Metenkefalin is a peptide hormone that is produced in the brain and is involved in pain modulation. It is also known as endorphin-2 and is a member of the endorphin family of hormones. Metenkefalin plays an important role in the body's response to pain, stress, and emotions. It binds to opioid receptors in the brain and activates them, leading to a reduction in pain intensity. In addition, metenkefalin has been shown to have anti-inflammatory effects and may help reduce anxiety.