Relamorelin (RM-131) acetate is a pentapeptide ghrelin analog that acts as a selective agonist for the ghrelin/growth hormone secretagogue receptor (GHSR). It exhibits a high affinity for the GHS-1a receptor, with a Ki value of 0.42 nM. Notably, Relamorelin acetate can cross the blood-brain barrier and target the central nervous system. This compound effectively increases growth hormone levels and promotes faster gastric emptying. Due to these properties, Relamorelin acetate holds promise for its potential applications in research related to cachexia, gastroparesis, and gastric/intestinal dysmobility disorders [4] [5].

GHS-1a:0.42 nM (Ki)

Relamorelin (RM-131) acetate shows ～3 times greater affinity for GHS-1a (K i =0.42 nM) than native ghrelin (K i =1.12 nM). Relamorelin acetate is 6 times more potent (EC 50 =0.71 nM) in activating the GHS-1a receptor than native ghrelin (EC 50 =4.2 nM) as assessed in vitro by calcium mobilization[1].

Relamorelin (RM-131; 50-500 nmol/kg/day; s.c.; continuous infusion for 5 days) acetate decreases the loss of body mass and fat mass. Relamorelin (500 nmol/kg/day; continuous infusion for 5 days) acetate increases the food intake and weight gain in rats[1]. RM-131 (250-500?nmol/kg; a single s.c.) acetate stimulates acute food intake in wt but not growth hormone secretagogue receptor (GHR) ko mice[2]. Animal Model: F344/NTacfBR male rats implanted with tumor[1]Dosage: 50, 500 nmol/kg/day Administration: SC; continuous infusion at a rate of 0.5 μL/h for 5 d Result: Resulted in an increase in food intake (tumor/saline 41.4 g, tumor/BIM-28131 72.5 g) and weight gain (tumor/saline -10.3%, tumor/BIM-28131 +19.5%).