Effects of antenatal steroids on protein metabolism in preterm infants on the first day of life.

Objective: To analyze, in an existing cohort of infants, whether antenatal administered corticosteroids influence protein metabolism in preterm infants on the first day of life. Study design Three groups of infants were studied. The mothers of 25 infants had received 2 or more doses of corticosteroids, the mothers of 5 had received 1 dose, and there was no antenatal steroid exposure for 8 infants. Within a few hours after birth, a double-tracer leucine infusion was started by intravenous and intragastric routes and continued for 5 hours while the infants received only intravenous glucose.

Results: The plasma alpha-keto-isocaproic acid (KIC) enrichment (mol percent excess, MPE) from the intravenous tracer was not different between infants who reveived no antenatal steroids (8.58+/-1.64), 1 dose (7.60+/-0.78), and 2 or more doses (7.61+/-1.29). From the intragastric tracer, the plasma KIC enrichment from the intragastric tracer was different among the 3 groups, 7.62+/-2.35 for 0 doses, 5.78+/-0.85 for 1 dose, and 5.53+/-1.58 for 2 or more doses of antenatal steroids. Plasma KIC enrichment from the intravenous tracer was significantly higher than from the intragastric tracer in infants who received antenatal steroids, whereas there was no difference in infants who had not received antenatal steroids. Plasma leucine enrichment showed the same results.

Conclusions: Antenatal corticosteroid administration to the fetus has no effect on whole-body leucine metabolism on the first day of life. However, it is associated with an increase in splanchnic leucine uptake at birth.