Use of insulin-like growth factor-binding protein-2 (IGFBP-2), IGFBP-3, and IGF-I for assessing growth hormone status in short children.

Insulin-like growth factor-binding protein-2 and -3 (IGFBP-2 and -3) are members of a family of proteins that are present in extracellular fluids and bind IGF-I and -II. IGFBP-2 is regulated differently from IGF-I and IGFBP-3, because its serum concentrations are elevated in some adults with GH deficiency (GHD), whereas IGF-I and IGFBP-3 concentrations are usually decreased. The purposes of this study were to define the normal range of IGFBP-2 concentrations in children, to determine its efficacy in the diagnosis of GHD, and to compare the diagnostic value of measurements of the serum GH response to provocative testing with results of measurements of IGFBP-2, IGFBP-3, and IGF-I. Mean serum IGFBP-2 concentrations ranged from 263 +/- 101 ng/mL (mean +/- SD) during infancy to 136 +/- 38 ng/mL in normal 15- to 18-yr-olds (P 10 ng/mL), 7 had low IGF-I values. Of the 7, all had an increased IGFBP-2/IGF-I ratio and a low IGFBP-3 level. Of the remaining 16 children with normal IGF-I, 13 had a normal IGFBP-2/IGF-I ratio and normal IGFBP-3 values. Three had low IGFBP-3 and an increased IGFBP-2/IGF-I ratio. In 76% of the 80 short-statured patients studied, there was concordance among serum GH responses to provocative tests, IGF-I, IGFBP-2/IGF-I ratio, and IGFBP-3.(ABSTRACT TRUNCATED AT 400 WORDS)