[Certain properties of estrogen receptors in the cell nuclei of different organs of rats].

Some properties of the macromolecules, specifically binding estradiol (E2) of salt chromatin extracts of the nuclei of the kidneys, liver, prostate, testes and the uterus of rats were studied. Examination of competition of various unlabeled hormonal preparations with 3H-E2 for the binding sites demonstrated the E2-binding macromolecules of the nuclei of all the organs under study to have a high hormonal stereo-specificity. The E2-binding macromolecules of the nuclear extracts of the kidney, liver and the uterus were sensitive to the action of pronase. In sedimentation with ammonium sulfate of proteins from the 0.3 M NaCl extracts of the nuclei of the kidneys and liver, but not of the uterus, the supernatent fraction of the salt-treated extracts showed an additional (in comparison with control) specifically E2-binding macromolecule activity, sensitive to the action of pronase. An analogous effect of the appearance of additional binding activity could be obtained in heating of the nuclear extracts of the kidney and the liver at 60--100 degress C for 5 minutes.