This study describes the developmental changes in pulmonary surfactant (PS)
lipids throughout incubation in the sea turtle, Chelonia mydas. Total phos
pholipid (PL), disaturated phospholipid (DSP) and cholesterol (Chol) harves
ted from lung washings increased with advancing incubation, where secretion
was maximal at pipping, coincident with the onset of pulmonary ventilation
. The DSP/PL ratio increased, whereas the Chol/PL and the Chol/DSP ratio de
clined throughout development. The phospholipids, therefore, are independen
tly regulated from Chol and their development matches that of mammals. To e
xplore whether hypoxia could elicit an effect on the development of the PS
system, embryos were exposed to a chronic dose of 17% O-2 for the final sim
ilar to 40% of incubation. Hypoxia did not affect incubation time, absolute
, nor relative abundance of the surfactant lipids, demonstrating that the d
evelopment of the system is robust and that embryonic development continues
unabated under mild hypoxia. Hypoxia-incubated hatchlings had lighter wet
lung weights than those from normoxia, inferring that mild hypoxia facilita
tes lung clearance in this species. (C) 2001 Elsevier Science B.V. All righ
ts reserved.