Specificity: This antibody is specific to Synacthen (aa 1-24 of ACTH); this antibody does not react with CLIP (aa 17-39 of ACTH). Anti-ACTH is a useful marker in classification of pituitary tumors and in the study of pituitary disease. It reacts with ACTH-producing cells (corticotrophs). It also may react with other tumors (e.g. some small cell carcinomas of the lung) causing paraneoplastic syndromes by secreting ACTH. Immunogen: Synthetic peptide corresponding to aa 1-24 of human ACTH