Concomitant production of beta-endorphin in ectopic ACTH/beta-LPH-producing tumors.

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