Description
MK-571 is a selective, orally active CysLT
1 receptor antagonist. It blocks the binding of LTD
4, but not LTC
4, to human and guinea pig lung membranes with K
i values of 0.22 nM and 2.1 nM, respectively, which is indicative of CysLT
1 receptor-
mediated activity in these preparations. MK-571 effectively blocks LTD
4 activation of recombinant human and murine CysLT
1 receptors but is ineffective at blocking LTC
4 or LTD
4 activation of the recombinant human or murine CysLT
2 receptors.
Biological Activity
Potent CysLT 1 (LTD 4 ) leukotriene receptor inverse agonist (EC 50 = 1.3 nM). Antagonizes LTD 4 -induced contractions of guinea pig trachea and ileum (pA 2 values are 9.4 and 10.5 respectively). Also inhibitor of multidrug resistance protein-1 (MRP1) mediated transport; in vitro augments the effects of cytotoxic agents on malignant cells.
References
1) Jones et al. (1989) Pharmacology of L-660,711 (MK-571): a novel potent and selective leukotriene D4 receptor antagonist.; Can. J. Physiol. Pharmacol. 67, 17
2) Dupre et al. (2004) Inverse agonist activity of selected ligands of the cysteinyl-leukotriene receptor 1; J. Pharmacol. Exp. Ther. 309 102
3) Vellenga et al. (1999) Interleukin-6 production by activated human monocytic cells is enhanced by MK-571, a specific inhibitor of the multi-drug resistance protein-1; Br .J. Pharmacol. 127 441