Increase of endothelial nitric oxide synthase and endothelin-1 mRNA expression in human placenta during gestation

Objective: To investigate the maturation of the paracrine system's endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS), endothelin-1 (ET-1) and adrenomedullin (AM) in human placenta during the 2nd and 3rd trimester of pregnancy. Study design: Placental tissue from 14 healthy women with normal pregnancy and from 13 patients giving birth to premature infants following premature labor was obtained. Messenger RNA expression was determined using quantitative TaqMan real-time PCR. Results: Placental eNOS/GAPDH and ET-1/GAPDH mRNA expression significantly increased as a function of gestational age (r = 0.63, P < 0.001 and r = 0.53, P = 0.007, respectively). There was no change in gene expression of neither iNOS nor AM mRNA/GAPDH during gestation (r = 0.02, P = 0.75 and r = 0.001, P = 0.99, respectively). Conclusion: There is a maturation of eNOS and ET-1 in human placenta with gestation reflecting developmental changes of important paracrine endothelial and trophoblastic regulators. AM and iNOS show no maturation during pregnancy. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.