Quantitative Aspects of Oxygen Toxicity in the Newborn: Inhibition of Lung Dna Synthesis in the Mouse

The incorporation of 3H-thymidine into lung DNA in newborn mice was inhibited by increasing exposure to 96-100% oxygen. Twenty-four hours following the onset of this inhibition both total DNA per lung and lung weight decreased in the oxygen-exposed animals relative to the air-exposed control animals. These data indicate that 96-100% oxygen retards lung growth in the newborn mouse by inhibiting DNA synthesis and cell replication. These results are consistent with observations on cultured cells of nonpulmonary origin. Such growth inhibition may occur at oxygen concentrations below 96 -100%.