Expression of plasminogen activator and inhibitor, urokinase receptor and inhibin subunits in rhesus monkey testes

The expression and localization of mRNA's for tissue plasminogen activator(tPA), urokinase PA (uPA), uPA receptor (uPAR) and inhibin subunits, alpha,beta A and beta B in monkey testes was investigated. Using in-situhybridization with digoxigenin-labelled cRNA probes (dig- cRNA), wedemonstrated that tPA and plasminogen activator inhibitor type 1 (PAI-1)were expressed in testes of both immature and mature rhesus monkeys. tPAmRNA was localized predominantly in Sertoli cells. Expression level was lowin immature testis, increased dramatically in the adult and varied withseminiferous cycle. PAI-1 mRNA was localized mainly in germ cells exceptlate spermatids. uPA mRNA was expressed stage-specifically in Sertoli cellsof adult testis. uPA receptor mRNA was localized in germ cells of maturetestis but not in spermatogonia or late spermatids. Assayed by fibrinoverlay technique, PA activity in conditioned media of purified Sertolicells (Sc) was negligible, PA activity in media obtained from co-culturedSertoli and Leydig cells (LS), however, was significantly increased,although Leydig cells alone were not capable of producing any PA activity.Addition of follicle stimulating hormone (FSH) to the incubation mediumremarkably increased PA secretion in both Sc and LS cultures. Human chronicgonadotrophin (HCG) had no significant effect on PA activity in the Scculture but dramatically stimulated PA activity in the co-culture system.Dihydrotestosterone (DHT) did not mimic the effect of HCG. PAI-1 activitywas secreted mainly by germ cells and did not differ between the twoculture systems. FSH and forskolin inhibited PAI-1 secretion. Inhibinalpha, beta A and beta B subunit mRNAs were localized in Sertoli cells ofadult monkey testes, with no obvious difference in the expression levels.These data suggest that PA/PAI-1 and other related factors are expressed inrhesus monkey testis under the control of various hormones, seminiferouscycle and cell-cell interactions through paracrine or autocrine regulation.Locally generated fibrinolysis may play an important role in the process ofspermatogenesis.