FGL2 prothrombinase messenger RNA expression in gravid and nongravid human myometrium

Objective: Thrombin is a potent uterotonic agent that may play an important role in human parturition. FGL2 is a prothrombinase that cleaves prothrombin to thrombin. The purpose of this study was to determine FGL2 messenger RNA expression in human myometrium and to assess its relationship to the expression of EP3-6 prostaglandin receptor and inducible nitric oxide synthase. Study Design: Myometrium was obtained from gravid women who underwent cesarean delivery (n = 19), from premenopausal (n = 10) and menopausal (n = 10) women who underwent hysterectomy, and from nonpregnant women who received 200 mg of misoprostol vaginally 12 hours before hysterectomy (n = 8). FGL2 messenger RNA expression was determined with the use of semiquantitative polymerase chain reaction and was compared with previously determined messenger RNA expression levels for EP3-6 and inducible nitric oxide synthase for the same samples. Statistical analysis was performed with the use of independent t test, Fisher exact test, analysis of variance, and linear regression, where appropriate. Results: All samples that were analyzed contained demonstrable quantities of FGL2 messenger RNA. The highest FGL2 expression was found in gravid women, followed by women who were treated with misoprostol, by premenopausal nonpregnant women, and by menopausal women (P< .0001, analysis of variance). Significantly higher levels of FGL2 expression were found in the gravid women compared with the women who were treated with misoprostol (P< .001), the premenopausal nonpregnant women (P< .001), and the menopausal women (P< .0001). FGL2 messenger RNA expression correlated with EP3-6 and inducible nitric oxide synthase expression in all samples combined (r = 0.55, P< .0001; and r = 0.67, P< .001, respectively). Conclusion: The expression of FGL2 messenger RNA is increased in gravid myometrium compared with nonpregnant samples. Its expression significantly correlates to EP3-6 and inducible nitric oxide synthase expression. FGL2 prothrombinase expression may mediate the role of thrombin in human parturition. (Am J Obstet Gynecol 2003;188:1057-62.)