Influence of steroid-receptor complexes on transcription by human hypertrophied prostatic RNA polymerases

Abstract

The effects of 5α-dihydrotestosterone-receptor complexes on transcription in human hypertrophied prostate tissue were studied in a cell-free system reconstituted from the various subcellular fractions prepared from specimens of the diseased gland. Two major RNA polymerase species were isolated from human hypertrophied prostate. These were designated A and B and were distinguishable by their preference for divalent cations and their sensitivity to salt and α-amanitin. Moreover, RNA polymerase B, but not RNA polymerase A, could effectively transcribe a prostate chromatin template. Any enzyme activity endogenous to some chromatin preparations was shown to be characteristic of RNA polymerase B. 5α-Dihydrotestoterone-receptor complexes were transferred into prostatic chromatin both steroid- and tissue-specifically. The association of steroid-receptor complexes with chromatin produced changes in template activity and increased the transcription of the chromatin by exogenous and endogenous RNA polymerase B. With a number of specimens, however, there was considerable variation in accessible cytoplasmic receptor sites, uptake of steroid-receptor complexes by chromatin preparations, the template activity of the chromatin and its response to steroid-receptor stimulation. Nevertheless, the transcription characteristics of human hypertrophied prostatic chromatin appear to be influenced by steroid-receptor complexes, and the extent of the response to added complexes would undoubtedly be governed by pre-existing complexes having had an earlier effect.