Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytosol from human benign hyperplastic and carcinomatous prostatic tissue has been shown to contain a progestin receptor with a dissociation constant of approximately 10(-9) M. The receptor was measured using 3H-labeled R 5020 (17 alpha, 21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione) as ligand. Progesterone, cyproterone acetate, and R 1881 (methyltrienolone) were efficient competitors to R 5020 for binding sites on the receptor whereas testosterone, 5 alpha--dihydrotestosterone, estradiol, cortisol, and several hydroxylated and saturated derivatives of progesterone did not compete. The [3H]R 2020-receptor-complex had a sedimentation coefficient of approximately 4 S, an isoelectric point of approximately 5, was heat-labile, and was destroyed by treatment with trypsin but not with deoxyribonuclease or ribonuclease. Seventeen of 21 patients with benign prostatic hyperplasia and three patients with prostatic carcinoma had 1 to 40 fmoles of specific R 5020-binding sites per mg of cytosol protein. One sample of normal prostatic tissue did not contain significant amounts of progesting receptor. Tissue specimens removed by transvesical adenoma enucleation displayed a larger number of specific R 5020-binding sites than electroresected specimens. The progestin receptor in hyperplastic prostate may be involved in the mechanism of the action of progestins used in the medical treatment of benign prostatic hyperplasia. Quantitation of progestin receptor in cancer of the prostate may form part of the basis of a predictive test program for endocrine therapy of prostatic malignancy.
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PMID:Demonstration of a progestin receptor in human benign prostatic hyperplasia and prostatic carcinoma. 7 18

In studies with a synthetic androgen, R 1881, an androgen-binding component was found in the cytosol of human placental villi. Kinetic analysis indicated that the Kd value of this component was 1.4 nM at 0-4 degrees C and that binding of R 1881 amounted to 277 +/- 73 fmol/mg protein. glycerol density gradient ultracentrifugation showed a peak of binding activity in the 8S region in a medium of low ionic strength, but in the 4.5S region in a medium containing 9.5 M KCl. The R 1881-binding component was inactivated by mild heat- or trypsin-treatment, but not by treatment with DNase or RNase. Most of the R 1881-binding activity was sedimented at 20 to 40% saturation of ammonium sulfate. These findings indicate that the R 1881-binding component in human placental cytosol is quite similar in its characteristics to androgen receptors, which are present in various androgen-responsive organs. Testosterone was a more potent competitor of R 1881-binding than DHT or cyproterone acetate. Scatchard plots indicated that the binding site of testosterone was identical with that of R 1881. These findings suggest that the androgen receptor in placental cytosol is specific for testosterone. The Kd value for testosterone was calculated to be 3.2 nM.
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PMID:Androgen receptor in human placental villi. 697 Dec 89