Abstract: 11

THE DIFFERENTIAL FATE OF THE MESONEPHRIC TUBULES (EFFERENT DUCTULES) IN ESTROGEN RECEPTOR- KNOCKOUT (ERKO) VERSUS WILD-TYPE (WT) FEMALE MICE.

CS Rosenfeld^{1 *}, PS Cooke^{2 *}, TH Welsh^{3 *}, G Simmer^{4 *}, MG Hufford^{4 *}, RA Hess^{2 *}, DB Lubahn^{1 4}
Dept Animal Science, University of Missouri, Columbia, Missouri ¹
Dept Veterinary Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois ²
Dept Animal Science, Texas A&M University, College Station, Texas ³
Dept Biochemistry & Child Health, University of Missouri, Columbia, Missouri ⁴

Study of sexual development has emphasized androgen induced male differentiation of the Wolffian duct (WD) into the epididymis, ductus deferens, and seminal vesicles, and the mesonephric tubules (MT) into efferent ductules (ED). The WD and MT were believed to degenerate in females due to lack of androgens, though the actual fate of the MT in postnatal females has been relatively overlooked. The present study examined development and fate of MT in female WT and ERKO mice from late fetal to adult life. On gestational day 17, the MT were well developed and morphologically similar to male MT, though only one-third the size of the male structure. Unexpectedly and contrary to the literature, examination of 10-day-old WT (n=5) and ERKO (n=6) female mice revealed ED with cilia in BOTH genotypes. By day 25 on through adulthood, there is a marked phenotypic difference between ED in WT and ERKO female mice. In all of the adult ERKO females examined (n=50), ED are hypertrophied with motile cilia and larger than in adult WT, which only have tiny residual ED. Histologically, the ERKO female ED are dilated with simple columnar to pseudostratified columnar epithelium. Between 10-25 days, ED in ERKO females may be stimulated to develop and/or not regress. The ED might develop in ERKO females because of high levels of testosterone (T). Similar to previously reported T values for older adult ERKO and WT females, preliminary evidence suggests that 25-day-old ERKO have higher T levels (0.903±0.321 ng/ml) (n=6) than WT and heterozygous (0.249±0.030 ng/ml, p<0.01) (n=9) female mice. Surprisingly, DHT did not induce development of ED in WT adult female mice. Thus, the mechanism behind ED development in ERKO females remains uncertain and is currently the subject of further study.

    This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.