Intrauterine hypercarbia and lamb lung surfactant synthesis.

Prenatal asphyxia resulting in hypoxia, hypercarbia and amniotic fluid aspiration reduces the synthesis of the pulmonary surfactant. Using 135-day fetal lambs we studied the in utero effects of hypercarbic acidosis alone on fetal breathing activity, excised lung pressure-volume relationships and lamellar body (LB) surfactant disaturated phosphatidylcholine (DSPC) pool size and specific activity for [14C]palmitate. Fetal PaCO2 levels greater than 125 mm Hg for 30 min were associated with pH values less than 7.

Activities of the initial enzymes of glycerolipid and sphingolipid synthesis in lung microsomes from rats exposed to air or 85% oxygen.

Lungs of adult rats exposed to 85% oxygen undergo extensive cellular reorganization; therefore, to investigate changes in lipid metabolism the initial enzymes of glycerolipid and sphingolipid synthesis were measured in lung microsomes. After 1 week of O2 treatment, the specific activity of the glycerol 3-phosphate acyltransferase increased to nearly twice that of the controls and remained elevated for the 3 weeks of study. Serine palmitoyl-transferase activities were approximately the same for both groups.

Rat lung surfactant kinetics biochemical and morphometric correlation.

Biochemical and morphometric techniques were combined to estimate the distribution and flux or rat lung disaturated phosphatidylcholine (DSPC) in surfactant pathways. We found 126 +/- 8 X 10(6) alveolar epithelial type II (AEP II) cells per lung, each containing 150 +/- 30 lamellar bodies (LB). High yields of LB were isolated by centrifugation of lung homogenates with a discontinuous sucrose density gradient.