Antenatal glucocorticoids alter postnatal preterm lamb renal and cardiovascular responses to intravascular volume expansion.
We assessed renal and cardiovascular function in preterm newborn lambs after antenatal glucocorticoid exposure. Pregnant ewes were randomly assigned to receive betamethasone or saline via either direct fetal or maternal injection at 122 d gestation. Lambs were delivered 15 h later, and cardiovascular and renal function was assessed. Two hours after delivery, baseline urine flow, urinary sodium excretion, and urinary osmolar clearance were similar in all groups. Volume expansion (saline, 2.5% of body weight, for 10 min) increased values for urine flow (0.23 +/- 0.04 to 0.58 +/- 0.09 mL x min(-1) x kg(-1)), urinary sodium excretion (29.7 +/- 5.8 to 76.2 +/- 12.3 microEq x min(-1) x kg(-1)), and osmolar clearance (12.2 +/- 1.2 to 24.3 +/- 1.6 mL/100 mL GFR) in the fetal group. Increases in urine values were also observed in the maternal group, but control values did not change significantly. Mean arterial pressure was increased in both betamethasone-treated groups relative to controls. Short-term antenatal betamethasone exposure 1) augments preterm newborn kidney adaptive responses to acute volume expansion, and 2) increases postnatal blood pressure in preterm newborn lambs.
Smith
L M
LM
Department of Pediatrics, University of California, Los Angeles School of Medicine, Harbor-UCLA Medical Center, Torrance 90502, USA.
Ervin
M G
MG
Wada
N
N
Ikegami
M
M
Polk
D H
DH
Jobe
A H
AH
D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000097:blood; D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage*; D001810:Blood Volume / Q000502:physiology*; D002319:Cardiovascular System / Q000196:embryology*; D004983:Ethanolamines / Q000097:blood; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005919:Glomerular Filtration Rate / Q000187:drug effects; D005938:Glucocorticoids / Q000008:administration & dosage; D006439:Hemodynamics / Q000187:drug effects; D007262:Infusions, Intravenous; D007273:Injections, Intramuscular; D007668:Kidney / Q000187:drug effects / Q000196:embryology* / Q000502:physiology; D007752:Obstetric Labor, Premature / Q000188:drug therapy; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012079:Renal Circulation / Q000187:drug effects*; D012083:Renin / Q000097:blood; D012756:Sheep; D012965:Sodium Chloride / Q000008:administration & dosage; D014563:Urodynamics / Q000187:drug effects; D014882:Water-Electrolyte Balance / Q000187:drug effects
D004983:Ethanolamines; D005938:Glucocorticoids; D000804:Angiotensin II; D012965:Sodium Chloride; D000450:Aldosterone; D001623:Betamethasone; D012083:Renin