Abstract
Background: After birth the newborn infant must produce its own glucose until breastfeeding is established. Infants born small for gestational age (SGA) are at risk for neonatal hypoglycemia and development of metabolic syndrome in adulthood. The aim of this study was to investigate glucose production and lipolysis in newborn infants born SGA.
Methods: Thirteen infants were studied at a mean age of 23±6-h, following fast for 4±0.3-h. Mean gestational age was 35±2.5 weeks and mean birth weight 1.8±0.42 kg (<− 2 SD). Six of the infants obtained glucose infusion to avoid hypoglycemia. Rates of glucose production (GPR) and lipolysis were quantitated by use of [6,6–2H2]-glucose and [2–13C]-glycerol.
Results: Plasma levels of glucose and glycerol were 4.1±1.1 mmol. L−1 and 217±64 ìmol.L−1, respectively. For all infants the rate of glucose appearance (glucose Ra) averaged 30.7±8.3 and that of GPR 22.1±6 ìmol. kg−1. min−1. GPR for infants obtaining additional glucose was 19.0±6.8 ìmol. kg−1. min−1 whereas those without glucose infusion produced 24.2±4.4 ìmol. kg−1. min−1. The rate of glycerol production, reflecting lipolysis, was 6.0±1.3 ìmol. kg−1. min−1 (corresponding values in the groups with and without glucose infusion were 5.1±1.7 and 6.6±0.9 ìmol. kg−1. min−1). Lipolysis correlated strongly to birth weight (r= 0.86, p< 0.001). Of the glycerol produced, 50±20 % was converted to glucose, representing 7.5±3 % of GPR. Concentrations of insulin (n= 11) and glucagon (n= 11) measured during steady state were 7.2±4 mU. L−1 and 78±31 pmol. L−1.
Conclusion: Our results show that SGA-infants have capacity for glucose production and lipolysis as well as for gluconeogenesis during their first day of life. In comparison with reported results from AGA-infants the present data is in the lower normal range. The correlation between glycerol production and birth weight indicates that lipolysis is dependent on the amount of depot fat. Although SGA-infants have a functioning hormonal regulation and enzymatic capacity for production of energy substrates, the small energy stores in this group of newborns may explain the increased risk of hypoglycemia. There are earlier reports of neonatal hyperinsulinemia in infants born SGA. However, all infants examined had normal insulin levels during the study period, contradicting early onset of insulin resistance.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Diderholm, B., Ewald, U., Ahlsson, F. et al. 73 Metabolic Adaptation in Infants Born Small for Gestational Age. Pediatr Res 56, 476 (2004). https://doi.org/10.1203/00006450-200409000-00096
Issue Date:
DOI: https://doi.org/10.1203/00006450-200409000-00096