Wiktionary
neoendorphin
n. Any of a class of naturally-occurring opioid peptides derived from the proteolytic cleavage of prodynorphin.
Wikipedia
Neoendorphin
Neoendorphins are a group of endogenous opioid peptides derived from the proteolytic cleavage of prodynorphin. They include α-neoendorphin and β-neoendorphin.