Ovarian plasminogen activator: relationship to ovulation and hormonal regulation.

A technique is described for detecting fibrinolytic activity of single cells in culture. This method was applied to the analysis of rat ovarian granulosa cells. Cells obtained from follicules shortly before ovulation show high levels of fibrinolytic activity. This activity is plasminogen-dependent, indicating that it is due to plasminogen activator. The appearance of this activity is correlated with ovulation by temporal and functional criteria, and can be demonstrated both in immature animals primed with hormones and in mature cycling animals. Granulosa cell cultures can be stimulated to release plasminogen activator by exposure in vitro either to luteinizing hormone or to dibutyryl cyclic AMP.