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Updated: Jun 25, 2026
Biochemical Measurement of Neonatal Hypoxia
Published on: August 24, 2011
Oxidative challenge and glucose-6-phosphate dehydrogenase activity of preterm and term neonatal red blood cells
Chun Hay Ko1, Raymond Pui-On Wong, Pak Cheung Ng
1Department of Paediatrics, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China.
Insights
Preterm infants have higher glucose-6-phosphate dehydrogenase (G6PD) activity, which inversely correlates with gestational age. Both preterm and term infants show similar antioxidant responses to oxidative stress, indicating effective cellular defenses.
Area of Science:
- Neonatal Physiology
- Biochemistry
- Red Blood Cell Metabolism
Background:
- Preterm infants may have lower antioxidant levels, increasing oxidative stress and hyperbilirubinemia risk.
- Glucose-6-phosphate dehydrogenase (G6PD) activity is notably higher in preterm infants compared to term infants.
Purpose of the Study:
- To assess the oxidative impact of alpha-naphthol on red blood cells from preterm and term infants.
- To investigate the correlation between G6PD enzyme activity and infant gestational age.
Main Methods:
- Quantified G6PD activity in preterm and term infants using a standard diagnostic assay.
- Measured reduced glutathione (GSH) levels before and after incubating whole blood samples with alpha-naphthol.
Main Results:
- Mean G6PD activity was significantly higher in preterm infants (13.52 U/g Hb) than term infants (12.36 U/g Hb).
- A significant negative correlation (r = -0.34) was observed between gestational age and G6PD activity (p < 0.001).
- Alpha-naphthol challenge significantly reduced GSH levels in all infants, with similar percentage reductions across gestational age groups.
Conclusions:
- G6PD activity in G6PD-normal infants negatively correlates with gestational age.
- Erythrocytes from preterm and term infants exhibit comparable responses to alpha-naphthol, suggesting a robust cellular antioxidant pathway involving GSH.
Background:
Recent studies suggest that a low antioxidant level in preterm infants may predispose them to increased oxidative stress and results in hyperbilirubinemia, whereas glucose-6-phosphate dehydrogenase (G6PD) activity was found to be higher in preterm infants than in term infants.
Objectives:
To evaluate (1) the oxidative effect of alpha-naphthol on preterm and term red blood cells, and (2) the relationship between G6PD activity and the gestational age of these infants.
Methods:
G6PD activities were determined in preterm and term infants by a standard diagnostic method. Whole blood samples were incubated with alpha-naphthol for 2 h and their pre- and post-challenged reduced glutathione (GSH) levels were quantified.
Results:
The mean G6PD activity in preterm infants (n = 113; 13.52 +/- 0.19 U/g Hb; gestational age 30.67 +/- 0.28 weeks) was significantly higher than that in term infants (n = 100; 12.36 +/- 0.16 U/g Hb; gestational age 39.82 +/- 0.14 weeks; p < 0.001). A significantly negative correlation was demonstrated between gestational age and G6PD activity (r = -0.34, p < 0.001). GSH levels of preterm and term subjects were similar at baseline, but were significantly decreased upon challenge with alpha-naphthol (p < 0.001). The percentage reduction in GSH levels was similar in the various gestational age groups.
Conclusions:
Our data show that G6PD activities had a negative correlation with gestational age of G6PD-normal infants. The similar response of preterm and term erythrocytes to an alpha-naphthol challenge indicates the manifestation of an active anti-oxidative pathway mediated by cellular GSH.
