ERYTHROCYTE CUPRIC ZINC SUPEROXIDE-DISMUTASE EXHIBITS REDUCED ACTIVITY IN PRETERM AND LOW-BIRTH-WEIGHT INFANTS AT BIRTH/

In a comparative study in term, preterm and low birthweight infants, t he mean activity and standard error of the mean for copper/zinc supero xide dismutase (Cu/Zn SOD) in cord erythrocytes from five term small f or gestational age infants was 0.94 +/- 0.10 SOD units (mg protein)(-1 ). This value was significantly lower than the activity (2.34 +/- 0.24 ) in nine term, appropriate for gestational age (AGA) babies (p < 0.00 5). In 15 preterm (AGA) infants, the activity at birth (1.05 +/- 0.07 SOD units (mg protein)(-1)) was also significantly lower(p < 0.001) re lative to term AGA babies. An increased level of activity (1.59 +/- 0. 09) was detected in the red cells of eight preterm AGA infants on thei r expected date of delivery compared with (0.87 +/- 0.06) at birth (p < 0.001). However, the activity (1.59 +/- 0.09) was still lower than t hat detected in term AGA babies (2.34 +/- 0.24; p < 0.02). Similar fin dings were obtained when enzymatic activity was expressed in units per millilitre of packed erythrocytes. The low activity of Cu/Zn SOD in p reterm and low-birthweight babies may render them susceptible to disea ses associated with membrane lipid peroxidation.