Single and multiple prenatal glucocorticoid exposures improve preterm newborn lamb cardiovascular and renal function similarly.
OBJECTIVE
Renal and cardiovascular function improves in preterm newborn lambs after a single prenatal betamethasone treatment. We hypothesized that multiple betamethasone exposures would further improve renal and cardiovascular adaptation.


METHODS
Pregnant ewes were chosen randomly to receive saline solution, one dose of 0.5 mg/kg betamethasone at 104 days of gestation, or three doses of 0.5 mg/kg betamethasone at 104, 111, and 118 days of gestation. Lambs were delivered at 125 days of gestation (preterm) or 145 days of gestation (term). Renal and cardiovascular responses to phenylephrine were evaluated at 2 hours of age.


RESULTS
The preterm single and multiple betamethasone-treated lambs comparably increased glomerular filtration rate, urinary flow and osmolar clearance, and sodium excretion in response to phenylephrine. Term responses were similar and not influenced by betamethasone exposure.


CONCLUSIONS
Multiple courses of betamethasone do not further improve renal and cardiovascular responses from a single betamethasone dose. Renal and cardiovascular function at term is not affected by early prenatal betamethasone exposure.
Smith
Lynne M
LM
Department of Pediatrics, University of California, Los Angeles School of Medicine, Harbor-UCLA Medical Center, Torrance 90502, USA. smith@gcrc.rei.edu
Ervin
M Gore
MG
Wada
Norihisa
N
Ikegami
Machiko
M
Jobe
Alan H
AH
D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000097:blood; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D001623:Betamethasone / Q000008:administration & dosage*; D002319:Cardiovascular System / Q000503:physiopathology*; D004334:Drug Administration Schedule; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage*; D007668:Kidney / Q000503:physiopathology*; D007752:Obstetric Labor, Premature / Q000188:drug therapy* / Q000503:physiopathology*; D011247:Pregnancy; D011295:Prenatal Care; D012083:Renin / Q000097:blood; D012756:Sheep
D005938:Glucocorticoids; D000804:Angiotensin II; D000450:Aldosterone; D001623:Betamethasone; D012083:Renin