IMMUNOHISTOCHEMICAL LOCALIZATION OF ESTROGEN-SPECIFIC 17-BETA-HYDROXYSTEROID OXIDOREDUCTASE IN THE HUMAN AND MOUSE PROSTATE

The estrogen-specific I7 beta-hydroxysteroid oxidoreductase (17 beta-H SOR) enzyme protein was stained immunohistochemically in the newborn a nd adult human prostate as well as in the mouse prostate. In the newbo rn human prostate, ductal and urethral epithelia were faintly stained, whereas in the adult human prostate, intense staining for 17 beta-HSO R enzyme antigen could be detected in the epithelium of the collecting ducts and urethral epithelium as well as in the epithelium of the int raprostatic vas deferens and seminal vesicle epithelium. Immunostainin g was weak in the prostatic tissues of both newborn and adult prostate . No positive cells were found in stroma. The activity of NADPH-depend ent H-3-estrone reductase was detectable in cell-free homogenates prep ared from human prostatic tissues. The activities showed a good correl ation with immunocytochemical findings. In the mouse, neonatal estroge nization resulted in intensively stained epithelium of the collecting ducts at the age of 14 days. Moreover, when adult control and neonatal ly estrogenized mice were implanted with 17 beta-estradiol, the metapl astic epithelium of the periurethral collecting ducts of neonatally es trogenized mice was intensively stained with 17 beta-HSOR. These findi ngs suggest that metaplastic epithelium rises from 17 beta-HSOR-positi ve cells. The similar distributions of 17 beta-HSOR-positive cells con firm the concept of homology in the posterior estrogen-responsive peri urethral region (containing the periurethral ducts and periurethral gl ands) of the mouse and humans. Our findings further suggest that the 1 7 beta-HSOR-positive cells may have the same origin and hormonal contr ol in both species. (C) 1994 Wiley-Liss, Inc.