Release of tissue‐type plasminogen activator by activated rat eggs and its possible role in the zona reaction

X. Zhang*, J. Rutledge, F. Khamsi, D. T. Armstrong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


The resumption of meiosis results in synthesis of tissue‐type plasminogen activator (tPA) in the rat and mouse oocytes (Haurte et al., Cell 43:551–558, 1985). The present study demonstrates that freshly ovulated rat oocytes released their tPA into the surrounding medium upon in vitro activation by sperm penetration or treatment with a calcium ionophore. The presence of a neutralizing monoclonal anti‐tPA antibody during in vitro activation by the calcium ionophore inhibited the activation‐induced zona hardening and also preserved the ability of the oocyte to be penetrated by sperm subsequent to activation. Rat oocytes undergo zona hardening during in vitro maturation in the absence of serum, presumably as a result of spontaneous cortical granule release, based on findings in mice and hamsters. In the present study, the anti‐tPA antibody prevented the zona hardening and enhanced partition by spermatozoa of rat oocytes that were matured in vitro without serum. Collectively, the observations reported here suggest a possible role of tPA released during the cortical granule reaction in the zona reaction, which contributes to the block to polyspermy.

Original languageEnglish (US)
Pages (from-to)28-32
Number of pages5
JournalMolecular reproduction and development
Issue number1
StatePublished - May 1992


  • Cortical granule reaction
  • Sperm penetration
  • tPA

ASJC Scopus subject areas

  • Genetics
  • Cell Biology
  • Developmental Biology


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