Effect of aminophylline and caffeine on total and surfactant phospholipid in fetal rabbit lung

Aminophylline treatment of pregnant rabbits for 2 days, beginning at 25.5 days gestation, produced a significant increase in total phospholipid in fetal lung tissue at 27.5 days gestation, 8.92 +/- 0.76 (mean +/- SEM) mg/g wet lung weight, compared with 5.46 +/- 0.83 in saline-injected control animals (p less than 0.005). Three lines of evidence suggest this was not related to the surfactant system: (1) there was no increase in disaturated phosphatidylcholine in fetal lung tissue, (2) there was no increase in total phospholipid harvested by lung lavage after static lung inflation, and (3) there was no change in the lung deflation pressure-volume curve or stability index. Aminophylline treatment produced no acceleration in general anatomic lung development, as reflected in the ratio of lung air-space capacity to lung tissue weight. Under similar experimental conditions, maternal caffeine treatment had no effect on fetal rabbit lungs.