Adrenorphin

Adrenorphin, also sometimes referred to as metorphamide, is an endogenous, C-terminallyamidated, opioidoctapeptide (Tyr-Gly-Gly-Phe-Met-Arg-Arg-Val-NH₂, YGGFMRRV-NH₂) that is produced from proteolyticcleavage of proenkephalin A and is widely distributed throughout the mammalianbrain. It was named based on the fact that it was originally detected in humanphaeochromocytomatumour derived from the adrenal medulla, and was subsequently found in normal human and bovine adrenal medulla as well. Adrenorphin exhibits potent opioid activity, acting as a balanced μ- and κ-opioid receptoragonist while having no effects on δ-opioid receptors. It possesses analgesic and respiratory depressive properties.