Abstract
It is generally accepted that ectopic ACTH-producing tumors produce not only ACTH but β-MSH or β-LPH as well. Using a sensitive radioimmunoassay for βhendorphin, we have demonstrated the presence of β-endorphin immunoreactivity with size heterogeneity according to Sephadex gel chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis in 6ectopic ACTH/β-LPH-producing tumors, providing further evidence for the role of a common precursor to ACTH and β-LPH/β-endorphin in the peptide biosynthesis in these tumors, in a manner similar to the biosynthetic events in the pituitary gland of several species.
