PDGFD and adrenal cortex adenoma: PDGF receptors are required in the development of steroid-producing cells in multiple organs, including the testis, ovary, and adrenal cortex;11PDGFD is highly expressed in human adrenal gland;12 expression of PDGFD has been negatively correlated with cortisol secretion in adrenocortical adenomas.13 However, the biological mechanisms through which steroids, adrenal cells, and PDGFD interact are not clear.