Endorphin, << ehn DAWR fihn, >> is any of a group of substances in the nervous system of human beings and animals. Endorphins and closely related chemicals called enkephalins are part of a larger group of morphinelike compounds called opioids. Opioids help relieve pain and promote a feeling of well-being. Scientists believe that endorphins and enkephalins control the brain’s perception of, and response to, pain and stress and may form part of the body’s pain-relieving system.
Scientists have discovered several kinds of endorphins and enkephalins, all of which are peptides (chains of amino acids). Beta-endorphin is one of the most extensively studied opioid peptides. It occurs in the brain and in the pituitary gland, a small gland at the brain’s base, where it may act as a hormone. Beta-endorphin and another hormone called adrenocorticotropin (ACTH) are contained in larger molecules in the pituitary gland. These hormones are split and released as part of the body’s coordinated response to extreme pain or stress.
Scientists believe that opioid drugs produce some of their effects by acting like endorphins and enkephalins. Research chemists have artificially produced endorphins and enkephalins and have studied their use in the control of pain. Although these substances occur naturally in the body, they produce physical dependence when administered as a drug.
