Androgen-dependent mechanisms of Wolffian duct development and their perturbation by flutamide.
Androgens play a vital role in Wolffian duct (WD) development, but the mechanisms that underlie this are unknown. The present study used in utero exposure of pregnant rats to the androgen receptor antagonist flutamide (50 or 100 mg/kg) to explore possible mechanisms. Pregnant rats were treated from embryonic d 15.5 (E15.5), and WDs were isolated from fetuses from E17.5-E21.5 and from adults. WD morphology was evaluated, and total length of the duct lumen was determined in fetal samples. Fetal WDs were immunostained for androgen receptor and stromal (inner and outer) and/or epithelial-cell-specific markers and analyzed for cell proliferation and apoptosis. In adulthood, most flutamide-exposed males lacked proximal WD-derived tissues, whereas at E18.5-E19.5, a time when the WD has completely regressed in females, a complete normal WD was present in all flutamide-exposed animals. This suggests that flutamide, at doses of 50 or 100 mg/kg, interferes with WD differentiation, not stabilization. Consistent with this, WD elongation/coiling increased in controls by 204% between E19.5 and E21.5 but increased less significantly (103%) in flutamide-exposed animals. This was associated with reduced cell proliferation, but there was no increase in apoptosis or change in expression of androgen receptor mRNA or protein. Flutamide treatment impaired differentiation of inner stromal cells, shown by decreased expression of smooth muscle actin, before effects were noted in the epithelium, consistent with androgens driving WD development via stromal-epithelial interactions. In conclusion, WD differentiation is far more susceptible to blockade of androgen action than is its initial stabilization, and these effects may be mediated by disruption of stromal-epithelial interactions.
Welsh
Michelle
M
MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, Scotland, United Kingdom. m.welsh@hrsu.mrc.ac.uk
Saunders
Philippa T K
PT
Marchetti
Nicholas I
NI
Sharpe
Richard M
RM
D000726:Androgen Antagonists / Q000494:pharmacology*; D000728:Androgens / Q000502:physiology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000648:ultrastructure; D005260:Female; D005455:Fluorescent Antibody Technique; D005485:Flutamide / Q000494:pharmacology*; D005837:Genitalia, Male / Q000187:drug effects / Q000254:growth & development; D007150:Immunohistochemistry; D008297:Male; D008938:Mitosis / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017208:Rats, Wistar; D011944:Receptors, Androgen / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000187:drug effects; D014928:Wolffian Ducts / Q000187:drug effects / Q000254:growth & development*
D000726:Androgen Antagonists; D000728:Androgens; D011944:Receptors, Androgen; D005485:Flutamide