An anterior pituitary Hormone that stimulates the Adrenal Cortex and its production of CORTICOSTEROIDS. ACTH is a 39-amino acid polypeptide of which the N-terminal 24-amino acid segment is identical in all species and contains the adrenocorticotrophic activity. Upon further Tissue-specific processing, ACTH can yield alpha-MSH and corticotrophin-like intermediate lobe peptide (CLIP).