Steroid receptor profile and receptor stability in subfractions of human prostatic tissues. Critical aspects on microassays.

Androgen (AR), progesterone (PR), and estrogen (ER) receptor contents in cytosol and salt-extractable nuclear subcompartments from 6 normal, 39 benign hyperplastic (BPH), and 7 malignant prostatic tissue specimens were analyzed by radioligand-binding assay techniques. In addition, the temperature stability of AR and PR was measured in another three BPH specimens. Five punch-needle biopsy samples from prostate cancers were also analyzed for AR and PR content. All receptor data were calculated from saturation analyses. The highest AR content was found in the cytosol and nucleic from malignant prostatic tissues. The highest PR concentrations were found in BPH cytosol, whereas nuclei of all types of tissues were negative with regard to this receptor. Markedly lower concentrations of ER were found in cytosol and nuclei from BPH as compared with malignant and normal tissues. PR was the most temperature-stable receptor; a marked receptor loss at room temperature was not registered until after 12 h. AR was stable for 4-5 h in cytosol and for 8-9 h in nuclei. Needle-biopsy specimens from prostate cancer showed highly variable and confusing results for AR and PR content, indicating that microassay studies using biochemical techniques on small tissue samples are unreliable and should not be recommended.