Dose effects of antenatal corticosteroids for induction of lung maturation in preterm rabbits.
Dose-response effects of corticosteroids were investigated in the preterm rabbit. Pregnant rabbits were given two doses of 0.01, 0.03, or 0.1 mg of betamethasone per kilogram every 24 hours, beginning on day 25 of gestation. Saline solution was used in a comparison treatment group. Half of the newborn rabbits received supplemental surfactant therapy after delivery via cesarean section on day 27, and all were ventilated on a ventilator-plethysmograph system for 30 minutes. The 0.01 and 0.03 mg/kg regimens had no effect on birth weight or lung function. The 0.1 mg/kg regimen resulted in fetal growth retardation and improved ventilatory measurements, gas exchange, and decreased protein accumulation in the lung, without increasing surfactant pool size. The induction of lung maturation by corticosteroids has multiple targets in the developing lung and does not exhibit a linear dose response.
Tabor
B L
BL
Department of Obstetrics and Gynecology, University of California, Los Angeles Medical Center, Torrance 90509.
Rider
E D
ED
Ikegami
M
M
Jobe
A H
AH
Lewis
J F
JF
D000818:Animals; D000831:Animals, Newborn; D001623:Betamethasone / Q000494:pharmacology*; D001724:Birth Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005325:Fetal Organ Maturity / Q000187:drug effects / Q000502:physiology; D008098:Litter Size / Q000187:drug effects; D008168:Lung / Q000187:drug effects / Q000196:embryology* / Q000502:physiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011663:Pulmonary Surfactants / Q000187:drug effects; D011817:Rabbits; D012119:Respiration / Q000187:drug effects
D011663:Pulmonary Surfactants; D001623:Betamethasone