Clinical use of somatomedin-1: yes or no?

Insulin-like growth factor-I (IGF-I) is a polypeptide of 70 amino acids. The circulatory form of IGF-I is synthesised in the liver. The metabolic activity of IGF-I is regulated by 6 IGF binding proteins. the most important being IGF binding protein-3. IGF-I acts via its own receptor, which resembles that of insulin. It has been demonstrated that the effects of pituitary growth hormone (GH, somatropin) on protein metabolism, including growth and effects on nervous and renal tissue, are mediated by IGF-I, whereas these 2 hormones are antagonistic in their effects on insulin and some aspects of lipid metabolism. The biosynthesis of recombinant human IGF-I (somatomedin-1) in 1986 enabled the initiation of clinical trials. The most important involves replacement therapy in primary IGF-I deficiency, such as Laron syndrome (primary GH resistance or insensitivity), and in patients who have developed antibodies to human GH. In Laron syndrome, which is characterised by dwarfism, somatomedin-1 stimulates growth and increases muscle and bone mass, as well as normalising blood chemistry. In diabetes mellitus types 1 and 2 (insulin-dependent and non-insulin-dependent), somatomedin-1 increases the sensitivity to insulin and improves glucose utilisation, and may contribute to healing of injured nerve tissue and improve renal function in humans. Adverse effects of somatomedin-1 appear to be related to overdosage. In conclusion, somatomedin-1 is an important hormone which has clinical roles as replacement therapy and other pharmacological therapies.