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.