Ghrelin (GHSR)
Originally thought of as a stomach-derived endocrine peptide acting via its receptors in the central nervous system to stimulate food intake and growth hormone expression, ghrelin and its receptor (growth hormone secretagogue receptor (GHS-R), GPCR-A7 subfamily) are widely expressed in a number of organ systems, including cancer cells. Ghrelin is currently known to be the most potent endogenous inducer of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis and of food intake in mammals[1]. Endogenous ghrelin also appears to be an important modulator of physiological functions relevant to aging. Since endogenous ghrelin activity declines during aging, it has been hypothesized that GHS-R1a agonists may prove beneficial as interventive agents[2].
[1] Ghrelin and the Growth Hormone Secretagogue Receptor Constitute a Novel Autocrine Pathway in Astrocytoma Motility. V.D. Dixit et al. J. Biol. Chem. 2006, 281, 16681-16690.
[2] Ghrelin Receptor (GHS-R1A) Agonists Show Potential as Interventive Agents during Aging. R.G.Smith et al. Ann. N.Y.Ac.Sc. 2007, 119, 147-164.