Ghrelins

Small synthetic molecules called growth-hormone secretagogues (GHSs) stimulate the release of growth hormone (GH) from the pituitary through a G protein-coupled receptor (GHS-R). Recently, ghrelin ("ghre" is the Proto-Indo-European root of the word "grow") has been identified as an endogenous ligand for GHS-R. These peptides consist of 28 amino acids with an octanoyl-residue at Ser3, which is essential for expressing activity. Ghrelin stimulates GH release from rat primary culture pituitary cells in a dose-dependent manner and induces an increase in intracellular Ca2+ in GHS-R-expressing cells with an EC50 value of 2.5 nM. Human ghrelin is homologous to rat ghrelin apart from two amino acids. The occurrence of ghrelin in both rat and human indicates that GH release from the pituitary may be regulated not only by hypothalamic GHRH, but also by ghrelin. In future, ghrelin might be used in the treatment of aging patients as well as in patients with idiopathic GH deficiency, obesity, osteoporosis or cardiovascular diseases.

Family Literatur:
M.Kojima et al., Nature, 402, 656 (1999)
C.Dieguez and F.F.Casanueva, Eur. J. Endocrinol., 142, 413 (2000)