REGULATION OF TISSUE-TYPE PLASMINOGEN-ACTIVATOR AND PLASMINOGEN-ACTIVATOR INHIBITOR TYPE-1 IN CULTURED RAT SERTOLI AND LEYDIG-CELLS

New data are provided to show that (i) rat Sertoli cells produce two t ypes of plasminogen activators, tissue type (tPA) and urokinase type ( uPA), and a plasminogen activator inhibitor type-1 (PAI-1); (ii) both tPA (but not uPA) and PAI-1 secretion in the culture are modified by F SH, forskolin, dbcAMP, GnRH, PMA and growth factors (EGF and FGF), but not by hCG and androstenedione (Delta(4)); (iii) in vitro secretion o f tPA and PA-PAI-1 complexes of Sertoli cells are greatly enhanced by presence of Leydig cells which produce negligible tPA but measurable P AI-1 activity;(iv) combination culture of Sertoli and Leydig cells rem arkably increases FSH-induced PAI-1 activity and decreases hCG- and fo rskolin-induced inhibitor activity as compared with that of two cell t ypes cultured alone. These data suggest that rat Sertoli cells, simila r to ovarian granulosa cells, are capable of secreting both tPA and uP A, as well as PAI-1. The interaction of Sertoli cells and Leydig cells is essential for the cells to response to hormone stimulation for tPA and PAI-1 secretion.