ARS | Publication request: Gluconeogenesis is not regulated by either glucose or insulin in extremely low birth weight infants receiving total parenteral nutrition

Submitted to: Journal of Pediatrics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 23, 2010
Publication Date: June 1, 2011
Citation: Chacko, S.K., Ordonez, J., Sauer, P.J., Sunehag, A.L. 2011. Gluconeogenesis is not regulated by either glucose or insulin in extremely low birth weight infants receiving total parenteral nutrition. Journal of Pediatrics. 158(6):891-896.

Interpretive Summary: Infants born prematurely are often dependent on nutrition by vein and are frequently unable to maintain blood sugar concentration within the normal range. In depth knowledge on the factors regulating blood sugar concentration is necessary to optimize nutritional strategies in these infants to maintain glucose homeostasis and promote growth and development. Gluconeogenesis is a process by which sugar is produced in the body and it contributes to maintain blood sugar concentration within a narrow range when the sugar supply is low. We reported that gluconeogenesis continues in premature infants even when they receive a sufficient sugar supply to cover their estimated needs. Further, in contrast to adults, in preterm infants we found that gluconeogenesis is not controlled by either concentrations of sugar or hormones known to regulate sugar metabolism. Our study provided new information that is important for defining nutritional guidelines in prematurely born infants during their early days of life.

Technical Abstract: The objective was to determine potential factors regulating gluconeogenesis (GNG) in extremely low birth weight infants receiving total parenteral nutrition. Seven infants (birth weight, 0.824 +/- 0.068 kg; gestational age, 25.4 +/- 0.5 weeks; postnatal age, 3.3 +/- 0.2 days) were studied for 11 hours, with parenteral lipid and amino acid therapy continued at prestudy rates. Glucose was supplied at prestudy rates for the first 5 hours (period 1) and was then reduced to 6 mg/kg per min for 1 hour and further to ~3 mg/kg per min for 5 hours (period 2). A total of 2.5 mg/kg per min of the glucose was replaced by [U-13C]glucose throughout the study for measurements of glucose production and GNG. Concentrations of glucose, insulin, glucagons, and cortisol were determined. GNG and glucose production remained unchanged (2.12 +/- 0.23 vs. 1.84 +/- 0.25 mg/kg per min [P = NS] and 2.44 +/- 0.27 vs. 2.51 +/- 0.31 mg/kg per min [P = NS], respectively), despite a 60% reduction of the glucose infusion rate and subsequent 30% (124.7 +/- 10.8 to 82.6 +/- 8.9 mg/dL; P = .009) and 70% (26.9 +/- 4.7 to 6.6 +/- 0.4 uU/mL; P = .002) decreases in glucose and insulin concentrations, respectively. Cortisol and glucagon concentrations remained unchanged. In extremely low birth weight infants receiving total parenteral nutrition, GNG is a continuous process that is not affected by infusion rates of glucose or concentrations of glucose or insulin.