Urinary insulin-like growth factor-II excretion in healthy infants and children with normal and abnormal growth.

The output of urinary IGF-II was measured by RIA in 12-h overnight urine samples obtained from 22 preterm and 15 full-term infants, 40 normal children, 18 children with growth hormone (GH) deficiency, and 25 patients with idiopathic short stature. GH deficiency was defined as a peak to GH provocative tests < or = 9.9 micrograms/L during two provocative tests. The authenticity of urinary IGF-II was confirmed by size exclusion chromatography. Statistical analysis was performed by one-way analysis of variance using the Student Neuman-Keuls test to detect intergroup differences at the level of p < 0.05. The preterm and full-term infants excreted significantly higher amounts of urinary IGF-II (18.4 +/- 1.7 and 5.7 +/- 1.0 pmol/kg, respectively) compared with normal children (2.4 +/- 0.25 pmol/kg; p < 0.001). The output of urinary IGF-II in preterm infants was greater than that observed in full-term infants (F = 84.7, p < 0.001). The control children excreted significantly more IGF-II (2.4 +/- 0.2 pmol/kg) than children with GH deficiency (0.9 +/- 0.1 pmol/kg) or idiopathic short stature (1.0 +/- 0.1 pmol/kg; F = 13.5; p < 0.001). Analysis of urinary IGF-II excretion based on creatinine output yielded similar results. Data on urinary IGF-I and GH previously published were correlated and compared with the excretion pattern of urinary IGF-II.(ABSTRACT TRUNCATED AT 250 WORDS)