EM574 is a motilin receptor agonist with an IC50 value of 6.17 nM for binding to rabbit gastric antral smooth muscle homogenates in a radioligand binding assay.1 It also binds to human smooth muscle homogenates in a radioligand binding assay (Kd = 7.8 nM).2 EM574 induces contraction of isolated rabbit, but not rat or guinea pig, intestine (EC50 = 5.5 nM).1 It increases antral motility and enhances gastric emptying in canine models of gastroparesis when administered intraduodenally at a dose of 0.03 mg/kg following a semi-solid meal.3
References
1. Sato, F., Sekiguchi, M., Marui, S., et al. EM574, an erythromycin derivative, is a motilin receptor agonist in the rabbit. Eur. J. Pharmacol. 322(1), 63-71 (1997).
2. Satoh, M., Sakai, T., Fujikura, K., et al. EM574, an erythromycin derivative, is a potent motilin receptor agonist in human gastric antrum. J. Pharmacol. Exp. Ther. 271(1), 574-579 (1994).
3. Sato, F., Marui, S., Inatomi, N., et al. EM574, an erythromycin derivative, improves delayed gastric emptying of semi-solid meals in conscious dogs. Eur. J. Pharmacol. 395(2), 165-172 (2000).