Synthesis of opiate peptides by a clonal pituitary tumor cell line.

Abstract
Clonal mouse pituitary tumor cells, AtT-20, synthesize at least 4 species of peptides with opiate activity. The endorphin concentration of AtT-20 cells was estimated to be 300-600 pmol/mg of protein. The 2 most abundant endorphins with apparent molecular weights of 1800 and 2400 were purified 300- and 24-fold, respectively; additional minor components were found with apparent molecular weights of > 3000 and < 750.