Lipid peroxidation in the newborn rat: influence of fasting and hyperoxia on ethane and pentane in expired air.

The rate of lipid peroxidation, as determined by expired air pentane and ethane measurements, was assessed in suckled or fasted newborn rats exposed to air or hyperoxia (FIO2 greater than 0.95). Pentane and ethane production in suckled newborn rats did not significantly change with exposure to hyperoxia after birth. Pentane production averaged over a 3-day exposure period was 2.8 pmol/100 g/min in hyperoxia versus 2.5 pmol/100 g/min in air. However, significant increases in ethane production occurred in fasted newborn rats over the first 18 h of life (less than 2.5 pmol/100 g/min increasing to greater than 6 pmol/100 g/min), which were not observed in suckled animals. Although hyperoxia did not cause an increase in pentane or ethane production above air-exposed controls, nutritional deprivation in newborn rats appeared to accelerate lipid peroxidation events and resulted in high mortality in newborn rats exposed to hyperoxia.