Assays for GH, IGF-I, and IGF Binding Protein-3

The growth hormone/insulin-like growth factor (GH/IGF) axis is widely investigated in disorders of growth, development, and anterior pituitary function. Methods are described for three hormones in this axis (growth hormone, IGF-I, and IGF binding protein-3). Enzyme-linked immunosorbent assays (ELISAs) are described as they combine the specificity of antibody–antigen interactions with the sensitivity of simple enzyme assays. Many commercial immunoassays are available for the measurement of GH and IGF-I, and the main problems encountered in the measurement of these clinically important hormones are discussed.