GH, IGF-I, and growth

Recent studies have confirmed the importance of the growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis as the major determinant of whole body growth in animals and humans and have highlighted the significance of IGF-I to human growth. Pharmacological studies in rodents and therapeutic studies in humans demonstrate that recombinant human (rh)IGF-I can induce a significant statural growth response. Mouse gene knockout studies have shown that IGF-I, rather than GH, is the major hormone controlling whole body growth. The relative importance of endocrine versus local IGF-I remains unresolved. In children who are GH- and IGF-I-deficient, treatment with GH stimulates a robust growth response. In children who are IGF-I-deficient but GH-sufficient, rhIGF-I might also be a useful treatment. Furthermore, pharmacological and genetic studies in animals show effects requiring the combined presence of GH and IGF-I, suggesting that rhGH and rhIGF-I together might be the optimal treatment for some children with short stature.