Adenine nucleotide concentrations in liver of fetal rats. Neonatal changes in the premature newborn.

Changes in ATP, ADP and AMP concentrations in the liver in term and preterm newborns during the perinatal period have been studied. Fetal liver ATP concentrations decreased during the penultimate day of gestation and remained low during the last day of pregnancy. ATP concentrations sharply increased in the liver of term newborns immediately after delivery, remaining unchanged after 1 h of extrauterine life. High ATP concentrations were observed in the liver of preterm newborns at delivery without changes within the early postnatal period. No significant changes in liver ADP and AMP concentrations were observed in either group throughout the observation period. Energy charge was higher in preterm liver at delivery but similar values were reached in term liver after 30 min of extrauterine life. These results suggest that the energy stage of the preterm liver is high at delivery without changes during the early postnatal period.