Dissociation between testicular morphogenesis and functional differentiation of Leydig cells.

The aim of the study was to determine whether Leydig cells differentiate in vitro in gonads in which the formation of seminiferous cords is prevented by culture in a medium containing fetal calf serum. Appearance of 3 beta-hydroxysteroid dehydrogenase-positive cells and release of testosterone in the medium occurred at the same age irrespective of whether or not the gonads developed seminiferous cords. It is concluded therefore that testicular morphogenesis with the formation of seminiferous cords is not a prerequisite for the emergence and functional differentiation of Leydig cells.