Current status of prostate androgen receptors.

Over the past eight years, many investigators have attempted to measure androgen receptors in human prostate cytosol and nuclear extracts. It is clear that the concentration of unoccupied cytosol receptors is quite low though measurable if appropriate techniques such as agar gel electrophoresis, sucrose density gradient centrifugation (SDGC) or protamine sulfate precipitation are employed. Attempts to correlate these values in untreated patients with their subsequent response to therapy have not been successful. Recent attempts to measure total cytosol receptors, whose concentration is much higher, have been encouraging and suggest that their determination should be further explored. Measurement of the concentration of nuclear receptors present in salt extracts of nuclei has shown that the level of these receptors is higher than in cytosol and that interference from ligand binding to sex steroid binding globulin or other interfering binding proteins is minimal. It seems likely that greater success in correlating androgen receptors with the clinical response will be achieved from measurements of these nuclear receptors.