Motilin (26-47), human, porcine

Motilin (26-47), human, porcine is an endogenous motilin receptor ligand with K_i and EC₅₀ of 2.3 nM and 0.3 nM in a Chinese hamster ovary cell line. IC50 & Target: EC50: 0.3 nM (motilin receptor, Chinese hamster ovary cell)^[1]
Ki: 2.3 nM (motilin receptor, Chinese hamster ovary cell)^[1] In Vitro: [Bpa¹,Ile¹³]motilin is a full agonist at the motilin receptor that increases intracellular calcium in a concentration-dependent manner (EC₅₀ = 1.5 ± 0.4 nM)^[1]. Motilin binds with high affinity (IC₅₀ 0.7± 0.2 nM) to receptors on smooth muscle cells. Motilin selectively activates G(q) and G(13), stimulates G alpha(q)-dependent phosphoinositide (PI) hydrolysis and 1,4,5-trisphosphate (IP(3))-dependent Ca²⁺ release, and increases cytosolic free Ca²⁺. Motilin induces a biphasic, concentration-dependent contraction (EC₅₀ = 1.0 +/- 0.2 nM), consisting of an initial peak followed by a sustained contraction^[2].