTH may indicate secondary adrenal insufficiency due to an impaired pituitary gland or hypothalamus. The condition may also be associated with tertiary adrenal insufficiency caused by a hypothalamic disease with decreased corticotropin releasing hormone. Excess ACTH, however, is associated with primary adrenal insufficiency, such as in the case of Addison's disease.