Cyclic Nucleotides and Mitochondrial Functions at Birth

ATP production in the fetal rat liver is mainly glycolytic, glucose being supplied by the mother’s blood (1). The capacity of liver mitochondria for ATP synthesis coupled to succinate oxidation is low at birth. It increases by 70% between delivery and two hours after birth as shown by the respiratory control ratios obtained, reflecting a rapid mitochondrial maturation (2). This improvement in the capacity of ATP synthesis through the oxidative phosphorylation machinery is one of the early events occurring in rat liver mitochondria at birth. The rapid mechanism by which this improvement occurs is not yet fully understood.