[Level of urocortin mRNA during labor and effect of urocortin on myometrial contractility in vitro].

OBJECTIVE: To examine the expression of urocortin mRNA during labor and the effect of urocortin on myometrial contractility, and to investigate its role in the onset and progress of labor. METHODS: (1) Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), using beta-actin as internal standard was applied to determine the levels of urocortin mRNA in human placenta and myometrium from the group of cesarean section before (10 cases) and during (10 cases in latent phase and 10 cases in active phase) labor. (2) The isolated myometrial strips of pregnant women (n = 24) were prepared. The effects of urocortin with or without prostaglandin F(2alpha) (PGF(2alpha)) and oxytocin on myometrial contractility were evaluated by areas under the curve. RESULTS: (1) Semi-quantitative RT-PCR showed that the expression level of urocortin mRNA in placenta and myometrium after the onset of labor were higher than before labor (1.23 +/- 0.52, 1.32 +/- 0.22; 0.83 +/- 0.38, 0.94 +/- 0.13, respectively, P < 0.05). (2) Urocortin itself did not affect myometrial tension development at all concentrations tested, but it markedly increased PGF(2alpha)-induced myometrial contractility. The average area under the curve of controls was (2.12 +/- 0.15) cm(2) and of study strips was (3.90 +/- 0.33) cm(2) (P < 0.05); urocortin did not increase the myometrial response to oxytocin compared with controls (P > 0.05). CONCLUSION: The study indicates urocortin may indirectly modulate myometrial contractility during labor.

[Study on the level of placental urocortin and corticotropin-releasing hormone receptor 2beta of preeclampsia].

OBJECTIVE: To determine the relation between the expression of urocortin and corticotropin-releasing hormone receptor 2beta (CRH-R2beta) in the placenta and pathogenesis of preeclampsia. METHODS: Placentas were collected from 20 pregnant women with preeclampsia as study group and 20 normal pregnant women as control group. Urocortin mRNA and CRH-R2beta mRNA were measured by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Urocortin peptide was measured by immunohistochemistry. RESULTS: (1) The mRNA expression of urocortin was significantly higher (P < 0.05) in preeclampsia (1.14 +/- 0.26) compared with normal pregnancies (0.78 +/- 0.46). (2) There was no significant difference between the expression of CRH-R2beta mRNA of preeclampsia (0.89 +/- 0.33) and of normal pregnancies (0.93 +/- 0.50). (3) The result of immunohistochemistry demonstrated that urocortin was predominantly localized in syntrophoblast with weak staining in cyntrophoblast and capillaries. Urocortin in syntrophoblast of preeclampsia was significantly higher than that of normal pregnancy (P < 0.05). CONCLUSIONS: Our study demonstrates that urocortin peptide and mRNA is increased in women with preeclampsia. This may be a kind of stress-responsive compensatory mechanism in human placenta. Urocortin may play a role in the pathology of the disease.