SM-130,686 is a potent, orally-active agonist of the ghrelin growth hormone secretagogue receptor (GHSR) and growth hormone secretagogue. It has around half the potency of the endogenous agonist ghrelin as a stimulator of growth hormone release.
PF-04628935 is a potent antagonist inverse agonist of the ghrelin receptor, growth hormone secretagogue receptor 1a (GHS-R1a) with an IC50 of 4.6 nM. PF-04628935 is orally bioavailable and brain penetrant.