By RNA blot analysis, human adrenomedullin mRNA was found to be highly expressed in several tissues including adrenal medulla, ventricle, lung and kidney as well as pheochromocytoma.
Among all the receptors of these peptides that were analyzed, only the AM receptor RDC1 displayed a differential expression between benign and malignant pheochromocytomas.
Both protein kinase A- and C-dependent mechanisms regulate ADM mRNA expression in adrenocortical and pheochromocytoma cells supporting the suggested role for ADM as an autocrine or paracrine (or both) regulator of adrenal function.