Classification of ghrelin receptor

Receptor Ghrelin, GRLN
Receptor code 2.1:GHS:1:GHS1:HUMAN:00
Previous names GHS-R, GHS-R1a (approved human gene symbol)
Structural information 7TM
Human: 366aa (SwissProt Q92847), chr. 3q26.31 (LocusLink 2693)
Rat: 364aa (SwissProt O08725), chr. 2Q24 (LocusLink 84022)
Mouse: 364aa (SwissProt Q99P50), chr. 3A3 (LocusLink 208188)
Functional assays In vitro pharmacology using human isolated vessels (Wiley and Davenport, 2002)
In vitro pharmacology using isolated guinea pig papillary muscle (Bedendi et al., 2003)
Endogenous agonists Ghrelin (IC50 = 8.1 nM/EC50 = 1.5 nM) = des-Gln14-ghrelin (IC50 = 7.4 nM/EC50 = 1.5 nM) (Matsumoto et al., 2001; Bedendi et al., 2003)
Selective agonists GHRP-2 (IC50 = 0.4 nM) > MK-0677 (IC50 = 0.8 nM) > GHRP-6 (IC50 = 1.5 nM) (cloned rat receptor; McKee et al., 1997)
Antagonists [d-Lys3]-GHRP-6, EP-80317
Antagonist potencies
Radioligand assays Human hypothalamus, human cardiovascular tissue
Radioligands [125I-His9]-ghrelin, (Kd = 0.22–0.57 nM) (Katugampola et al., 2001)
[125I-Tyr4]-ghrelin (Kd = 0.44 nM) (Muccioli et al., 2001)
[125I-Tyr4]-ghrelin (Kd = 0.51 nM) (Bedendi et al., 2003)
Mechanism Coupled to G-α-11 proteins
Receptor distribution Humans, specific [125I-His9]-ghrelin binding was localized to the human vasculature including aorta, coronary arteries, pulmonary arteries, arcuate arteries (in the kidney), and saphenous veins; rats: binding sites were also localized to the vasculature in peripheral tissues as well as the granular layer of the cerebellum in the CNS (Katugampola et al., 2001)
Tissue function Stimulates release of growth hormone from the anterior pituitary, gastric acid secretion, and motility; may alter appetite and energy balance; vasodilation
  • aa, amino acid; chr., chromosome.