Changes in protein turnover, IGF-I and IGF binding proteins in children with cancer

Changes in insulin‐like growth factor‐I (IGF‐I) and insulin‐like growth factor binding proteins (IGFBPs) were correlated with protein synthesis and breakdown using [1‐ 13C]leucine before chemotherapy and during subsequent febrile neutropenia (FN) in eight children with cancer, aged 6.3–17.5 y. IGF‐I levels were similar to age‐matched controls before chemotherapy (mean ±SEM: 250 ±28 and 228 ±22 μg l‐1, respectively). During FN, IGF‐I fell to 156 ±22 /ng l ‐1(p= 0:02), and rose to 276 ±27 μ g l ‐1 with recovery at 6 months (p = 0:004). Similarly, IGFBP‐3 decreased from 4.0 ±0.2mgl‐1 before chemotherapy to 3.0 ±0.3 mgl‐1 during FN (p= 0:01), and returned to 4.1 ±0.2mgl ‐1 at 6 months (p= 0:01). IGF‐I correlated with IGFBP‐3 (r=+0:7, p