ABSTRACT
Androgen metabolism and the regulation of rat ventral prostate cell proliferation and secretory function were examined during sexual maturation. Changes in acid phosphatase (AP) characteristics were measured as a marker of androgen-dependent prostatic secretory function. In immature (21-day-old) rats, total AP activity per cell was low (14.2±1.3 mol p-nitrophenol phosphate hydrolysed/h per mg DNA); it increased threefold as the weight, protein and DNA contents of the prostate increased to adult (65-day) levels. This corresponded with significant (P<0.001) increases in the staining intensities of three of the four bands of secretory AP on isoelectric focusing gels. The extent of inhibition of AP by tartrate decreased at the same time. Secretory AP is known to be relatively tartrate-resistant. The changes in AP activity occurred after prostatic 5α-dihydrotestosterone (5α-DHT) levels increased from 4.6 ± 0.7 pmol/mg DNA (21 days) to reach a peak of 17.6±2.3 pmol/mg DNA at 58 days. Prostatic 5α-DHT concentrations were always higher than testosterone levels. Prostatic 5α-androstane-3α,17β-diol (3α-Adiol) levels were lower than 5α-DHT levels except on day 58 when levels peaked dramatically at 26.2±5.5 pmol/mg DNA. Changes in prostatic 5α-DHT and 3α-Adiol levels corresponded with changes in 5α-reductase and 3α-hydroxysteroid oxidoreductase (3α-HSOR) activities. The oxidative reaction of 3α-HSOR was approximately fourfold higher than the reductive reaction, indicating a preference for the formation of 5α-DHT. The plasma levels of testosterone, 5α-DHT and 3α-Adiol cannot account for their respective prostatic levels, indicating the importance of the steroid-metabolizing enzymes in regulating intracellular androgen levels. Changes in the AP characteristics could be correlated with the androgen status of the prostate.
J. Endocr. (1988) 116,81-90
Hoxb13 is required for normal differentiation and secretory function of the ventral prostate
