the occurrence of plasminogen activators of the urokinase-type ( u-pa ) and tissue-type ( t-pa ) at various stages of the epithelial cycle was studied immunohistochemically in rat seminiferous tubule segments . u-pa immunoreactivity was detected exclusively at stages vii and viii in sertoli cells , displaying a distinct granular cytoplasmic staining . t-pa immunoreactivity was found during mid- and late pachytene and diakinesis ( stages vii-xiii ) in spermatogenic cells , displaying a granular cytoplasmic staining with maximal intensity in stages ix-xiii .
C0036630
seminiferous tubule
C1519449
spermatogenic cells