In vitro development of seminiferous tubules from immature rat testis: ultrastructural and morphometric studies.

Seminiferous tubules from 5 day-old rats maintained in a semi-solid culture system were examined for 4, 8 or 12 days. Morphometric and ultrastructural studies show a significant increase in the seminiferous tubule diameter and normal Sertoli cell differentiation. All the germinal cells degenerate except the spermatogonia.