Do Sertoli cells influence the microfilament organization of Leydig cells in coculture?

Since it is known that Sertoli cells modulate steroid production by Leydig cells in vitro, an effort was made to see whether the cytoskeleton is involved in this process. Cocultures of Leydig and Sertoli cells were examined in the light microscope equipped with Nomarski optics. To distinguish Leydig cells from Sertoli cells, a histochemical test for delta 5, 3 beta-hydroxysteroid dehydrogenase activity was performed. To visualize microfilaments (MFs), staining with rhodamine labeled phalloidin was used. In coculture, changes of Leydig cell shape towards regular and rounded as well as an increase of androgen production were observed. Concurrently, changes in the microfilament organization were seen. Stress fibers visible in Leydig cells cultured alone, were dispersed or even disappeared when grown in coculture. This effect was strengthened in the presence of FSH in the culture medium, which was not the case in monoculture of Leydig cells. Results are discussed with respect to a possible stimulation of Leydig cell function by Sertoli cells in vitro.