Steroid Receptor Content in Cytosol from Normal and Hyperplastic Human Prostates*

Abstract

Analyses of steroid hormone receptors were performedusing a dextran-coated charcoal technique in cytosolicpreparations from 40 cases of benign prostatic hyperplasia(BPH) and 10 normal human prostates. Binding data werecalculated according to Scatchard. In all BPH specimens, receptorsfor the synthetic androgen methyltrienolone (MT) werefound (mean maximum number of binding sites, 566 fmol/mgDNA; mean K_d, 0.61 nM), and 25 of 28 samples containedprogestin [17α,21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione(R5020)] receptors (mean maximum number of binding sites,420 fmol/mg DNA; mean K_d, 0.39 nM). No specimen contained glucocorticoid [dexamethasone (9α - fluoro - 16α - methyl -llβ,17α,21-trihydroxy-l,4-pregnadiene-3,20-dione); n = 16] orestrogen [17β3-estradiol or llβ-methoxy-17α-ethynyl-17α-estradiol(R2858); n = 26] receptors. No correlations were foundbetween receptor content and age of the patients, weight ofadenomas, or percentage of different cell types within the specimens.MT receptors were found in all normal prostates, while5 of the specimens lacked progestin receptors. Estrogen receptorswere found in 3 of the normal prostates, whereas none containedglucocorticoid receptors. The ligand specificity of the MT receptor in a normal prostatewith minor amounts of progestin receptors was typical of anandrogen receptor, and the ligand specificity of the R5020 receptorin a BPH specimen was typical of a progestin receptor. MTand R5020 had approximately the same affinity for the progestinreceptor, whereas the relative binding affinity of R5020 for theandrogen receptor was below 0.02 compared to that of MT. Theandrogen receptor was found to be more stable during repeatedfreezing and thawing than the.progestin receptor.