Polymerization of deoxyribonucleotides in relation to androgen-induced prostatic growth

Massive yet transitory elevations in the DNA polymerase activity of soluble ventral prostate extracts occur as a result of daily treatment of castrated rats with large doses of androgens. Evidence is presented that the enzymic processes measured are catalyzed mainly by a "replicative" type of DNA polymerase which preferentially utilizes single-stranded DNA's as primers. The androgen-induced changes in prostatic DNA polymerase in castrates were compared with corresponding alterations in the incorporation of labeled precursors into DNA as promoted by intact prostatic cells both in vivo and in vitro, and with the net accumulation of total prostatic DNA which accompanies growth of the gland under these conditions. Administration of large doses of testosterone to normal rats results in only small increases in prostatic DNA content and DNA polymerase activity. It appears that high levels of prostatic DNA polymerase are demonstrable only around the times that prostatic cells are actively engaged in DNA synthesis. These findings are discussed in relation to the relative contribution of cell proliferation to the overall growth of androgen-sensitive tissues, and to mechanisms which may regulate the eventual limitation of prostatic growth in situ that occurs despite excessive hormonal stimulation.