The release of plasminogen activator by rat granulosa cells is highly specific for FSH activity.

The release of plasminogen activator by rat granulosa cells in vitro has been shown to be dependent on the concentration of FSH, and it has thus been proposed as a good assay for this hormone. However, it has been recently claimed that relaxin was also able to trigger the release of plasminogen activator by the same cells. In order to check the specificity of the assay, we studied the behavior of a large number of hormones and we found that it was strictly specific for FSH activity.