Antenatal Dexamethasone: Effect on Ovine Placental 11β-Hydroxysteroid Dehydrogenase Type 2 Expression and Fetal Growth
| Autor: | Barbara S. Stonestreet, Leslie S Kerzner, Grazyna B. Sadowska, Ke-Ying Wu, Maureen P Malee |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Hypothalamo-Hypophyseal System
medicine.medical_specialty Hydrocortisone medicine.drug_class Placenta Pituitary-Adrenal System Gestational Age Biology Placebo Dexamethasone Drug Administration Schedule Embryonic and Fetal Development Fetus Pregnancy 11-beta-Hydroxysteroid Dehydrogenase Type 2 Internal medicine medicine Animals Birth Weight RNA Messenger Sheep Reverse Transcriptase Polymerase Chain Reaction Hydroxysteroid Dehydrogenases Gene Expression Regulation Developmental medicine.disease Endocrinology medicine.anatomical_structure Enzyme Induction Pediatrics Perinatology and Child Health Corticosteroid Gestation Female Cortisone medicine.drug |
| Zdroj: | Pediatric Research. 52:706-712 |
| ISSN: | 1530-0447 0031-3998 |
| Popis: | Antenatal glucocorticoids are routinely given to women at risk for preterm delivery. The fetus is protected from excessive glucocorticoids by the placental enzyme 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD-2), which catalyzes the conversion of cortisol to its biologically inactive metabolite, cortisone. We examined the effects of antenatal dexamethasone on the expression of placental 11beta-HSD-2 in fetal sheep. Ewes were randomized to receive repeated or single courses of dexamethasone or placebo beginning at 76-78 or 104-106 d of gestation, respectively. In the single course group, the ewes received dexamethasone (6 mg, n = 7) or placebo (n = 6) as four intramuscular injections over 48 h up to 18 h before placental harvest. In the repeated course group, the ewes received the same treatment (dexamethasone, n = 10, or placebo, n = 9) once a week for 5 consecutive weeks starting at 76-78 d of gestation. Placental harvest occurred at 106-108 d of gestation in the four groups. By semi-quantitative RT-PCR, we found that placental 11beta-HSD-2 expression was lower in the fetuses of ewes exposed to a single course of dexamethasone than placebo (p0.05). Placental 11beta-HSD-2 expression did not differ significantly between fetuses of ewes treated with repeated courses of dexamethasone compared with placebo, or a single course of dexamethasone. Fetuses of dexamethasone treated ewes weighed less than those of placebo treated ewes (ANOVA, main effects for dexamethasone versus placebo treatment: F = 14.5, p = 0.007). Fetuses of ewes exposed to repeated courses of dexamethasone weighed less than those of ewes exposed to placebo or a single course of dexamethasone (p0.05). We conclude that maternal antenatal dexamethasone treatment reduces placental 11beta-HSD-2 expression and fetal weight at mid-gestation in the ovine pregnancy. |
| Databáze: | OpenAIRE |
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