Synthetic glucocorticoids, like dexamethasone (dex), restrict growth of the fetus and program its adult physiology, in part by altering placental phenotype. The route and timing of dex administration determine the fetal and adult outcomes, but whether these factors affect placental phenotype remains unknown. This study compared placental morphology, amino acid transport, and gene expression in mice given dex orally or by subcutaneous injection over the periods of most rapid placental (Days [D] 11–16) or fetal (D14–19) growth (term is D21). Compared with untreated and saline-injected controls, both dex treatments reduced placental weight at D16 and 19 and fetal weight and total labyrinthine volume at D19 to a similar extent. Only oral dex treatment from D11 to D16 reduced labyrinthine fetal capillary volume on D16 and increased placental 14C-methylaminoisobutyric acid (MeAIB) clearance at D19, 3 days after treatment ended. Neither route of dex treatment altered placental expression of Slc38a, Hsd11b, or the glucocorticoid receptor, Nr3c1, at D16. In contrast, both routes of dex treatment from D14 to D19 increased placental Hsd11b2 expression and labyrinthine maternal vessel volume. Furthermore, injection per se altered placental expression of Nr3c1, Hsd11b1, and specific Slc38a isoforms in an age-related manner. Overall, MeAIB clearance was not related to Slc38a transporter expression but was correlated inversely with maternal corticosterone concentrations when dex was undetectable in maternal plasma at D19. The effects of dex on placental phenotype, therefore, depend on both the route and timing of administration and may relate to local glucocorticoid availability during and after the treatment period.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 89 • No. 4