Immunofluorescent localization of a murine seminal vesicle proteinase inhibitor

The indirect immunofluorescent technique was used to localize a proteinase inhibitor isolated from murine seminal vesicles. The inhibitor was found in the lumen and in the apical epithelium of the seminal vesicle but not in the testes, epididymides, ductus deferens or Cowper's glands. It was also associated with the anterior acrosomal region of ejaculated sperm and sperm recovered from the female tract within 5 min of coitus. The inhibitor is removed from uterine sperm between 2 to 4 h postcoitus, however sperm recovered from the uterus 2 h postcoitus will rebind inhibitor. The inhibitor is not normally associated with epididymal or ductus sperm although these sperm will bind purified inhibitor in vitro.