Electron microscopic studies on mouse Leydig cells in vitro.

The ultrastructure of cultured Leydig cells isolated from mice testes was studied in the early and late phases of culture. Cells were cultured in Leighton tubes on glass evaporated with carbon and covered with Formvar films. Additionally a histochemical test was carried out in order to evaluate the delta 5, 3 beta-hydroxysteroid dehydrogenase activity of Leydig cells in vitro. Levels of androgen released into the culture medium were measured by radioimmunoassay. Both the histochemical and radioimmunological analyses showed high activity of the enzyme studied and a higher androgen level in the first 4 days of culture. During culture a progressive decrease of the steroidogenic function of Leydig cells in vitro as well as some degenerational changes of the cells were observed. The ultrastructural studies showed the difference between Leydig cells in vitro and in vivo and proved the occurrence of the degenerational modifications of cells in the late phase of culture.