Corticotrophin-releasing factor and urocortin inhibit system A activity in term human placental villous explants

Plasma corticotrophin-releasing factor (CRF) and urocortin are elevated in preterm labour and/or fetal growth restriction (FGR). FGR is associated with reduced placental system A amino acid transporter activity and in vitro data suggest altered endocrine status could be responsible. Here we test the hypothesis that CRF and urocortin inhibit placental system A activity. Chronic (48 h) exposure of term placental villous explants to these hormones (10 -7 M) significantly reduced system A activity (Na+- dependent 14C-methylaminoisobutyric acid uptake), whereas 1 h exposure had no effect. We propose elevated CRF and urocortin contribute to FGR through negative regulation of placental system A activity. © 2010 Elsevier Ltd. All rights reserved.