Nuclear retention of all steroid hormone receptor classes in the hamster renal carcinoma

The estrogen-induced hamster renal carcinoma contains appreciable amounts of all cytosolic steroid receptor classes sedimenting as 7 to 8S moieties following sucrose gradient centrifugation. Their relative concentrations, expressed in fmol/mg protein +/- S.E. are progesterone (1496 +/- 23) greater than estradiol (218 +/- 3) greater than 5 alpha-dihydrotestosterone (154 +/- 7) greater than dexamethasone (138 +/- 3) greater than aldosterone (40 +/- 2). No cross-competition is apparent for either estrogen or progesterone receptors, but progesterone competes for both androgen and adrenocorticoid binding. These hormone-receptor complexes undergo nuclear translocation using purified tumor nuclei and in tissue minces at elevated temperatures. Salt-extractable nuclear receptors for estrogen (5S), androgen (3.2S), progesterone (2.7S), and corticosteroid (3.5S) have been identified. The existence of five specific steroid receptors within a single tissue is unique and provides a novel model for studying the interrelated actions of all steroid hormones and their therapeutic responses in a hormone-dependent neoplasm.