ENDOTHELIN-1 GENE-EXPRESSION IN HUMAN PHEOCHROMOCYTOMA

We examined expression of human endothelin-1 (ET-4) in adrenal tissues removed from five patients with pheochromocytomas and two patients wi th aldosterone-producing adenomas. The pheochromocytomas contained a 2 .3 kilobase ET-1 transcript, which was not found in the aldosteronomas . Constitutive expression of ET-1 varied in magnitude among the pheoch romocytomas but was generally at a low level. Immunohistochemical stai ning of the pheochromocytomas with an antiserum to human ET-1 showed t he presence of immunoreactive ET-1 as well. The presence of ET-1 messe nger ribonucleic acid and ET-1 immunoreactivity in human pheochromocyt omas suggests a possible paracrine role for this peptide in human chro maffin cells.