title: ACTH receptors in the adrenal: specific binding of ACTH-125I and its relation to adenyl cyclase.
abstract: Pure monoiodo ACTH-(125)I was prepared that was biologically active and free of unlabeled ACTH. Extracts of adrenal cortex that contained ACTH-sensitive adenyl cyclase, bound ACTH-(125)I; extracts that lacked the ACTH-sensitive cyclase did not bind ACTH-(125)I. Unlabeled ACTH inhibited the binding of ACTH-(125)I. Five ACTH derivatives which varied widely in biological activity were tested. All inhibited the binding of ACTH-(125)I in direct proportion to their biological activity. Albumin, insulin, and four unrelated iodinated hormones were inert. The addition of excess hormone or acetic acid produced rapid dissociation of bound ACTH-(125)I. This study demonstrates directly the binding of ACTH to its biologically significant site.
mesh_terms: D000262:Adenylyl Cyclases; D000310:Adrenal Gland Neoplasms / Q000378:metabolism; D000311:Adrenal Glands; D000324:Adrenocorticotropic Hormone; D000818:Animals; D001665:Binding Sites; D001681:Biological Assay; D002628:Chemoreceptor Cells; D007457:Iodine Radioisotopes; D051379:Mice; D009374:Neoplasms, Experimental / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D000324:Adrenocorticotropic Hormone; D000262:Adenylyl Cyclases