Abstract
Fetal brain and heart mitochondrial respiratory activity during maternal hypotension was studied in 12 fetal lambs of 120-130 days gestation. Control data were obtained from 16 lambs of comparable gestation. All 28 ewes had low spinal anesthesia. Maternal hypotension was sustained by continuous infusion of trime-taphan camsylate for 60-90 min. Maternal and fetal blood gases were measured prior to and during hypotension. The respiratory activity of isolated brain and heart mitochondria were standardized per mole of cytochrome oxidase determined from the same preparations. In control fetuses brain and heart mitochondrial respiratory activity was 1037 moles of O2 utilized per mole of cytochrome(a + a3) per min. and 1949 moles of O2 utilized per mole of cytochrome(a + a3) per min., respectively. During maternal hypotension fetal blood oxygen tension decreased by a mean of 12 mm Hg from baseline values. Brain and heart mitochondrial respiratory activity decreased to a range of 228-442 moles of O2/mole(a + a3) per min. and 312-400 moles of O2/mole(a + a3) per min., respectively, a significant drop in the metabolic activity(75% in brain and 85% in heart) of the mitochondria. In previous studies we have shown that acute hypoxla does not damage mitochondria when tissue perfusion is well-preserved. The present results suggest that deterioration of fetal mitochondrial respiratory activity is due to a significantly decreased oxygen availability, presumably produced by placental hypoperfusion.
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Delivoria-Papadopoulos, M., Mela, L., Ferguson, J. et al. EFFECT OF INTRAUTERINE HYPOXIA ON MITOCHONDRIAL RESPIRATORY ACTIVITY OF THE FETAL LAMB. Pediatr Res 11, 404 (1977). https://doi.org/10.1203/00006450-197704000-00212
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DOI: https://doi.org/10.1203/00006450-197704000-00212