Influence of glucocorticoid administration and inhibition on fetal baboon pulmonary maturity and the amniotic fluid L/S ratio

Abstract

The pregnant baboon feto-placental unit responded to intra-amniotic dexamethasone by a rise in the lecithin-sphingomyelin ratio (L/S ratio) and accelerated pulmonary maturity with evidence of increased amounts of pulmonary surfactant. Metyrapone 11 beta-hydroxylase inhibition of corticoid synthesis prevented the expected rise in the L/S ratio without influencing the normal development of pulmonary maturity. The L/S ratio did not accurately reflect pulmonary maturity when metyrapone was administered to the pregnant baboon. Prudently, model systems such as the baboon should be used for more detailed studies of endocrine effects on pulmonary development because of the reported untoward effects of exogenous steroid administration on the human neonatal nervous system.