Influence of theophylline on fetal rat lung phosphatidylcholine synthesis in vivo.

In an attempt to resolve conflicting reports on the effectiveness of theophylline in stimulating fetal lung surfactant production in vivo, we examined the influence of theophylline on fetal rat lung phosphatidylcholine synthesis. Intraperitoneal administration of theophylline to the pregnant rat produced elevated serum levels in both mother and fetus. The fetal:maternal ratio was 0.85:0.90. Doses of theophylline ranging between 5 and 180 mg/kg/day resulted in no increase in the rate of incorporation of choline into phosphatidylcholine or its disaturated species. There was also no increase in the lung tissue concentration of these phospholipids. Theophylline does not appear to stimulate fetal rat lung phosphatidylcholine synthesis at nontoxic serum levels.