Sodium potassium adenosine triphosphatase activity in preterm and term infants and its possible role in sodium homeostasis during maturation

Abstract

(Arch Dis Child Fetal Neonatal Ed 1999;81:F184-F187)

Developmental changes in erythrocyte Na+,K+-ATPase subunit abundance and enzyme activity in neonates

“…On the other hand, contrary to our present and the above mentioned previous findings,6 10-12 a recent study by Bistritzer et al 13 found that cord blood erythrocyte ATPase activity is lower in preterm neonates of between 30 and 34 weeks of gestation than neonates of ⩾ 35 weeks gestation. However, as Na + ,K + -ATPase activity has been reported to increase after birth in preterm neonates,8 it is possible that the use of cord blood by Bistritzer et al affected their findings.…”

“…However, as Na + ,K + -ATPase activity has been reported to increase after birth in preterm neonates,8 it is possible that the use of cord blood by Bistritzer et al affected their findings. In support of this hypothesis is the fact that they themselves reported a postnatal increase in erythrocyte Na + ,K + -ATPase activity in their preterm neonates 13. Finally, our findings are strengthened by the enrollment of a larger patient population including more immature preterm neonates and by the downregulation of the α 1 subunit isoform in term neonates, suggesting the presence of an indirect relation between erythrocyte Na + ,K + -ATPase activity and gestational age.…”

“…10-13 Most studies on erythrocyte Na + ,K + -ATPase activity during development have shown higher enzyme activity6 10 11 and ouabain binding capacity12 in the immature animal and neonate than in the mature newborn. However, a recent study found that cord blood erythrocyte Na + ,K + -ATPase activity is lower in preterm than term neonates 13. In addition to these conflicting results, the developmentally regulated changes in the relation between isoform composition and enzyme function have also not been clarified.…”

Expression and Activity of the Ca²⁺-ATPase Enzyme in Human Neonatal Erythrocytes

“…Recently it has been reported that the expression and activity of Na + /K + -ATPase changes during perinatal and postnatal development [9][10][11]. The activity of the Na + /H + countertransport system also changes postnatally [12].…”

Using Enteral Sterile Water Feeds for Hypernatremia in Extremely Low Birth-Weight Infants

“…19 It may also play a role in sodium homeostasis during postnatal maturation in the premature infant. 20 Bradykinin is a major operative vasodilator that primarily affects pretubular renal arteries, contributing to an increase in GFR.…”