Effects of Bone Morphogenetic Protein (BMP) on Adrenocorticotropin Production by Pituitary Corticotrope Cells: Involvement of Up-Regulation of BMP Receptor Signaling by Somatostatin Analogs

The mechanism by which somatostatin analogs suppress ACTH production by corticotropinomas has yet to be fully elucidated. We here studied the effects of somatostatin analogs on ACTH secretion using mouse corticotrope AtT20 cells focusing on the biological activity of bone morphogenetic proteins (BMPs). BMP ligands, receptors and Smads, and somatostatin receptors (SSTRs)-2, -3, and -5 were expressed in AtT20 cells. BMP-2, -4, -6, and -7 decreased...