Retinoid modulation of plasminogen activator production in rat sertoli cells

Tissue type (t) and urokinase type (u) plasminogen activators (PAs) have be en shown to be secreted by Sertoli cells in the seminiferous tubules in a c yclic fashion and to be dependent upon FSH stimulation or upon the presence of adjacent spermatogenic cells. In the present study we have analyzed the production of PAs by retinoid-treated rat Sertoli cells. In addition, beca use retinoids modulate the response of Sertoli cells to FSH either potentia ting or antagonizing its action, we have investigated a possible modulation of FSH-stimulated PA production. Under basal conditions, Sertoli cells, is olated from prepubertal rats, secrete predominantly uPA. A significant dose -dependent inhibition of uPA activity was observed after treatment with ret inol, while no significant effect was detected upon tPA secretion. When Ser toli cells were cultured in the presence of 0.25 mu M retinol, a significan t inhibition of uPA activity was evident after 16 h of treatment and reache d approximately 80% after 48 h of treatment. The analysis of the mRNA level s revealed that retinol induces an inhibition of the steady-state levels of uPA mRNA without affecting those of tPA. Moreover, retinol affected uPA mR NA levels by increasing mRNA turnover. The effect of retinoids on Sertoli c ells isolated from older animals was less evident, possibly due to the redu ced production of uPA with the increase of age of the donor animals. Our re sults on the effect of retinoids upon Sertoli cell uPA production reinforce the importance of retinoids in the control of postnatal testis development .