Androgen metabolism in tissue recombinants composed of adult urinary bladder epithelium and urogenital sinus mesenchyme.

Epithelium of the adult mouse urinary bladder (BLE) was experimentally combined with mesenchyme of the urogenital sinus (UGM) and grown in intact male hosts to produce prostate-like glandular structures. To determine the extent to which the BLE is altered in a functional sense by inductive influences from UGM, investigations into the in vitro metabolism of tritiated testosterone (T) were undertaken. An isocratic high performance liquid chromatographic (HPLC) method was developed in order to separate the metabolites of T in mouse bladder, prostate and UGM + BLE tissue recombinants. Using a C-18 reversed phase column and a tetrahydrofuran (20): methanol (40): H2O (40) mobile phase, efficient and rapid separation of T, dihydrotestosterone, 3 alpha-androstanediol, androstenedione, androstanedione and androsterone was achieved. The identities of the radiolabeled T metabolites were confirmed by recrystallization to constant specific activity. The results of the present study revealed that tissue recombinants expressed testosterone metabolic profiles only partially toward that of the adult prostate. For example, percentage formation of 5 alpha-androstanedione, 3 alpha-androstanediol and unknown polar metabolites in the UGM + BLE resembled the prostate and differed significantly from the urinary bladder. Conversely, formation of the 3 beta-androstanediol and androsterone from testosterone resembled the urinary bladder and differed from the formation of these metabolites in the prostate. These results suggest that in contrast to histomorphology, androgen-induced DNA synthesis, androgen receptor binding activity and total tissue two-dimensional gel electrophoretic protein profiles, androgen metabolic profiles in the tissue recombinants showed only partial transformation into prostatic phenotypes. Analysis of steroid-metabolic profiles, therefore, may represent an exquisite and sensitive method to assess gene expression in various hormone-responsive target tissues.