Attenuation of postnatal hypoxia in the premature newborn rat by maternal treatment with dexamethasone: its relationship with lung phospholipid content.

The effect of maternal treatment with dexamethasone on blood PO2, PCO2, pH and lactate concentrations and on lung phospholipid content in premature newborn rats during the early neonatal period was studied. The postnatal hypoxia shown by premature newborn rats was prevented by this treatment. Postnatal hypercapnia was longer in premature newborns showed significantly lower lung phospholipid concentrations than term-delivered newborn animals. Maternal treatment with dexamethasone increased lung phospholipid concentrations which reached values close to those found in term newborns. Our results suggest that maternal treatment with dexamethasone prevents postnatal hypoxia in the premature newborn rat by increasing the lung phospholipid content, which results in an enhancement of oxygen transfer through the alveolar membranes and the attenuation of hyperlactiacidemia.