Plasminogen in peritoneal fluid: a possible nonsteroidal indicator of ovulation.

Plasminogen levels in peritoneal fluid were evaluated in 40 fertile women with regular ovulatory cycles. Fifteen samples were obtained before ovulation and 25 samples after ovulation. Plasminogen content and concentration in postovulatory peritoneal fluid was 0.84 +/- 0.10 mg and 6.1 +/- 0.57 mg/dl, respectively. These values were significantly higher than in the preovulatory peritoneal fluid, which were 0.36 +/- 0.12 mg (P less than 0.005) and 3.5 +/- 0.33 mg/dl, (P less than 0.001), respectively. Estradiol and progesterone (P) concentrations in peritoneal fluid were significantly higher after ovulation (P less than 0.05 and P less than 0.01, respectively). P concentration in serum and peritoneal fluid showed a linear correlation (P less than 0.05). Peritoneal fluid plasminogen is significantly elevated after ovulation and may be a nonsteroidal marker for follicular rupture and oocyte extrusion.