Erythrocyte enzyme activities in cord blood of extremely low-birth-weight infants

To investigate the features of erythrocyte metabolism in extremely immature infants, we assayed 21 enzyme activities and glutathione level in cord ery throcytes from 28 extremely low-birth-weight infants (ELBWI; defined as bir th weight <1,000 g). The results were compared with those from normal adult s and non-neonatal reticulocyte-rich controls. Statistical analysis reveale d that activities of six enzymes (glucosephosphate isomerase, phosphoglycer ate kinase, monophosphoglycerate mutase, enolase, glucose-g phosphate dehyd rogenase (G6PD), and glutathione reductase) were significantly higher, and those of eight other enzymes (phosphofructokinase, 6-phosphogluconate dehyd rogenase (6PGD), glutathione peroxidase, adenylate kinase, adenosine deamin ase, acetylcholinesterase, NADH methemoglobin reductase, and catalase) were lower in ELBWI taking their marked reticulocytosis into consideration. The 6PGD/G6PD ratio, which is consistently unchanged under various physiologic al and pathological conditions, was markedly reduced in ELBWI. Our results support the previous reports that neonatal erythrocytes have a unique metab olic pattern which is different from that of adult erythrocytes, and also s uggest that the 6PGD/G6PD ratio might be an index for the developmental imm aturity of fetal erythrocytes. This Is the first report describing the patt ern of erythrocyte enzyme activities in ELBWI. Am. J. Hematol 62:88-92, 199 9. (C) 1999 Wiley-Liss, Inc.