Cosyntropin is a man-made form of a hormone called adrenocorticotropic hormone (ACTH). ACTH is a hormone that is normally produced by the pituitary gland in the brain. ACTH stimulates the adrenal glands to release the hormones cortisol and adrenaline. It is often used during adrenal venous sampling (AVS) to make hormone levels stable and therefore easier to measure reliably.
