Adrenal tumors occur more frequently in women and are the leading cause of Cushing's syndrome during pregnancy. We aimed to evaluate the potential role of sex steroids in the susceptibility of women to adrenocortical tumors. We evaluated the presence of the progesterone receptor (PR), estradiol receptors (ERs), and aromatase in 5 patients with primary pigmented nodular adrenal disease (PPNAD), 15 adrenocortical adenomas (ACAs) and adjacent normal tissues, 12 adrenocortical carcinomas (ACCs), and 3 normal adrenal glands (NA). The expression of PR and ERalpha was evaluated by enzyme immunoassays, real-time RT-PCR, immunohistochemistry, and cytosol-based ligand-binding assays. ERbeta and aromatase levels were evaluated by real-time RT-PCR. ERalpha concentrations were low in NA, in adrenal tissues adjacent to ACA (51+/-33), in ACC (53+/-78), and lower in ACA (11+/-11 fmol/mg DNA). Conversely, PR concentrations were high in NA and adrenal tissues adjacent to ACA, at 307+/-216 fmol/mg DNA, and were even higher in tumors - 726+/-706 fmol/mg DNA in ACA and 1154+/-1586 fmol/mg DNA in ACC - and in isolated PPNAD nodules. Binding study results in four tumors were compatible with binding to a steroid receptor. In patients with PPNAD, a strong positive immunohistochemical signal was associated with the sole isolated nodular regions. ERbeta transcript levels were very high in all samples except those for two ACCs, whereas aromatase levels were low. PR and ERbeta are clearly present in normal adrenal glands and adrenal tumors. Further studies may shed light on the possible pathogenic role of these receptors in adrenal proliferation.