Effect of maternal isoxsuprine on fetal rabbit lung biochemical maturation.

Isoxsuprine was given intramuscularly for 24 hours to pregnant rabbits at 26 to 27 days' gestation. There was no effect on fetal weight within one day of the last injection. Fetuses of isoxsuprine-treated mothers had higher lung lecithin (6.67 micron per gram +/- 2.81) and higher tracheal wash lecithin/sphingomyelin (L/S) ratios (5.85 +/- 4.5) than did untreated fetuses--lung lecithin (5.35 micron per gram 1.23) and tracheal wash L/S (4.08 +/- 2.3). In contrast, phosphorylcholine glyceride transferase activity of the fetal lung was less in isoxsuprine-treated fetal lung tissue.