GHSR
GHSR (Growth hormone secretagogue receptor) is a G protein-coupled receptor that binds ghrelin and plays a role in energy homeostasis and regulation of body weight. In the brain, they are located in the hypothalamic ventromedial nucleus and arcuate nucleus, as well as in ventral tegmental area dopamine neurons projecting to the nucleus accumbens. Ghrelin is an appetite-regulating factor secreted from peripheral organs that is involved in regulation of energy homoeostasis via binding to the receptor resulting in the secretion of growth hormone by the pituitary gland. The pathway activated by binding of ghrelin to the growth hormone secretagogue receptor, GHSR1a, regulates the activation of the downstream mitogen-activated protein kinase, Akt, nitric oxide synthase, and AMPK cascades in different cellular systems. One of the important features of GHSR1a displays constitutive activity possessing basal activity in the absence of an agonist, resulting in a high degree of receptor internalization as well as of signaling activity. Inverse agonists for the ghrelin receptor could be particularly interesting for the treatment of obesity. This activity seems to provide a tonic signal required for the development of normal height, probably through an effect on the GH axis.
