IGFs and binding proteins in short children with intrauterine growth retardation.

Abstract

The aim of this study was to examine the relationship between the IGF-IGF binding protein (IGFBP) axis and insulin secretion in short intrauterine growth retardation (IUGR) children. Fifteen IUGR and 12 normal short prepubertal subjects had a 90-min frequently sampled iv glucose tolerance test performed to measure plasma glucose, insulin, IGF-I, IGF-II, IGFBP-3, and IGFBP-1. In addition, 29 nonobese prepubertal subjects of normal height had fasting plasma IGF-I and IGFBP-3 levels measured. In comparison to short normal subjects, IUGR subjects had higher plasma values for IGF-I (42 +/- 10 vs. 77 +/- 31 microg/liter; P < 0.0001), IGF-II (291 +/- 76 vs. 370 +/- 66 microg/liter; P < 0.008), IGFBP-3 (1.66 +/- 0.28 vs. 2.07 +/- 0.48 mg/liter; P < 0.0005), fasting insulin (2 +/- 1 vs. 4 +/- 2 mU/liter; P < 0.004), and acute insulin response (AIR; 215 +/- 36 vs. 504 +/- 90 mU/liter; P = 0.008). Nonobese subjects of normal height had higher plasma IGF-I (117 +/- 9 microg/liter; P < 0.0001) and IGFBP-3 (2.34 +/- 0.12 mg/liter) values than the IUGR group (P < 0.0005). During the frequently sampled iv glucose tolerance test, the magnitude of the AIR in short normal subjects was related to the fall in IGFBP-1 levels (P = 0.03); however, no relationship was seen between AIR and fall in IGFBP-1 in IUGR subjects (P = 0.24). In conclusion, short IUGR children have higher plasma IGF-I, IGF-II, and IGFBP-3, when compared with normal children matched for height, weight, and pubertal status. We speculate that hyperinsulinism secondary to insulin resistance may have led to these changes to the IGF-IGFBP axis in the IUGR group.