Androgen dynamics in vitro in the canine prostate gland.

Abstract

SUMMARY The uptake and metabolism of androgens by canine prostate in vitro were studied by means of an experimental design which consisted of superfusion of prostate slices with a medium containing [4-14C]androstenedione and [6,7-3H]testosterone, or [4-14C]testosterone and 5α-dihydro[1,2-3H]testosterone. The entry or transfer of steroids into the slices, the irreversible metabolism, the conversion between the steroids and their uptake or tissue retention were measured at the steady state. A similar proportion of the three androgens entered the tissue and was irreversibly metabolized. Conversion of testosterone into 5α-dihydrotestosterone was much greater than the interconversion of testosterone and androstenedione. The prostate slices retained 5α-dihydrotestosterone in a concentration up to four times that in the medium, whereas testosterone and androstenedione were retained to a smaller extent. By increasing the steroid concentration in the perfusing medium from 0·03 to 1·30 μmol/l, it was shown that the systems regulating entry, uptake and metabolism of the androgens were not saturated within this range of concentration. No substantial differences were observed in the regulation of tissue—androgen interaction in vitro between five normal and four hyperplastic canine prostates. This was in contrast with previously reported findings that, in man, normal and hyperplastic prostatic tissue respond in a different way to an increase in steroid concentration in the medium.