Plasminogen activator inhibitor type 1 in rat spermatozoa: localisation in the tail, in the acrosome and on the surface of the head.

Isolated seminiferous tubules of rat testis contain considerable urokinase-inhibiting activity. An immunohistological analysis revealed the presence of plasminogen activator inhibitor type 1 (PAI-1) in the basement membrane as well as in the interior of the tubules. Distribution and intensity of the intratubular immunoreactivity depends on the stage of the seminiferous cycle.