Journal of Applied Physiology, Vol 48, Issue 3 505-510, Copyright © 1980 by American Physiological Society
Effect of prenatal isoxsuprine on pulmonary oxygen toxicity in the newborn rat
L. Frank, J. Summerville and D. Massaro
Isoxsuprine, a beta-sympathomimetic agent used clinically to delay
premature parturition and to possibly accelerate fetal lung maturation, was
administered to pregnant rats at 48 and 24 h prior to delivery. Newborn
rats were placed in 96-98% O2 (or room air) to determine if the prenatal
isoxsuprine treatment compromised their tolerance to prolonged hyperoxic
exposure. (Exogenous catecholamines are known to exacerbate O2 toxicity in
adult animals). Survival of the isoxsuprine-treated pups in O2 (52%) was no
different than for control neonates exposed to hyperoxia for 7 days (57%)
(P = 0.22). Body weight, lung weight, lung protein, and DNA content of the
newborns were also not altered by the prenatal isoxsuprine treatment. Lung
antioxidant enzyme activities for superoxide dismutase, catalase, and
glutathione peroxidase were the same at birth in the isoxsuprine-treated
and control rat pups, and the enzyme activities increased in response to
hyperoxic exposure in each group to an equivalent degree. Thus, in utero
treatment with isoxsuprine had no apparent adverse effect on newborn rats
exposed to a prolonged O2 challenge.
