POMC (pro-opiomelanocortin), also known as corticotropin-lipotropin, is a 267 amino acid polypeptide hormone precursor that goes through extensive, tissue-specific post-translational processing by prohormone convertases. POMC is cleaved into ten hormone chains named NPP, γ-MSH, ACTH, α-MSH, CLIP (corticotropin-like intermediary peptide), Lipotropin β, Lipotropin γ, β-MSH, β endorphin and Met-enkephalin.

Adrenocorticotropic Hormone (ACTH or corticotropin) is a peptidic hormone synthesized in cells of the anterior pituitary and in neurons in brain. It regulates the corticosteroid production in the adrenal cortex. The primary application of anti-ACTH is in the identification of pituitary tumours and the study of pituitary disease. The Anti-ACTH antibody reacts with ACTH-producing cells (corticotrophs). It may also cause paraneoplastic syndromes by secreting ACTH from other tumors (e.g., some small cell carcinomas of the lung).