metenkephalin

Metenkephalin is a naturally occurring, endogenous pentapeptide opioid peptide (sequence: Tyr-Gly-Gly-Phe-Met) derived from proenkephalin. It acts primarily as an agonist at the δ-opioid receptor and to a lesser extent at the μ-opioid receptor, with little or no effect on the κ-opioid receptor. Metenkephalin also serves as the endogenous ligand for the opioid growth factor receptor (OGFR), sometimes referred to as the zeta-opioid receptor. Its pharmacological effects include analgesia, neuromodulation, immunomodulation (immunostimulation at low doses and immunosuppression at higher doses), anti-inflammatory activity, antidepressant-like effects, and modulation of gastrointestinal motility. It has been investigated for use in multiple sclerosis (approved in Bosnia), advanced pancreatic cancer, and COVID‑19 due to its immunoregulatory properties[1][3][4][7]. Metenkephalin is rapidly metabolized by several peptidases ("enkephalinases") resulting in a short half-life.

Other names

methionine enkephalinopioid growth factorOGF1–5 Adrenorphin