Zeta ACTH Antibody. Zeta’s recombinant mouse monoclonal antibody recognizes ACTH (Corticotropin), a 39 amino acid active peptide produced by the anterior pituitary. Zeta’s antibody to ACTH is specific to CLIP (aa 25-39 of ACTH) and does not react with Synacthen (aa 1-24 of ACTH). ACTH results from processing of POMC (pro-opiomelanocortin or corticotropin-lipotropin) is a 267 amino acid polypeptide hormone precursor that goes through extensive, tissue-specific posttranslational processing by convertases. POMC is cleaved into the ten hormone chains: ACTH, NPP, alpha-MSH (Melanocyte Stimulating Hormone), beta-MSH, gamma-MSH, CLIP (corticotropin-like intermediary peptide), Lipotropin-beta, Lipotropin-gamma, beta-endorphin and Met-enkephalin. ACTH is also produced by cells of immune system (T-cells, B-cells, and macrophages) in response to stimuli associated with stress. Zeta’s antibody to ACTH is a useful marker for the classification of pituitary tumors and the study of pituitary disease. The monoclonal antibody to ACTH reacts with ACTH-producing cells (corticotrophs). ACTH may also react with other tumors (e.g. some small cell carcinomas of the lung) causing paraneoplastic syndromes by secreting ACTH.