Transient catabolic state with reduced IGF-I after antenatal glucocorticoids.

Glucocorticoid (GC) administration before preterm birth reduces neonatal morbidity but may restrain growth. Here we explored the effect of antenatal GC on nutrient substrates (glucose, FFA, amino acids (AA)), and on IGF-I and IGF-binding protein-1 (IGFBP-1). We analyzed umbilical vein (UV) plasma obtained at birth from 91 preterm newborns that received one course of GC (last exposure 1-1358 h before birth) and 49 newborns that did not. We found that recent GC exposure (48 h) raised glucose, FFA, and AA concentrations, and the homeostasis model assessment of insulin resistance (HOMA-IR) index, but lowered IGF-I concentrations. The AA surge was greater in newborns with a birth weight z score 0 than in those with a z score 0. Although all AA were transiently increased, the increment was most robust for glutamine and alanine. Shorter duration since GC administration and lower IGF-I concen- trations independently predicted AA levels. In conclusion, an ante- natal course of GC elicited a transient catabolic state encompassing all nutrient substrates, and a temporary drop in IGF-I concentrations. These changes may explain the growth-inhibitory effects of repeated antenatal GC administration. Future research should clarify the role of IGF-I in the protein-catabolic response to GC. (Pediatr Res 62: 295-300, 2007)