Characterization of Lipotropin-, Corticotropin-, andβ- Endorphin-Immunoreactive Materials Secreted in Vitro by a Human Pituitary Adenoma Responsible for a Case of Nelson's Syndrome*

Publisher Website
Google Scholar
Abstract
A human pituitary adenoma responsible for a case of Nelson''s syndrome was maintained in organ culture and the incubation medium was examined with 4 different RIA [radioimmunoassay]; human corticotropin (ACTH), .beta.-MSH [melanotropin], lipotropin (LPH) and .beta.-endorphin (.beta.-End). All 4 immunoreactivities (IR) were present in the medium obtained after 24 h of incubation. Gel exclusion chromatography under denaturing conditions (6 M guanidine HCl) revealed several immunoreactive components. Two components with human .beta.-MSH (.beta.-hMSH) and human LPH (hLPH) IR coeluted with .beta.-hLPH and .gamma.-hLPH; a component with .beta.-hMSH IR but no hLPH IR coeluted with [125I].beta.-hMSH; a component with human ACTH (hACTH) IR eluted at the position of hACTH. Sephadex G-50 gel exclusion chromatography revealed that approximately 80 and 20% of human .beta.-End (.beta.-hEnd) IR were accounted for by components coeluting with .beta.-hLPH and .beta.-hEnd, respectively. These data demonstrate the presence in this incubation medium of materials similar to if not identical with .beta.-hLPH, .gamma.-hLPH, hACTH, .beta.-hMSH and .beta.-hEnd; all of these peptides may be secreted in the circulation of patients with Nelson''s syndrome.