Immunohistochemistry (IHC) involves the process of selectively imaging antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. Adrenocorticotropic hormone (ACTH) is a peptide hormone produced by the anterior pituitary gland that stimulates the adrenal cortex. It stimulates the adrenal cortex to secrete glucocorticoid hormones, which help synthesise glucose, catabolism proteins, mobilise free fatty acids and inhibit inflammation in allergic responses. The hormone comprises a long chain of amino acids that share a high degree of homology between humans, cows, pigs and sheep.