title: Significant decrease in parathyroid hormone-related protein concentrations in amniotic fluid with labour at term but not preterm.
abstract: It has been determined whether amniotic fluid concentrations of parathyroid hormone-related protein (PTHrP) change with labour. An evaluation of which cells from intrauterine tissues might produce PTHrP has also been conducted. Amniotic fluid was obtained by amniocentesis from women: (1) at term, not in labour; (2) in normal term labour; (3) in preterm labour, undelivered within one week; (4) in preterm labour, delivered within one week; (5) in preterm labour associated with clinical chorioamnionitis; and (6) who were gestation-matched controls for chorioamnionitis patients-women in this group were similar to those in Group 4 but were different patients. Amnion, chorion, and decidual cells were grown by standard techniques and incubated with interleukin-1 beta (IL-1 beta). PTHrP was assayed in duplicate samples of amniotic fluid or tissue culture media using an immunoradiometric assay. There was a significant reduction in amniotic fluid concentrations of PTHrP during labour at term. Preterm labour was not associated with significant changes in amniotic fluid concentrations of PTHrP although a trend for reduced concentrations was observed. Amnion and chorion produced measurable quantities of PTHrP and rates of production were increased by treatment with IL-1 beta. Decidual cells did not produce detectable amounts of PTHrP. Hence, labour at term is associated with a decrease in amniotic fluid PTHrP concentrations that may reflect reduced amnion production, which in turn may play a permissive or active role in the mechanism(s) of parturition. These data support the view that the mechanisms that control term and preterm labour may be regulated differently.
authors.affiliation: Department of Pharmacology and Clinical Pharmacology, University of Auckland, New Zealand.
authors.forename: M D
authors.initials: MD
authors.lastname: Mitchell
authors.forename: C
authors.initials: C
authors.lastname: Hunter
authors.forename: D J
authors.initials: DJ
authors.lastname: Dudley
authors.forename: M W
authors.initials: MW
authors.lastname: Varner
mesh_terms: D000649:Amniocentesis; D000650:Amnion / Q000378:metabolism; D000653:Amniotic Fluid / Q000378:metabolism*; D002478:Cells, Cultured; D002821:Chorioamnionitis / Q000150:complications; D002823:Chorion / Q000378:metabolism; D003656:Decidua / Q000378:metabolism; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007743:Labor, Obstetric / Q000378:metabolism*; D007752:Obstetric Labor, Premature / Q000209:etiology / Q000378:metabolism*; D044162:Parathyroid Hormone-Related Protein; D011247:Pregnancy; D011506:Proteins / Q000378:metabolism*
chemical_list: D007375:Interleukin-1; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins