Comparison of phospholipid indicators of fetal lung maturity in the amniotic fluid of the monkey (Macaca mulatta) and baboon (Papio papio)

The pregnancies of two subhuman primate species, the monkey (Macaca mulatta) and the baboon (Papio papio), were examined to determine if either is a model for human fetal lung development as reflected in amniotic fluid studies. From the data, we suggest that the pregnant rhesus monkey is a model for the study of human lung development. The biochemical pathways for surfactant are the same; the concentrations of lecithin in amniotic fluid correspond closely; there is a parallel rise in L/S ratios which correspond, and the lecithin acyl ester structures and their changes during gestation are very similar. The presence of chronic stress is associated with acceleration of maturation of the surfactant systems of the lung. Although there are some analogies in baboon pregnancy, important differences in lecithin pathway timing and lecithin acyl ester structures make extrapolation to the human subject less tenable. Ligation of the monkey fetal trachea in the second trimester results in oligohydramnios without apparent lung distention. At delivery, the normal changes with age in surfactant biochemistry are not found in the amniotic fluid but are present in lung-bronchial tree washes.