In vitro androgen-induced growth and morphogenesis of the Wolffian duct within urogenital ridge.

Male mouse urogenital ridges (URs) at 15.5 days of gestation (vaginal plug = day 0) containing Wolffian (WDs) and Mullerian ducts were cultured for 4 days with or without gonads in serum-free medium (1:1 mixture of Dulbecco's modified Eagle's medium and Ham's F-12 supplemented with insulin, transferrin, cholera toxin, epidermal growth factor, and BSA). URs without gonads were grown in serum-free medium with testosterone (T, 10(-7) M), 5 alpha-dihydrotestosterone (DHT, 10(-8) M), T (10(-7) M) plus cyproterone acetate (antiandrogen, 10(-5) M), or T (10(-8) M) plus 390 MSD (17 beta-N, N-diisopropylcarbamoyl-4-aza-5 alpha- androstan-3-one, an inhibitor of 5 alpha-reductase, 10(-5) M). After 4 days of culture the number of epididymal curvatures that appeared in the upper portion of WDs were quantified. DNA content of URs grown in serum-free medium was also measured. Both T and DHT increased DNA contents in a dose- (T = 10(-8) to 10(-10) M, DHT = 10(-9) to 10(-11) M) and time-dependent manner. DHT was approximately 10-fold more effective than T in eliciting epididymal coiling and increasing DNA content of URs. The effects of T or DHT were mimicked by coculture with fetal testes. Epididymal coiling and an increase in DNA content occurred in URs grown in the presence of T plus 390 MSD. By contrast, URs cultured without androgens or with T plus cyproterone acetate failed to undergo epididymal coiling and to increase DNA content. The conversion rate per mg protein of [1 beta, 2 beta-3H]T into [3H]DHT was 0.30-fold lower in 15.5 day URs cultured over a 4-day period in comparison to urogenital sinuses whose development is known to be dependent upon DHT. These data suggest that T is an important hormone in the development of the upper portion of WDs, although it is not possible to exclude a role for DHT in the development of the epididymis.