RLX-33 is a potent, selective and blood-brain barrier (BBB) penetrant relaxin family peptide 3 (RXFP3) antagonist, also blocks relaxin-3-induced ERK1/2 phosphorylation, with IC 50 values of 2.36 μM for RXFP3, 7.82 and 13.86 μM for ERK1 and ERK2 phosphorylation, respectively. RLX-33 can block the stimulation of food intake induced by the RXFP3-selective agonist R3/I5 in rats. RLX-33 can be used for the research of metabolic syndrome In Vivo RLX-33 (10 mg/kg; IP, single dosage) attenuates the RXFP3-selective agonist R3/I5-induced increase in feeding in male Wistar rats . RLX-33 (10 mg/kg; IP, single dosage) exhibits a good brain penetration and highly protein-bound in rats plasma . Pharmacokinetic Parameters of RLX-33 in male Wistar rats (IP, 10 mg/kg) . plasma brain C max (ng/mL) 1401 1552 t max (h) 0.5 2.0 t 1/2 (h) 1.9 4.9 AUC inf (ng/mL·h) 5352 12519 CL_F (mL/min/kg) 43.8 MCE has not independently confirmed the accuracy of these methods. They are for reference only. Animal Model: Male Wistar rats (intracerebroventricular administration of R3/I5 stimulated food intake Dosage: 10 mg/kg Administration: IP, single dosage Result: Attenuated the R3/I5-induced increase in food intake. Animal Model: Male Wistar rats Dosage: 10 mg/kg Administration: IP, single dosage (Pharmacokinetic Analysis) Result: Exhibited a good brain penetration and highly protein-bound, with protein binding of 99.8% in rat plasma. Form:Solid IC50& Target:IC 50 : 2.36 μM (RXFP3), 7.82 μM (ERK1 phosphorylation), 13.86 μM (ERK2 phosphorylation)