Recombinant human growth hormone (somatotropin) 191 residues, MW 22.1 kD, synthesized in E. coli
Used in the treatment of dwarfism and growth failure, growth hormone (hGH) stimulates skeletal growth in pediatric patients with growth failure due to a lack of adequate secretion of endogenous GH. Skeletal growth is accomplished at the epiphyseal plates at the ends of a growing bone. Growth and metabolism of epiphyseal plate cells are directly stimulated by GH and one of its mediators, IGF-I (insulin-like growth factor).
For treatment of dwarfism, acromegaly and prevention of HIV-induced weight loss
hGH binds to the human growth hormone receptor (GHR). Upon binding, hGH causes dimerization of GHR, activation of the GHR-associated JAK2 tyrosine kinase, and tyrosyl phosphorylation of both JAK2 and GHR. These events recruit and/or activate a variety of signaling molecules, including MAP kinases, insulin receptor substrates, phosphatidylinositol 3' phosphate kinase, diacylglycerol, protein kinase C, intracellular calcium, and Stat transcription factors. These signaling molecules contribute to the GH-induced changes in enzymatic activity, transport function, and gene expression that ultimately culminate in changes in growth and metabolism.