Glucose oxidation rates in newborn infants measured with indirect calorimetry and [U-13C]glucose.

Indirect calorimetry and primed constant infusion of [U-13C]glucose were combined in 16 appropriate-for-gestational age newborn, parenterally fed infants, in order to measure glucose utilization and glucose oxidation respectively. Glucose intake ranged between 10.0 and 24.1 g day-1 kg-1 and energy intake between 156.9 and 439.3 kJ day-1 kg-1. Glucose utilization (P less than 0.001), glucose oxidation (P less than 0.001) and metabolic rate (P less than 0.005) increased significantly with rising glucose intake. The significant difference between glucose utilization and oxidation (P less than 0.001) can be accounted for by an increasing storage as fat. As lipogenesis from glucose consumes 15-24% of the original glucose energy, the increasing metabolic rate accompanying rising glucose intake is probably due to increasing lipogenesis.