Glutathione peroxidase and selenium levels in the preterm infant.

Glutathione peroxidase (GPX) and selenium are important in the prevention of cellular oxidant damage. Whole-blood GPX and plasma selenium were measured at birth and sequentially afterwards in 75 preterm babies. GPX activity at birth was 2.74 +/- 0.08 (mean +/- SEM) U/ml. Mean GPX activity remained relatively unchanged for up to 70 days postnatal age. Plasma selenium at birth was 0.43 +/- 0.02 (mean +/- SEM) mumol/l), decreasing to low levels by 10 weeks postnatal age. Neither GPX activity nor plasma selenium was related to birth weight, gestational age or infant sex.