Prohormone processing reactions: discrete stages in the formation of beta-endorphin related peptides.

Analysis of lipotropin from the pars intermedia of bovine pituitary showed that it contained the full COOH-terminal sequence of beta-endorphin. In contrast the beta-endorphin related peptides exhibited a high degree of C-terminal proteolysis. The implications of these findings are discussed with reference to the cellular compartments where the processing reactions take place.