Placental expression of enzymes regulating prostaglandin synthesis and degradation

Am J Obstet Gynecol. 2005 Jun;192(6):1836-42; discussion 1842-3. doi: 10.1016/j.ajog.2004.12.070.


Objective: The purpose of this study was to characterize placental expression of the prostaglandin synthase enzymes cyclooxygenase (COX) -1 and -2 and prostaglandin dehydrogenase (PGDH, a degrading enzyme).

Study design: Forty-one women between 20 and 37 weeks' gestation and 39 matched term controls with either spontaneous labor or premature rupture of membranes were enrolled in a prospective case-control study. The relative amounts of placental RNAs at delivery were determined using real-time polymerase chain reaction (PCR).

Results: Placental COX-1 RNA decreased with advancing gestational age at delivery (R(2) = 0.13, P = .001), and increased by 43% when chorioamnionitis was present (P = .006). Among patients presenting at term, oxytocin use was associated with 30% lower expression of COX-1 (P = .01). COX-2 and PGDH were not associated with these variables.

Conclusion: Placental COX-1 RNA at delivery decreases with advancing gestational age and with oxytocin use at term. Thus, expression of placental COX-1 is not constitutive. Placental expression of COX-2 and PGDH do not correlate with gestational age, chorioamnionitis, or oxytocin use.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Case-Control Studies
  • Cyclooxygenase 1
  • DNA Primers
  • Female
  • Fetal Membranes, Premature Rupture / metabolism*
  • Gene Expression Regulation, Enzymologic
  • Gestational Age
  • Humans
  • Hydroxyprostaglandin Dehydrogenases / genetics
  • Hydroxyprostaglandin Dehydrogenases / metabolism*
  • Membrane Proteins
  • Obstetric Labor, Premature / metabolism*
  • Placenta / enzymology*
  • Polymerase Chain Reaction
  • Pregnancy
  • Pregnancy Trimester, Second
  • Pregnancy Trimester, Third
  • Prospective Studies
  • Prostaglandin-Endoperoxide Synthases / genetics
  • Prostaglandin-Endoperoxide Synthases / metabolism*
  • RNA / analysis


  • DNA Primers
  • Membrane Proteins
  • RNA
  • Hydroxyprostaglandin Dehydrogenases
  • Cyclooxygenase 1
  • PTGS1 protein, human
  • Prostaglandin-Endoperoxide Synthases