Antenatal glucocorticoid therapy increases glucose delivery to cerebral circulations during acute hypoxemia in fetal sheep during late gestation.
OBJECTIVE
To determine the effects of 2 maternal injections with dexamethasone on the calculated oxygen and glucose deliveries to fetal cerebral and peripheral circulations during acute hypoxemia in sheep.


METHODS
Beginning at 124 days, ewes received 2 intramuscular injections of either dexamethasone (2 x 12 mg, n = 10) or saline solution (2 x 2 mL, n = 12) 24 hours apart. Hypoxemia (1 hour) was induced 32 hours after the first injection (H1) and 3 days after the second (H2).


RESULTS
In saline solution-treated fetuses, glucose delivery was unchanged or increased in femoral and carotid circulations, respectively, during H1 and H2. In dexamethasone-treated fetuses, the increase in glucose delivery to the head tended to be greater during H1 and was significantly enhanced in dexamethasone- vs saline solution-treated fetuses during H2.


CONCLUSIONS
Two maternal injections with dexamethasone significantly enhanced glucose delivery to the head during acute hypoxemia in the ovine fetus.
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
Juanita K
JK
Jellyman
David S
DS
Gardner
Hugh H
HH
McGarrigle
Abigail L
AL
Fowden
Dino A
DA
Giussani
D000818:Animals; D001921:Brain / Q000196:embryology; D002339:Carotid Arteries / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D003907:Dexamethasone / Q000008:administration & dosage* / Q000097:blood; D005260:Female; D005263:Femoral Artery / Q000378:metabolism; D005333:Fetus / Q000378:metabolism*; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis / Q000502:physiology; D007273:Injections, Intramuscular; D011247:Pregnancy; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D012756:Sheep
D005938:Glucocorticoids; D003907:Dexamethasone; D005947:Glucose