Effects of antenatal glucocorticoids on pulmonary vascular reactivity in the ovine fetus.
OBJECTIVE
Although mechanisms of glucocorticoids-induced parenchymal lung maturation have been largely studied, little is known about the pulmonary vascular effects of antenatal glucocorticoids (GCs). We therefore hypothesized that antenatal GCs may alter the hemodynamic response to vasodilatory agents in the fetal lung.


METHODS
We tested the hemodynamic response to acetylcholine, increased PaO(2), and norepinephrine infusion before and after maternal GC administration in chronically prepared, late-gestation fetal lambs (135-137 days of gestational age, term = 147 days).


RESULTS
We found that antenatal GCs (1). do not change the basal pulmonary vascular tone and (2). do not alter the vasodilatory response to acetylcholine and increased PaO (2) but enhanced the norepinephrine-mediated pulmonary vasodilation.


CONCLUSIONS
Our results indicate that antenatal GCs alter the pulmonary vascular reactivity to catecholamines. We speculate that the benefits of antenatal GCs on the cardiovascular adaptation at birth may be related to potentiation of catecholamines vascular effects.
Deruelle
Philippe
P
Department of Obstetrics, Centre Hospitalier Régional Universitaire de Lille, Lille, France.
Houfflin-Debarge
Veronique
V
Magnenant
Eric
E
Jaillard
Sophie
S
Riou
Y
Y
Puech
Francis
F
Storme
Laurent
L
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D005865:Gestational Age; D005938:Glucocorticoids / Q000008:administration & dosage*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008168:Lung / Q000098:blood supply* / Q000196:embryology*; D009638:Norepinephrine / Q000494:pharmacology; D010100:Oxygen / Q000008:administration & dosage; D011247:Pregnancy; D011651:Pulmonary Artery / Q000187:drug effects / Q000196:embryology / Q000502:physiology; D012756:Sheep; D014664:Vasodilation / Q000187:drug effects
D005938:Glucocorticoids; D000109:Acetylcholine; D010100:Oxygen; D009638:Norepinephrine