Androgen receptor expression in developing male reproductive organs.

The distribution of androgen receptors (AR) in developing male BALB/c mouse reproductive organs was determined by 3H-dihydrotestosterone steroid autoradiography. The efferent ductules, urogenital sinus (UGS) and Wolffian ducts, and their derivatives, the epididymis, ductus deferens, seminal vesicles, coagulating glands, prostate and bulbouretheral glands, were examined in mice from 13-days fetal (gestation = 19-20 days) to 10 days postnatal. All organs contained AR in their mesenchymal/stromal cells at all times examined. The Wolffian ducts and UGS did not contain epithelial AR on days 13-14 or 16 of gestation. The efferent ductule was the first site of epithelial AR expression in the male tract during development; this organ had epithelial AR on day 16 and at all subsequent times. The epididymis and ductus deferens contained epithelial AR beginning on day 19 of gestation. Seminal vesicle and coagulating gland epithelium was AR- at birth, became weakly AR+ on day 1, and was strongly AR+ on day 2 and subsequently. Prostatic epithelium was AR- up to day 4, when some positive epithelial cells were seen; the prostatic epithelium was strongly AR+ on day 6 and subsequently. The last organ to begin expressing epithelial AR was the bulbouretheral gland; this epithelium did not become clearly AR+ until day 8 postnatally. In summary, these results indicate that initial epithelial AR expression in the male reproductive tract occurs in a clear temporal sequence and proceeds in a cranial-caudal direction. Epithelial AR first appear in the efferent ductules, followed by initial epithelial AR expression in Wolffian-derived organs and finally in the UGS-derived organs. The factors controlling initial epithelial AR expression are unclear, but mesenchyme may be involved.