The present study was performed with the objective of investigating the effects of recombinant human growth hormone (rhGH) supplementation on glucose metabolism in intra-uterine growth-retarded (IUGR) preterm newborn infants. At approximately 4 weeks of age, following 3 weeks of rhGH treatment, the metabolic rate was measured using indirect calorimetry. Glucose kinetics were measured using constant-rate infusion of [U- 1 3 C]glucose during continuous gavage feeding with special infant formula. 6 IUGR infants were treated with 1.0 IU kg - 1 day - 1 rhGH and 6 IUGR infants were studied as controls. The infants received a mean energy intake of 126 kcal kg - 1 d - 1 and a carbohydrate intake of 13.2 g kg - 1 d - 1 (50 kcal kg - 1 d - 1 ). Plasma glucose and insulin levels measured before and during treatment were similar in both groups. The rates of total glucose production were 10.1±1.2 and 10.0±1.3 mg kg - 1 min - 1 (n.s.) in the rhGH-treated and the control group, respectively. The rate of glucose oxidation calculated from the tracer data was 4.5±0.9 and 5.4±1.1 mg kg - 1 min - 1 (n.s.). The metabolic rate, calculated from the rate of oxygen consumption, was similar: 51.2±6.4 kcal kg - 1 d - 1 in the rhGH-treated group and 52.2±8.1 kcal kg - 1 d - 1 (n.s.) in the control group.Conclusion: rhGH treatment in IUGR preterm newborn infants does not have a significant impact on glucose and energy metabolism during adequate continuous oral feeding.