3 research outputs found
Metabolism of endogenous surfactant in premature baboons and effect of prenatal corticosteroids
We studied the synthesis of surfactant and the effect of prenatal
betamethasone treatment in vivo in very preterm baboons. Ten pregnant
baboons were randomized to receive either betamethasone (beta) or saline
(control) 48 and 24 h before preterm delivery. The newborn baboons were
intubated, treated with surfactant, and ventilated for 6 d. They received
a 24-h infusion with the stable isotope [U-(13)C]glucose as precursor for
the synthesis of palmitic acid in surfactant phosphatidylcholine (PC).
Palmitic acid in surfactant PC became enriched 27 +/- 2 h after the start
of the isotope infusion and was maximally enriched at 100 +/- 4 h. The
fractional synthesis rate of PC palmitate in the beta group (1.5 +/-
0.2%/d) was increased by 129% above control (0.7 +/- 0.1%/d) (p < 0.02,
Mann- Whitney U test). The absolute synthesis rate of PC in the beta group
[1.6 +/- 0.3 micromol/kg/d] was increased by 128% above controls [0.7 +/-
0.2 micromol/kg/d] (p < 0.02). These data show that the synthesis of
endogenous surfactant from plasma glucose as precursor is a slow process.
It is shown, for the first time in vivo, that prenatal
glucocorticosteroids stimulate the synthesis of surfactant PC in the very
premature baboon